From c34c08a86afe6996b0551880d56001613533a387 Mon Sep 17 00:00:00 2001
From: Sam Harwell <sam.harwell@microsoft.com>
Date: Fri, 30 Jun 2017 18:50:23 -0500
Subject: [PATCH 01/77] Use IVsUIShell instead of DTE to open the Options
 dialog

Fixes cases where an IOleCommandTarget in the chain fails to propagate
the call in a manner that allows arguments, which would crash Visual
Studio with a COMException.
---
 .../PreviewPane/PreviewPane.xaml.cs               | 15 ++++++++++-----
 .../PreviewPane/PreviewPaneService.cs             | 10 ++++++----
 2 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/src/VisualStudio/Core/Def/Implementation/PreviewPane/PreviewPane.xaml.cs b/src/VisualStudio/Core/Def/Implementation/PreviewPane/PreviewPane.xaml.cs
index dc03925fe1eb4..ff2ccf4c83359 100644
--- a/src/VisualStudio/Core/Def/Implementation/PreviewPane/PreviewPane.xaml.cs
+++ b/src/VisualStudio/Core/Def/Implementation/PreviewPane/PreviewPane.xaml.cs
@@ -7,11 +7,12 @@
 using System.Windows.Controls;
 using System.Windows.Documents;
 using System.Windows.Navigation;
-using EnvDTE;
 using Microsoft.CodeAnalysis.Diagnostics.Log;
 using Microsoft.VisualStudio.LanguageServices.Implementation.Utilities;
 using Roslyn.Utilities;
 using Microsoft.CodeAnalysis.Editor.Implementation.Preview;
+using IVsUIShell = Microsoft.VisualStudio.Shell.Interop.IVsUIShell;
+using OLECMDEXECOPT = Microsoft.VisualStudio.OLE.Interop.OLECMDEXECOPT;
 
 namespace Microsoft.VisualStudio.LanguageServices.Implementation.PreviewPane
 {
@@ -24,7 +25,7 @@ internal partial class PreviewPane : UserControl, IDisposable
 
         private readonly string _id;
         private readonly bool _logIdVerbatimInTelemetry;
-        private readonly DTE _dte;
+        private readonly IVsUIShell _uiShell;
 
         private bool _isExpanded;
         private double _heightForThreeLineTitle;
@@ -39,14 +40,14 @@ internal partial class PreviewPane : UserControl, IDisposable
             string helpLinkToolTipText,
             IReadOnlyList<object> previewContent,
             bool logIdVerbatimInTelemetry,
-            DTE dte,
+            IVsUIShell uiShell,
             Guid optionPageGuid = default(Guid))
         {
             InitializeComponent();
 
             _id = id;
             _logIdVerbatimInTelemetry = logIdVerbatimInTelemetry;
-            _dte = dte;
+            _uiShell = uiShell;
 
             // Initialize header portion.
             if ((severityIcon != null) && !string.IsNullOrWhiteSpace(id) && !string.IsNullOrWhiteSpace(title))
@@ -358,7 +359,11 @@ private void OptionsButton_Click(object sender, RoutedEventArgs e)
         {
             if (_optionPageGuid != default(Guid))
             {
-                _dte.ExecuteCommand("Tools.Options", _optionPageGuid.ToString());
+                ErrorHandler.ThrowOnFailure(_uiShell.PostExecCommand(
+                    VSConstants.GUID_VSStandardCommandSet97,
+                    (uint)VSConstants.VSStd97CmdID.ToolsOptions,
+                    (uint)OLECMDEXECOPT.OLECMDEXECOPT_DODEFAULT,
+                    _optionPageGuid.ToString()));
             }
         }
     }
diff --git a/src/VisualStudio/Core/Def/Implementation/PreviewPane/PreviewPaneService.cs b/src/VisualStudio/Core/Def/Implementation/PreviewPane/PreviewPaneService.cs
index ea765534c4c91..5add7a32d0f27 100644
--- a/src/VisualStudio/Core/Def/Implementation/PreviewPane/PreviewPaneService.cs
+++ b/src/VisualStudio/Core/Def/Implementation/PreviewPane/PreviewPaneService.cs
@@ -18,18 +18,20 @@
 using Microsoft.VisualStudio.Imaging.Interop;
 using Microsoft.VisualStudio.LanguageServices.Implementation.Utilities;
 using Microsoft.VisualStudio.Shell;
+using IVsUIShell = Microsoft.VisualStudio.Shell.Interop.IVsUIShell;
+using SVsUIShell = Microsoft.VisualStudio.Shell.Interop.SVsUIShell;
 
 namespace Microsoft.VisualStudio.LanguageServices.Implementation.PreviewPane
 {
     [ExportWorkspaceServiceFactory(typeof(IPreviewPaneService), ServiceLayer.Host), Shared]
     internal class PreviewPaneService : ForegroundThreadAffinitizedObject, IPreviewPaneService, IWorkspaceServiceFactory
     {
-        private readonly EnvDTE.DTE _dte;
+        private readonly IVsUIShell _uiShell;
 
         [ImportingConstructor]
         public PreviewPaneService(SVsServiceProvider serviceProvider)
         {
-            _dte = serviceProvider.GetService(typeof(EnvDTE.DTE)) as EnvDTE.DTE;
+            _uiShell = serviceProvider.GetService(typeof(SVsUIShell)) as IVsUIShell;
         }
 
         IWorkspaceService IWorkspaceServiceFactory.CreateService(HostWorkspaceServices workspaceServices)
@@ -107,7 +109,7 @@ private static Uri GetHelpLink(DiagnosticData diagnostic, string language, strin
 
                 return new PreviewPane(
                     severityIcon: null, id: null, title: null, description: null, helpLink: null, helpLinkToolTipText: null,
-                    previewContent: previewContent, logIdVerbatimInTelemetry: false, dte: _dte);
+                    previewContent: previewContent, logIdVerbatimInTelemetry: false, uiShell: _uiShell);
             }
 
             var helpLinkToolTipText = string.Empty;
@@ -128,7 +130,7 @@ private static Uri GetHelpLink(DiagnosticData diagnostic, string language, strin
                 helpLinkToolTipText: helpLinkToolTipText,
                 previewContent: previewContent,
                 logIdVerbatimInTelemetry: diagnostic.CustomTags.Contains(WellKnownDiagnosticTags.Telemetry),
-                dte: _dte,
+                uiShell: _uiShell,
                 optionPageGuid: optionPageGuid);
         }
 

From d198918eec4deba9a5d264eae1c547b88eb3bb48 Mon Sep 17 00:00:00 2001
From: Jonathon Marolf <jmarolf@microsoft.com>
Date: Tue, 25 Jul 2017 20:31:03 -0700
Subject: [PATCH 02/77] update roslyn version

---
 build/Targets/Versions.props | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/build/Targets/Versions.props b/build/Targets/Versions.props
index 21d63c7d200b0..4d946c2949b5e 100644
--- a/build/Targets/Versions.props
+++ b/build/Targets/Versions.props
@@ -9,9 +9,9 @@
 
   <PropertyGroup>
     <!-- This is the assembly version of Roslyn from the .NET assembly perspective. It should only be revved during significant point releases. -->
-    <RoslynAssemblyVersionBase Condition="'$(RoslynAssemblyVersion)' == ''">2.3.0</RoslynAssemblyVersionBase>
+    <RoslynAssemblyVersionBase Condition="'$(RoslynAssemblyVersion)' == ''">2.4.0</RoslynAssemblyVersionBase>
     <!-- This is the file version of Roslyn, as placed in the PE header. It should be revved during point releases, and is also what provides the basis for our NuGet package versioning. -->
-    <RoslynFileVersionBase Condition="'$(RoslynFileVersionBase)' == ''">2.3.2</RoslynFileVersionBase>
+    <RoslynFileVersionBase Condition="'$(RoslynFileVersionBase)' == ''">2.4.0</RoslynFileVersionBase>
     <!-- The release moniker for our packages.  Developers should use "dev" and official builds pick the branch
          moniker listed below -->
     <RoslynNuGetMoniker Condition="'$(RoslynNuGetMoniker)' == ''">dev</RoslynNuGetMoniker>

From d270313c46d242eb585ae9304763274d96df6537 Mon Sep 17 00:00:00 2001
From: Jonathon Marolf <jmarolf@microsoft.com>
Date: Tue, 25 Jul 2017 20:36:16 -0700
Subject: [PATCH 03/77] adding branch to publish list

---
 src/Tools/MicroBuild/publish-assets.ps1 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Tools/MicroBuild/publish-assets.ps1 b/src/Tools/MicroBuild/publish-assets.ps1
index 3172e22919234..2db2388c7aa96 100644
--- a/src/Tools/MicroBuild/publish-assets.ps1
+++ b/src/Tools/MicroBuild/publish-assets.ps1
@@ -37,7 +37,7 @@ try
     
     switch ($branchName)
     {
-        "dev15.3.x" { }
+        "dev15.4.x" { }
         "master" { }
         default
         {

From 1e6e3fb3a27374c7b4f877d7e97faa385b63aee4 Mon Sep 17 00:00:00 2001
From: Andrew Casey <andrew.casey@microsoft.com>
Date: Tue, 25 Jul 2017 16:57:45 -0700
Subject: [PATCH 04/77] Handle navigation to a doc ID without a corresponding
 doc

---
 .../ProjectSystem/VisualStudioWorkspaceImpl.cs              | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/VisualStudio/Core/Def/Implementation/ProjectSystem/VisualStudioWorkspaceImpl.cs b/src/VisualStudio/Core/Def/Implementation/ProjectSystem/VisualStudioWorkspaceImpl.cs
index d27587ad0e88b..36d7a9d200bba 100644
--- a/src/VisualStudio/Core/Def/Implementation/ProjectSystem/VisualStudioWorkspaceImpl.cs
+++ b/src/VisualStudio/Core/Def/Implementation/ProjectSystem/VisualStudioWorkspaceImpl.cs
@@ -997,6 +997,12 @@ internal override DocumentId GetDocumentIdInCurrentContext(DocumentId documentId
             }
 
             var hostDocument = GetHostDocument(documentId);
+            if (hostDocument == null)
+            {
+                // This can happen if the document was temporary and has since been closed/deleted.
+                return base.GetDocumentIdInCurrentContext(documentId);
+            }
+
             var itemId = hostDocument.GetItemId();
             if (itemId == (uint)VSConstants.VSITEMID.Nil)
             {

From e47543b238cd0adf8ed146aedf25ff48f76482ec Mon Sep 17 00:00:00 2001
From: Ravi Chande <rchande@microsoft.com>
Date: Mon, 24 Apr 2017 15:01:37 -0700
Subject: [PATCH 05/77] Implement INavigableSymbols

Breaks the internal GTD infrastructure into seperate symbols for
determining the navigable symbol at the caret position and performing
the navigation.
---
 build/Defaults/Net460/app.config              |  2 +-
 build/Defaults/Net462/app.config              |  2 +-
 build/Targets/Packages.props                  | 71 ++++++++---------
 .../Extension/CompilerExtension.csproj        |  3 +
 .../CSharp/CSharpEditorFeatures.csproj        |  2 +
 .../CSharpGoToDefinitionItemService.cs        | 16 ++++
 .../CSharpGoToDefinitionService.cs            |  5 --
 .../CSharpGoToDefinitionSymbolService.cs      | 20 +++++
 src/EditorFeatures/Core/EditorFeatures.csproj |  6 ++
 .../AbstractGoToDefinitionItemService.cs      | 48 ++++++++++++
 .../AbstractGoToDefinitionService.cs          | 33 +-------
 .../AbstractGoToDefinitionSymbolService.cs    | 35 +++++++++
 .../GoToDefinition/GoToDefinitionContext.cs   | 43 +++++++++++
 .../GoToDefinition/GoToDefinitionHelpers.cs   | 43 +++++++++--
 .../IGoToDefinitionSymbolService.cs           | 14 ++++
 .../Core/GoToDefinition/IGoToSymbolService.cs | 18 +++++
 .../WellKnownDefinitionTypes.cs               | 10 +++
 .../NavigableSymbolService.NavigableSymbol.cs | 61 +++++++++++++++
 ...ableSymbolService.NavigableSymbolSource.cs | 76 +++++++++++++++++++
 .../NavigableSymbolService.cs                 | 39 ++++++++++
 ...ntUncommentSelectionCommandHandlerTests.cs |  4 +-
 .../Test/Utilities/PatternMatcherTests.cs     |  4 +-
 .../NavigableSymbols/NavigableSymbolsTest.vb  | 73 ++++++++++++++++++
 .../TextEditorFactoryExtensions.cs            | 12 ++-
 .../Workspaces/TestHostDocument.cs            | 19 ++++-
 .../ServicesTestUtilities2.vbproj             |  1 +
 .../Utilities/GoToHelpers/GoToTestHelpers.vb  |  6 +-
 .../VisualBasic/BasicEditorFeatures.vbproj    |  2 +
 .../VisualBasicGoToDefinitionItemService.vb   | 11 +++
 .../VisualBasicGoToDefinitionService.vb       |  4 -
 .../VisualBasicGoToDefinitionSymbolService.vb | 18 +++++
 .../Core/Def/ServicesVisualStudio.csproj      |  3 +
 .../Next/ServicesVisualStudio.Next.csproj     |  6 ++
 .../Extensions/SemanticModelExtensions.cs     | 10 ++-
 34 files changed, 625 insertions(+), 95 deletions(-)
 create mode 100644 src/EditorFeatures/CSharp/GoToDefinition/CSharpGoToDefinitionItemService.cs
 create mode 100644 src/EditorFeatures/CSharp/GoToDefinition/CSharpGoToDefinitionSymbolService.cs
 create mode 100644 src/EditorFeatures/Core/GoToDefinition/AbstractGoToDefinitionItemService.cs
 create mode 100644 src/EditorFeatures/Core/GoToDefinition/AbstractGoToDefinitionSymbolService.cs
 create mode 100644 src/EditorFeatures/Core/GoToDefinition/GoToDefinitionContext.cs
 create mode 100644 src/EditorFeatures/Core/GoToDefinition/IGoToDefinitionSymbolService.cs
 create mode 100644 src/EditorFeatures/Core/GoToDefinition/IGoToSymbolService.cs
 create mode 100644 src/EditorFeatures/Core/GoToDefinition/WellKnownDefinitionTypes.cs
 create mode 100644 src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.NavigableSymbol.cs
 create mode 100644 src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.NavigableSymbolSource.cs
 create mode 100644 src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.cs
 create mode 100644 src/EditorFeatures/Test2/NavigableSymbols/NavigableSymbolsTest.vb
 create mode 100644 src/EditorFeatures/VisualBasic/GoToDefinition/VisualBasicGoToDefinitionItemService.vb
 create mode 100644 src/EditorFeatures/VisualBasic/GoToDefinition/VisualBasicGoToDefinitionSymbolService.vb

diff --git a/build/Defaults/Net460/app.config b/build/Defaults/Net460/app.config
index 8db45c0c5c11b..5194a2fa0a970 100644
--- a/build/Defaults/Net460/app.config
+++ b/build/Defaults/Net460/app.config
@@ -75,7 +75,7 @@
       </dependentAssembly>
       <dependentAssembly>
         <assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" culture="neutral"/>
-        <bindingRedirect oldVersion="0.0.0.0-8.0.0.0" newVersion="8.0.0.0"/>
+        <bindingRedirect oldVersion="0.0.0.0-9.0.0.0" newVersion="9.0.0.0"/>
       </dependentAssembly>
 
       <!-- Even though all of our references are to Dev15 binaries we are still pulling in BasicUndo
diff --git a/build/Defaults/Net462/app.config b/build/Defaults/Net462/app.config
index 65a0c73b38b43..7f9cf2c4f51d1 100644
--- a/build/Defaults/Net462/app.config
+++ b/build/Defaults/Net462/app.config
@@ -83,7 +83,7 @@
       </dependentAssembly>
       <dependentAssembly>
         <assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" culture="neutral"/>
-        <bindingRedirect oldVersion="0.0.0.0-8.0.0.0" newVersion="8.0.0.0"/>
+        <bindingRedirect oldVersion="0.0.0.0-9.0.0.0" newVersion="9.0.0.0"/>
       </dependentAssembly>
 
       <!-- Even though all of our references are to Dev15 binaries we are still pulling in BasicUndo
diff --git a/build/Targets/Packages.props b/build/Targets/Packages.props
index 6833448bd7223..b4d06c6a6b167 100644
--- a/build/Targets/Packages.props
+++ b/build/Targets/Packages.props
@@ -41,7 +41,7 @@
     <MicrosoftDiaSymReaderPortablePdbVersion>1.3.0</MicrosoftDiaSymReaderPortablePdbVersion>
     <MicrosoftDotNetIBCMerge>4.7.2-alpha-00001</MicrosoftDotNetIBCMerge>
     <MicrosoftIdentityModelClientsActiveDirectoryVersion>3.13.8</MicrosoftIdentityModelClientsActiveDirectoryVersion>
-    <MicrosoftInternalPerformanceCodeMarkersDesignTimeVersion>15.0.26507-alpha</MicrosoftInternalPerformanceCodeMarkersDesignTimeVersion>
+    <MicrosoftInternalPerformanceCodeMarkersDesignTimeVersion>15.0.26606-alpha</MicrosoftInternalPerformanceCodeMarkersDesignTimeVersion>
     <MicrosoftInternalVisualStudioShellInterop140DesignTimeVersion>14.3.25407-alpha</MicrosoftInternalVisualStudioShellInterop140DesignTimeVersion>
     <MicrosoftMetadataVisualizerVersion>1.0.0-beta1-61531-03</MicrosoftMetadataVisualizerVersion>
     <MicrosoftMSXMLVersion>8.0.0.0-alpha</MicrosoftMSXMLVersion>
@@ -60,35 +60,35 @@
     <MicrosoftNetSdkVersion>2.0.0-alpha-20170405-2</MicrosoftNetSdkVersion>
     <MicrosoftNuGetBuildTasksVersion>0.1.0</MicrosoftNuGetBuildTasksVersion>
     <MicrosoftPortableTargetsVersion>0.1.2-dev</MicrosoftPortableTargetsVersion>
-    <MicrosoftServiceHubClientVersion>1.1.18-rc-g92b2150dd1</MicrosoftServiceHubClientVersion>
+    <MicrosoftServiceHubClientVersion>1.1.31-rc</MicrosoftServiceHubClientVersion>
     <MicrosoftTplDataflowVersion>4.5.24</MicrosoftTplDataflowVersion>
     <MicrosoftVisualBasicVersion>10.1.0</MicrosoftVisualBasicVersion>
-    <MicrosoftVisualStudioCallHierarchyPackageDefinitionsVersion>15.0.26507-alpha</MicrosoftVisualStudioCallHierarchyPackageDefinitionsVersion>
-    <MicrosoftVisualStudioCodeAnalysisSdkUIVersion>15.0.26507-alpha</MicrosoftVisualStudioCodeAnalysisSdkUIVersion>
-    <MicrosoftVisualStudioComponentModelHostVersion>15.0.26507-alpha</MicrosoftVisualStudioComponentModelHostVersion>
+    <MicrosoftVisualStudioCallHierarchyPackageDefinitionsVersion>15.0.26606-alpha</MicrosoftVisualStudioCallHierarchyPackageDefinitionsVersion>
+    <MicrosoftVisualStudioCodeAnalysisSdkUIVersion>15.0.26606-alpha</MicrosoftVisualStudioCodeAnalysisSdkUIVersion>
+    <MicrosoftVisualStudioComponentModelHostVersion>15.0.26606-alpha</MicrosoftVisualStudioComponentModelHostVersion>
     <MicrosoftVisualStudioCompositionVersion>15.0.66-rc</MicrosoftVisualStudioCompositionVersion>
-    <MicrosoftVisualStudioCoreUtilityVersion>15.0.26507-alpha</MicrosoftVisualStudioCoreUtilityVersion>
+    <MicrosoftVisualStudioCoreUtilityVersion>15.0.26606-alpha</MicrosoftVisualStudioCoreUtilityVersion>
     <MicrosoftVisualStudioDebuggerEngineVersion>15.0.26201-gamma</MicrosoftVisualStudioDebuggerEngineVersion>
     <MicrosoftVisualStudioDebuggerMetadataVersion>15.0.26201-gamma</MicrosoftVisualStudioDebuggerMetadataVersion>
     <MicrosoftVisualStudioDebuggerInterop100Version>10.0.30319</MicrosoftVisualStudioDebuggerInterop100Version>
     <MicrosoftVisualStudioDesignerInterfacesVersion>1.1.4322</MicrosoftVisualStudioDesignerInterfacesVersion>
-    <MicrosoftVisualStudioDiagnosticsPerformanceProviderVersion>15.0.26507-alpha</MicrosoftVisualStudioDiagnosticsPerformanceProviderVersion>
-    <MicrosoftVisualStudioEditorVersion>15.0.26507-alpha</MicrosoftVisualStudioEditorVersion>
-    <MicrosoftVisualStudioGraphModelVersion>15.0.26507-alpha</MicrosoftVisualStudioGraphModelVersion>
-    <MicrosoftVisualStudioImageCatalogVersion>15.0.26507-alpha</MicrosoftVisualStudioImageCatalogVersion>
-    <MicrosoftVisualStudioImagingVersion>15.0.26507-alpha</MicrosoftVisualStudioImagingVersion>
+    <MicrosoftVisualStudioDiagnosticsPerformanceProviderVersion>15.0.26606-alpha</MicrosoftVisualStudioDiagnosticsPerformanceProviderVersion>
+    <MicrosoftVisualStudioEditorVersion>15.0.26606-alpha</MicrosoftVisualStudioEditorVersion>
+    <MicrosoftVisualStudioGraphModelVersion>15.0.26606-alpha</MicrosoftVisualStudioGraphModelVersion>
+    <MicrosoftVisualStudioImageCatalogVersion>15.0.26606-alpha</MicrosoftVisualStudioImageCatalogVersion>
+    <MicrosoftVisualStudioImagingVersion>15.0.26606-alpha</MicrosoftVisualStudioImagingVersion>
     <MicrosoftVisualStudioImagingInterop140DesignTimeVersion>14.3.25407</MicrosoftVisualStudioImagingInterop140DesignTimeVersion>
     <MicrosoftVisualStudioInteractiveWindowVersion>2.0.0-rc3-61304-01</MicrosoftVisualStudioInteractiveWindowVersion>
-    <MicrosoftVisualStudioLanguageCallHierarchyVersion>15.0.26507-alpha</MicrosoftVisualStudioLanguageCallHierarchyVersion>
-    <MicrosoftVisualStudioLanguageIntellisenseVersion>15.0.26507-alpha</MicrosoftVisualStudioLanguageIntellisenseVersion>
-    <MicrosoftVisualStudioLanguageNavigateToInterfacesVersion>15.0.26507-alpha</MicrosoftVisualStudioLanguageNavigateToInterfacesVersion>
-    <MicrosoftVisualStudioLanguageStandardClassificationVersion>15.0.26507-alpha</MicrosoftVisualStudioLanguageStandardClassificationVersion>
+    <MicrosoftVisualStudioLanguageCallHierarchyVersion>15.0.26606-alpha</MicrosoftVisualStudioLanguageCallHierarchyVersion>
+    <MicrosoftVisualStudioLanguageIntellisenseVersion>15.0.26606-alpha</MicrosoftVisualStudioLanguageIntellisenseVersion>
+    <MicrosoftVisualStudioLanguageNavigateToInterfacesVersion>15.0.26606-alpha</MicrosoftVisualStudioLanguageNavigateToInterfacesVersion>
+    <MicrosoftVisualStudioLanguageStandardClassificationVersion>15.0.26606-alpha</MicrosoftVisualStudioLanguageStandardClassificationVersion>
     <MicrosoftVisualStudioOLEInteropVersion>7.10.6070</MicrosoftVisualStudioOLEInteropVersion>
-    <MicrosoftVisualStudioPlatformVSEditorVersion>15.0.26507-alpha</MicrosoftVisualStudioPlatformVSEditorVersion>
-    <MicrosoftVisualStudioPlatformVSEditorInteropVersion>15.0.26507-alpha</MicrosoftVisualStudioPlatformVSEditorInteropVersion>
-    <MicrosoftVisualStudioProgressionCodeSchemaVersion>15.0.26507-alpha</MicrosoftVisualStudioProgressionCodeSchemaVersion>
-    <MicrosoftVisualStudioProgressionCommonVersion>15.0.26507-alpha</MicrosoftVisualStudioProgressionCommonVersion>
-    <MicrosoftVisualStudioProgressionInterfacesVersion>15.0.26507-alpha</MicrosoftVisualStudioProgressionInterfacesVersion>
+    <MicrosoftVisualStudioPlatformVSEditorVersion>15.0.26606-alpha</MicrosoftVisualStudioPlatformVSEditorVersion>
+    <MicrosoftVisualStudioPlatformVSEditorInteropVersion>15.0.26606-alpha</MicrosoftVisualStudioPlatformVSEditorInteropVersion>
+    <MicrosoftVisualStudioProgressionCodeSchemaVersion>15.0.26606-alpha</MicrosoftVisualStudioProgressionCodeSchemaVersion>
+    <MicrosoftVisualStudioProgressionCommonVersion>15.0.26606-alpha</MicrosoftVisualStudioProgressionCommonVersion>
+    <MicrosoftVisualStudioProgressionInterfacesVersion>15.0.26606-alpha</MicrosoftVisualStudioProgressionInterfacesVersion>
     <MicrosoftVisualStudioProjectSystemVersion>15.3.178-pre-g209fb07c2e</MicrosoftVisualStudioProjectSystemVersion>
     <MicrosoftVisualStudioQualityToolsUnitTestFrameworkVersion>10.0.0.0-alpha</MicrosoftVisualStudioQualityToolsUnitTestFrameworkVersion>
     <MicrosoftVisualStudioRemoteControlVersion>14.0.249-master2E2DC10C</MicrosoftVisualStudioRemoteControlVersion>
@@ -96,32 +96,33 @@
     <MicrosoftVisualStudioSetupConfigurationNativex86Version>1.3.269-rc</MicrosoftVisualStudioSetupConfigurationNativex86Version>
     <MicrosoftVisualStudioSettings140Version>14.3.25407</MicrosoftVisualStudioSettings140Version>
     <MicrosoftVisualStudioShell140Version>14.3.25407</MicrosoftVisualStudioShell140Version>
-    <MicrosoftVisualStudioShell150Version>15.0.26507-alpha</MicrosoftVisualStudioShell150Version>
-    <MicrosoftVisualStudioShellDesignVersion>15.0.26507-alpha</MicrosoftVisualStudioShellDesignVersion>
-    <MicrosoftVisualStudioShellFrameworkVersion>15.0.26507-alpha</MicrosoftVisualStudioShellFrameworkVersion>
-    <MicrosoftVisualStudioShellImmutable100Version>15.0.26507-alpha</MicrosoftVisualStudioShellImmutable100Version>
+    <MicrosoftVisualStudioShell150Version>15.0.26606-alpha</MicrosoftVisualStudioShell150Version>
+    <MicrosoftVisualStudioShellDesignVersion>15.0.26606-alpha</MicrosoftVisualStudioShellDesignVersion>
+	  <MicrosoftVisualStudioShellInterop153DesignTimeVersion>15.0.26606-alpha</MicrosoftVisualStudioShellInterop153DesignTimeVersion>
+    <MicrosoftVisualStudioShellFrameworkVersion>15.0.26606-alpha</MicrosoftVisualStudioShellFrameworkVersion>
+    <MicrosoftVisualStudioShellImmutable100Version>15.0.26606-alpha</MicrosoftVisualStudioShellImmutable100Version>
     <MicrosoftVisualStudioShellImmutable110Version>15.0.25413-Preview5</MicrosoftVisualStudioShellImmutable110Version>
     <MicrosoftVisualStudioShellInteropVersion>7.10.6071</MicrosoftVisualStudioShellInteropVersion>
     <MicrosoftVisualStudioShellInterop100Version>10.0.30319</MicrosoftVisualStudioShellInterop100Version>
     <MicrosoftVisualStudioShellInterop110Version>11.0.61030</MicrosoftVisualStudioShellInterop110Version>
     <MicrosoftVisualStudioShellInterop121DesignTimeVersion>12.1.30328</MicrosoftVisualStudioShellInterop121DesignTimeVersion>
     <MicrosoftVisualStudioShellInterop140DesignTimeVersion>14.3.25407</MicrosoftVisualStudioShellInterop140DesignTimeVersion>
-    <MicrosoftVisualStudioShellInterop150DesignTimeVersion>15.0.26507-alpha</MicrosoftVisualStudioShellInterop150DesignTimeVersion>
+    <MicrosoftVisualStudioShellInterop150DesignTimeVersion>15.0.26606-alpha</MicrosoftVisualStudioShellInterop150DesignTimeVersion>
     <MicrosoftVisualStudioShellInterop80Version>8.0.50727</MicrosoftVisualStudioShellInterop80Version>
     <MicrosoftVisualStudioShellInterop90Version>9.0.30729</MicrosoftVisualStudioShellInterop90Version>
-    <MicrosoftVisualStudioTelemetryVersion>15.0.26507-alpha</MicrosoftVisualStudioTelemetryVersion>
+    <MicrosoftVisualStudioTelemetryVersion>15.0.26606-alpha</MicrosoftVisualStudioTelemetryVersion>
     <MicrosoftVisualStudioTemplateWizardInterfaceVersion>8.0.0.0-alpha</MicrosoftVisualStudioTemplateWizardInterfaceVersion>
-    <MicrosoftVisualStudioTextDataVersion>15.0.26507-alpha</MicrosoftVisualStudioTextDataVersion>
-    <MicrosoftVisualStudioTextInternalVersion>15.0.26507-alpha</MicrosoftVisualStudioTextInternalVersion>
-    <MicrosoftVisualStudioTextLogicVersion>15.0.26507-alpha</MicrosoftVisualStudioTextLogicVersion>
-    <MicrosoftVisualStudioTextUIVersion>15.0.26507-alpha</MicrosoftVisualStudioTextUIVersion>
-    <MicrosoftVisualStudioTextUIWpfVersion>15.0.26507-alpha</MicrosoftVisualStudioTextUIWpfVersion>
+    <MicrosoftVisualStudioTextDataVersion>15.0.26606-alpha</MicrosoftVisualStudioTextDataVersion>
+    <MicrosoftVisualStudioTextInternalVersion>15.0.26606-alpha</MicrosoftVisualStudioTextInternalVersion>
+    <MicrosoftVisualStudioTextLogicVersion>15.0.26606-alpha</MicrosoftVisualStudioTextLogicVersion>
+    <MicrosoftVisualStudioTextUIVersion>15.0.26606-alpha</MicrosoftVisualStudioTextUIVersion>
+    <MicrosoftVisualStudioTextUIWpfVersion>15.0.26606-alpha</MicrosoftVisualStudioTextUIWpfVersion>
     <MicrosoftVisualStudioTextManagerInteropVersion>7.10.6070</MicrosoftVisualStudioTextManagerInteropVersion>
     <MicrosoftVisualStudioTextManagerInterop100Version>10.0.30319</MicrosoftVisualStudioTextManagerInterop100Version>
     <MicrosoftVisualStudioTextManagerInterop120Version>12.0.30110</MicrosoftVisualStudioTextManagerInterop120Version>
     <MicrosoftVisualStudioTextManagerInterop121DesignTimeVersion>12.1.30328</MicrosoftVisualStudioTextManagerInterop121DesignTimeVersion>
     <MicrosoftVisualStudioThreadingVersion>15.3.20</MicrosoftVisualStudioThreadingVersion>
-    <MicrosoftVisualStudioUtilitiesVersion>15.0.26507-alpha</MicrosoftVisualStudioUtilitiesVersion>
+    <MicrosoftVisualStudioUtilitiesVersion>15.0.26606-alpha</MicrosoftVisualStudioUtilitiesVersion>
     <MicrosoftVisualStudioValidationVersion>15.3.15</MicrosoftVisualStudioValidationVersion>
     <MicrosoftVisualStudioVsInteractiveWindowVersion>2.0.0-rc3-61304-01</MicrosoftVisualStudioVsInteractiveWindowVersion>
     <MicrosoftWin32PrimitivesVersion>4.3.0</MicrosoftWin32PrimitivesVersion>
@@ -130,7 +131,7 @@
     <MoqVersion>4.2.1402.2112</MoqVersion>
     <NerdbankFullDuplexStreamVersion>1.0.1</NerdbankFullDuplexStreamVersion>
     <NETStandardLibraryVersion>1.6.1</NETStandardLibraryVersion>
-    <NewtonsoftJsonVersion>8.0.3</NewtonsoftJsonVersion>
+    <NewtonsoftJsonVersion>9.0.1</NewtonsoftJsonVersion>
     <NuGetCommandLineVersion>2.8.5</NuGetCommandLineVersion>
     <NuGetCommandLineXPlatVersion>3.5.0-beta2-1484</NuGetCommandLineXPlatVersion>
     <NuGetVisualStudioVersion>4.0.0-rc-2048</NuGetVisualStudioVersion>
@@ -145,7 +146,7 @@
     <RoslynToolsMicrosoftVSIXExpInstallerVersion>0.4.0-beta</RoslynToolsMicrosoftVSIXExpInstallerVersion>
     <RoslynToolsReferenceAssembliesVersion>0.1.1</RoslynToolsReferenceAssembliesVersion>
     <RoslynMicrosoftVisualStudioExtensionManagerVersion>0.0.4</RoslynMicrosoftVisualStudioExtensionManagerVersion>
-    <StreamJsonRpcVersion>1.0.2-rc</StreamJsonRpcVersion>
+    <StreamJsonRpcVersion>1.1.73</StreamJsonRpcVersion>
     <SystemAppContextVersion>4.3.0</SystemAppContextVersion>
     <SystemCollectionsVersion>4.3.0</SystemCollectionsVersion>
     <SystemCollectionsConcurrentVersion>4.3.0</SystemCollectionsConcurrentVersion>
@@ -228,4 +229,4 @@
     <xunitrunnervisualstudioVersion>2.2.0-beta4-build1194</xunitrunnervisualstudioVersion>
   </PropertyGroup>
 
-</Project>
+</Project>
\ No newline at end of file
diff --git a/src/Compilers/Extension/CompilerExtension.csproj b/src/Compilers/Extension/CompilerExtension.csproj
index ee0f23cc2b85a..f42791562d849 100644
--- a/src/Compilers/Extension/CompilerExtension.csproj
+++ b/src/Compilers/Extension/CompilerExtension.csproj
@@ -171,6 +171,9 @@
     <PackageReference Include="Microsoft.VisualStudio.Utilities">
       <Version>$(MicrosoftVisualStudioUtilitiesVersion)</Version>
     </PackageReference>
+	<PackageReference Include="Microsoft.VisualStudio.Shell.Interop.15.3.DesignTime">
+		<Version>$(MicrosoftVisualStudioShellInterop153DesignTimeVersion)</Version>
+	</PackageReference>
   </ItemGroup>
   <Import Project="..\..\..\build\Targets\Imports.targets" />
 </Project>
diff --git a/src/EditorFeatures/CSharp/CSharpEditorFeatures.csproj b/src/EditorFeatures/CSharp/CSharpEditorFeatures.csproj
index 4369095c0de14..eebe79e1fb799 100644
--- a/src/EditorFeatures/CSharp/CSharpEditorFeatures.csproj
+++ b/src/EditorFeatures/CSharp/CSharpEditorFeatures.csproj
@@ -116,7 +116,9 @@
     <Compile Include="Formatting\Indentation\SmartTokenFormatterCommandHandler.cs" />
     <Compile Include="Formatting\Indentation\WhitespaceExtensions.cs" />
     <Compile Include="Formatting\CSharpEditorFormattingService.PasteFormattingRule.cs" />
+    <Compile Include="GoToDefinition\CSharpGoToDefinitionItemService.cs" />
     <Compile Include="GoToDefinition\CSharpGoToDefinitionService.cs" />
+    <Compile Include="GoToDefinition\CSharpGoToDefinitionSymbolService.cs" />
     <Compile Include="Highlighting\KeywordHighlighters\AbstractAsyncHighlighter.cs" />
     <Compile Include="Highlighting\KeywordHighlighters\AsyncAnonymousMethodHighlighter.cs" />
     <Compile Include="Highlighting\KeywordHighlighters\AsyncMethodHighlighter.cs" />
diff --git a/src/EditorFeatures/CSharp/GoToDefinition/CSharpGoToDefinitionItemService.cs b/src/EditorFeatures/CSharp/GoToDefinition/CSharpGoToDefinitionItemService.cs
new file mode 100644
index 0000000000000..40548e25f498d
--- /dev/null
+++ b/src/EditorFeatures/CSharp/GoToDefinition/CSharpGoToDefinitionItemService.cs
@@ -0,0 +1,16 @@
+using System;
+using System.Collections.Generic;
+using System.Composition;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using Microsoft.CodeAnalysis.Editor.GoToDefinition;
+using Microsoft.CodeAnalysis.Host.Mef;
+
+namespace Microsoft.CodeAnalysis.Editor.CSharp.GoToDefinition
+{
+    [ExportLanguageService(typeof(IGoToSymbolService), LanguageNames.CSharp), Shared]
+    internal class CSharpGoToDefinitionItemService : AbstractGoToDefinitionItemService
+    {
+    }
+}
diff --git a/src/EditorFeatures/CSharp/GoToDefinition/CSharpGoToDefinitionService.cs b/src/EditorFeatures/CSharp/GoToDefinition/CSharpGoToDefinitionService.cs
index 8df42b4b440b4..b58b6ccfd5c9d 100644
--- a/src/EditorFeatures/CSharp/GoToDefinition/CSharpGoToDefinitionService.cs
+++ b/src/EditorFeatures/CSharp/GoToDefinition/CSharpGoToDefinitionService.cs
@@ -18,10 +18,5 @@ internal class CSharpGoToDefinitionService : AbstractGoToDefinitionService
             : base(streamingPresenters)
         {
         }
-
-        protected override ISymbol FindRelatedExplicitlyDeclaredSymbol(ISymbol symbol, Compilation compilation)
-        {
-            return symbol;
-        }
     }
 }
\ No newline at end of file
diff --git a/src/EditorFeatures/CSharp/GoToDefinition/CSharpGoToDefinitionSymbolService.cs b/src/EditorFeatures/CSharp/GoToDefinition/CSharpGoToDefinitionSymbolService.cs
new file mode 100644
index 0000000000000..d87c74057b0eb
--- /dev/null
+++ b/src/EditorFeatures/CSharp/GoToDefinition/CSharpGoToDefinitionSymbolService.cs
@@ -0,0 +1,20 @@
+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Composition;
+using Microsoft.CodeAnalysis.Editor.GoToDefinition;
+using Microsoft.CodeAnalysis.Editor.Host;
+using Microsoft.CodeAnalysis.Host.Mef;
+
+namespace Microsoft.CodeAnalysis.Editor.CSharp.GoToDefinition
+{
+    [ExportLanguageService(typeof(IGoToDefinitionSymbolService), LanguageNames.CSharp), Shared]
+    internal class CSharpGoToDefinitionSymbolService : AbstractGoToDefinitionSymbolService
+    {
+        protected override ISymbol FindRelatedExplicitlyDeclaredSymbol(ISymbol symbol, Compilation compilation)
+        {
+            return symbol;
+        }
+    }
+}
diff --git a/src/EditorFeatures/Core/EditorFeatures.csproj b/src/EditorFeatures/Core/EditorFeatures.csproj
index db68ede2853f5..304c7df634c70 100644
--- a/src/EditorFeatures/Core/EditorFeatures.csproj
+++ b/src/EditorFeatures/Core/EditorFeatures.csproj
@@ -161,6 +161,12 @@
     <Compile Include="FindUsages\IFindUsagesContext.cs" />
     <Compile Include="FindUsages\IFindUsagesService.cs" />
     <Compile Include="FindUsages\SimpleFindUsagesContext.cs" />
+    <Compile Include="GoToDefinition\AbstractGoToDefinitionItemService.cs" />
+    <Compile Include="GoToDefinition\AbstractGoToDefinitionSymbolService.cs" />
+    <Compile Include="GoToDefinition\GoToDefinitionContext.cs" />
+    <Compile Include="GoToDefinition\IGoToDefinitionSymbolService.cs" />
+    <Compile Include="GoToDefinition\IGoToSymbolService.cs" />
+    <Compile Include="GoToDefinition\WellKnownDefinitionTypes.cs" />
     <Compile Include="Implementation\InlineRename\Dashboard\DashboardAutomationPeer.cs" />
     <Compile Include="Implementation\InlineRename\HighlightTags\RenameConflictTag.cs" />
     <Compile Include="Implementation\InlineRename\HighlightTags\RenameConflictTagDefinition.cs" />
diff --git a/src/EditorFeatures/Core/GoToDefinition/AbstractGoToDefinitionItemService.cs b/src/EditorFeatures/Core/GoToDefinition/AbstractGoToDefinitionItemService.cs
new file mode 100644
index 0000000000000..7b74101ecab65
--- /dev/null
+++ b/src/EditorFeatures/Core/GoToDefinition/AbstractGoToDefinitionItemService.cs
@@ -0,0 +1,48 @@
+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using System.Collections.Immutable;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.CodeAnalysis.Editor.FindUsages;
+using Microsoft.CodeAnalysis.Editor.Shared.Utilities;
+using Microsoft.CodeAnalysis.FindUsages;
+using Microsoft.CodeAnalysis.Host.Mef;
+using Microsoft.CodeAnalysis.Shared.Extensions;
+
+namespace Microsoft.CodeAnalysis.Editor.GoToDefinition
+{
+    internal abstract class AbstractGoToDefinitionItemService : ForegroundThreadAffinitizedObject, IGoToSymbolService
+    {
+        public async Task GetDefinitionsAsync(GoToDefinitionContext context)
+        {
+            var document = context.Document;
+            var position = context.Position;
+            var cancellationToken = context.CancellationToken;
+
+            var service = document.GetLanguageService<IGoToDefinitionSymbolService>();
+            var (symbol, span) = await service.GetSymbolAndBoundSpanAsync(document, position, cancellationToken).ConfigureAwait(false);
+
+            if (symbol == null)
+            {
+                return;
+            }
+
+            // We want ctrl-click GTD to be as close to regular GTD as possible.
+            // This means we have to query for "third party navigation", from
+            // XAML, etc. That call has to be done on the UI thread.
+            var definitions = await Task.Factory.StartNew(() =>
+                GoToDefinitionHelpers.GetDefinitions(symbol, document.Project, thirdPartyNavigationAllowed: true, cancellationToken: cancellationToken)
+                .WhereAsArray(d => d.CanNavigateTo(document.Project.Solution.Workspace)),
+                cancellationToken,
+                TaskCreationOptions.None,
+                ForegroundTaskScheduler).ConfigureAwait(false);
+
+            foreach (var definition in definitions)
+            {
+                context.AddItem(WellKnownDefinitionTypes.Definition, definition);
+            }
+
+            context.Span = span;
+        }
+    }
+}
diff --git a/src/EditorFeatures/Core/GoToDefinition/AbstractGoToDefinitionService.cs b/src/EditorFeatures/Core/GoToDefinition/AbstractGoToDefinitionService.cs
index e96091c18688b..0181b7c8ef9a7 100644
--- a/src/EditorFeatures/Core/GoToDefinition/AbstractGoToDefinitionService.cs
+++ b/src/EditorFeatures/Core/GoToDefinition/AbstractGoToDefinitionService.cs
@@ -6,7 +6,6 @@
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.Editor.Host;
-using Microsoft.CodeAnalysis.FindSymbols;
 using Microsoft.CodeAnalysis.LanguageServices;
 using Microsoft.CodeAnalysis.Navigation;
 using Microsoft.CodeAnalysis.Shared.Extensions;
@@ -18,42 +17,17 @@ internal abstract class AbstractGoToDefinitionService : IGoToDefinitionService
     {
         private readonly IEnumerable<Lazy<IStreamingFindUsagesPresenter>> _streamingPresenters;
 
-        protected abstract ISymbol FindRelatedExplicitlyDeclaredSymbol(ISymbol symbol, Compilation compilation);
-
         protected AbstractGoToDefinitionService(
             IEnumerable<Lazy<IStreamingFindUsagesPresenter>> streamingPresenters)
         {
             _streamingPresenters = streamingPresenters;
         }
 
-        private async Task<ISymbol> FindSymbolAsync(Document document, int position, CancellationToken cancellationToken)
-        {
-            if (!document.SupportsSemanticModel)
-            {
-                return null;
-            }
-
-            var workspace = document.Project.Solution.Workspace;
-
-            var semanticModel = await document.GetSemanticModelAsync(cancellationToken).ConfigureAwait(false);
-            var semanticInfo = await SymbolFinder.GetSemanticInfoAtPositionAsync(semanticModel, position, workspace, cancellationToken).ConfigureAwait(false);
-
-            // prefer references to declarations.  It's more likely that the user is attempting to 
-            // go to a definition at some other location, rather than the definition they're on.  
-            // This can happen when a token is at a location that is both a reference and a definition.
-            // For example, on an anonymous type member declaration.
-            var symbol = semanticInfo.AliasSymbol ??
-                         semanticInfo.ReferencedSymbols.FirstOrDefault() ??
-                         semanticInfo.DeclaredSymbol ??
-                         semanticInfo.Type;
-
-            return FindRelatedExplicitlyDeclaredSymbol(symbol, semanticModel.Compilation);
-        }
-
         public async Task<IEnumerable<INavigableItem>> FindDefinitionsAsync(
             Document document, int position, CancellationToken cancellationToken)
         {
-            var symbol = await FindSymbolAsync(document, position, cancellationToken).ConfigureAwait(false);
+            var symbolService = document.GetLanguageService<IGoToDefinitionSymbolService>();
+            var (symbol, span) = await symbolService.GetSymbolAndBoundSpanAsync(document, position, cancellationToken).ConfigureAwait(false);
 
             // Try to compute source definitions from symbol.
             var items = symbol != null
@@ -68,7 +42,8 @@ private async Task<ISymbol> FindSymbolAsync(Document document, int position, Can
         public bool TryGoToDefinition(Document document, int position, CancellationToken cancellationToken)
         {
             // First try to compute the referenced symbol and attempt to go to definition for the symbol.
-            var symbol = FindSymbolAsync(document, position, cancellationToken).WaitAndGetResult(cancellationToken);
+            var symbolService = document.GetLanguageService<IGoToDefinitionSymbolService>();
+            var (symbol, span) = symbolService.GetSymbolAndBoundSpanAsync(document, position, cancellationToken).WaitAndGetResult(cancellationToken);
             if (symbol == null)
             {
                 return false;
diff --git a/src/EditorFeatures/Core/GoToDefinition/AbstractGoToDefinitionSymbolService.cs b/src/EditorFeatures/Core/GoToDefinition/AbstractGoToDefinitionSymbolService.cs
new file mode 100644
index 0000000000000..ef984af83835c
--- /dev/null
+++ b/src/EditorFeatures/Core/GoToDefinition/AbstractGoToDefinitionSymbolService.cs
@@ -0,0 +1,35 @@
+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.CodeAnalysis.FindSymbols;
+using Microsoft.CodeAnalysis.Host;
+using Microsoft.CodeAnalysis.Text;
+
+namespace Microsoft.CodeAnalysis.Editor.GoToDefinition
+{
+    internal abstract class AbstractGoToDefinitionSymbolService : IGoToDefinitionSymbolService
+    {
+        protected abstract ISymbol FindRelatedExplicitlyDeclaredSymbol(ISymbol symbol, Compilation compilation);
+
+        public async Task<(ISymbol, TextSpan)> GetSymbolAndBoundSpanAsync(Document document, int position, CancellationToken cancellationToken)
+        {
+            var workspace = document.Project.Solution.Workspace;
+
+            var semanticModel = await document.GetSemanticModelAsync(cancellationToken).ConfigureAwait(false);
+            var semanticInfo = await SymbolFinder.GetSemanticInfoAtPositionAsync(semanticModel, position, workspace, cancellationToken).ConfigureAwait(false);
+
+            // prefer references to declarations.  It's more likely that the user is attempting to 
+            // go to a definition at some other location, rather than the definition they're on.  
+            // This can happen when a token is at a location that is both a reference and a definition.
+            // For example, on an anonymous type member declaration.
+            var symbol = semanticInfo.AliasSymbol ??
+                         semanticInfo.ReferencedSymbols.FirstOrDefault() ??
+                         semanticInfo.DeclaredSymbol ??
+                         semanticInfo.Type;
+
+            return (FindRelatedExplicitlyDeclaredSymbol(symbol, semanticModel.Compilation), semanticInfo.Span);
+        }
+    }
+}
diff --git a/src/EditorFeatures/Core/GoToDefinition/GoToDefinitionContext.cs b/src/EditorFeatures/Core/GoToDefinition/GoToDefinitionContext.cs
new file mode 100644
index 0000000000000..40f576903bf65
--- /dev/null
+++ b/src/EditorFeatures/Core/GoToDefinition/GoToDefinitionContext.cs
@@ -0,0 +1,43 @@
+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using System.Collections.Generic;
+using System.Threading;
+using Microsoft.CodeAnalysis.FindUsages;
+using Microsoft.CodeAnalysis.Text;
+
+namespace Microsoft.CodeAnalysis.Editor.GoToDefinition
+{
+    internal class GoToDefinitionContext
+    {
+        private readonly object _gate = new object();
+
+        private readonly Dictionary<string, List<DefinitionItem>> _items = new Dictionary<string, List<DefinitionItem>>();
+
+        public GoToDefinitionContext(Document document, int position, CancellationToken cancellationToken)
+        {
+            Document = document;
+            Position = position;
+            CancellationToken = cancellationToken;
+        }
+
+        public Document Document { get; }
+        public int Position { get; }
+        public CancellationToken CancellationToken { get; }
+
+        public IReadOnlyDictionary<string, List<DefinitionItem>> Items => _items;
+        public TextSpan Span { get; set; }
+
+        public void AddItem(string key, DefinitionItem item)
+        {
+            lock (_gate)
+            {
+                if (!_items.ContainsKey(key))
+                {
+                    _items[key] = new List<DefinitionItem>();
+                }
+
+                _items[key].Add(item);
+            }
+        }
+    }
+}
diff --git a/src/EditorFeatures/Core/GoToDefinition/GoToDefinitionHelpers.cs b/src/EditorFeatures/Core/GoToDefinition/GoToDefinitionHelpers.cs
index fc576377d1294..613fa7a604766 100644
--- a/src/EditorFeatures/Core/GoToDefinition/GoToDefinitionHelpers.cs
+++ b/src/EditorFeatures/Core/GoToDefinition/GoToDefinitionHelpers.cs
@@ -2,6 +2,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Collections.Immutable;
 using System.Linq;
 using System.Threading;
 using Microsoft.CodeAnalysis.Editor.FindUsages;
@@ -15,13 +16,11 @@ namespace Microsoft.CodeAnalysis.Editor.GoToDefinition
 {
     internal static class GoToDefinitionHelpers
     {
-        public static bool TryGoToDefinition(
+        public static ImmutableArray<DefinitionItem> GetDefinitions(
             ISymbol symbol,
             Project project,
-            IEnumerable<Lazy<IStreamingFindUsagesPresenter>> streamingPresenters,
-            CancellationToken cancellationToken,
-            bool thirdPartyNavigationAllowed = true,
-            bool throwOnHiddenDefinition = false)
+            bool thirdPartyNavigationAllowed,
+            CancellationToken cancellationToken)
         {
             var alias = symbol as IAliasSymbol;
             if (alias != null)
@@ -29,7 +28,7 @@ internal static class GoToDefinitionHelpers
                 var ns = alias.Target as INamespaceSymbol;
                 if (ns != null && ns.IsGlobalNamespace)
                 {
-                    return false;
+                    return ImmutableArray.Create<DefinitionItem>();
                 }
             }
 
@@ -91,13 +90,43 @@ internal static class GoToDefinitionHelpers
             }
 
             definitions.Add(definitionItem);
+            return definitions.ToImmutableAndFree();
+        }
+
+        public static bool TryGoToDefinition(
+            ISymbol symbol,
+            Project project,
+            IEnumerable<Lazy<IStreamingFindUsagesPresenter>> streamingPresenters,
+            CancellationToken cancellationToken,
+            bool thirdPartyNavigationAllowed = true,
+            bool throwOnHiddenDefinition = false)
+        {
+            var definitions = GetDefinitions(symbol, project, thirdPartyNavigationAllowed, cancellationToken);
 
             var presenter = streamingPresenters.FirstOrDefault()?.Value;
             var title = string.Format(EditorFeaturesResources._0_declarations,
                 FindUsagesHelpers.GetDisplayName(symbol));
 
             return presenter.TryNavigateToOrPresentItemsAsync(
-                project.Solution.Workspace, title, definitions.ToImmutableAndFree()).WaitAndGetResult(cancellationToken);
+                project.Solution.Workspace, title, definitions).WaitAndGetResult(cancellationToken);
+        }
+
+        public static bool TryGoToDefinition(
+            ImmutableArray<DefinitionItem> definitions,
+            Project project,
+            string title,
+            IEnumerable<Lazy<IStreamingFindUsagesPresenter>> streamingPresenters,
+            CancellationToken cancellationToken)
+        {
+            if (definitions.IsDefaultOrEmpty)
+            {
+                return false;
+            }
+
+            var presenter = streamingPresenters.FirstOrDefault()?.Value;
+
+            return presenter.TryNavigateToOrPresentItemsAsync(
+                project.Solution.Workspace, title, definitions).WaitAndGetResult(cancellationToken);
         }
     }
 }
\ No newline at end of file
diff --git a/src/EditorFeatures/Core/GoToDefinition/IGoToDefinitionSymbolService.cs b/src/EditorFeatures/Core/GoToDefinition/IGoToDefinitionSymbolService.cs
new file mode 100644
index 0000000000000..99a30194235f7
--- /dev/null
+++ b/src/EditorFeatures/Core/GoToDefinition/IGoToDefinitionSymbolService.cs
@@ -0,0 +1,14 @@
+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.CodeAnalysis.Host;
+using Microsoft.CodeAnalysis.Text;
+
+namespace Microsoft.CodeAnalysis.Editor.GoToDefinition
+{
+    internal interface IGoToDefinitionSymbolService : ILanguageService
+    {
+        Task<(ISymbol, TextSpan)> GetSymbolAndBoundSpanAsync(Document document, int position, CancellationToken cancellationToken);
+    }
+}
diff --git a/src/EditorFeatures/Core/GoToDefinition/IGoToSymbolService.cs b/src/EditorFeatures/Core/GoToDefinition/IGoToSymbolService.cs
new file mode 100644
index 0000000000000..59b5e560f7102
--- /dev/null
+++ b/src/EditorFeatures/Core/GoToDefinition/IGoToSymbolService.cs
@@ -0,0 +1,18 @@
+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using System.Linq;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.CodeAnalysis.Host;
+
+namespace Microsoft.CodeAnalysis.Editor.GoToDefinition
+{
+    internal interface IGoToSymbolService : ILanguageService
+    {
+        Task GetDefinitionsAsync(GoToDefinitionContext context);
+    }
+}
diff --git a/src/EditorFeatures/Core/GoToDefinition/WellKnownDefinitionTypes.cs b/src/EditorFeatures/Core/GoToDefinition/WellKnownDefinitionTypes.cs
new file mode 100644
index 0000000000000..7de843a6cc9b8
--- /dev/null
+++ b/src/EditorFeatures/Core/GoToDefinition/WellKnownDefinitionTypes.cs
@@ -0,0 +1,10 @@
+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+
+namespace Microsoft.CodeAnalysis.Editor.GoToDefinition
+{
+    internal class WellKnownDefinitionTypes
+    {
+        public const string Definition = nameof(Definition);
+    }
+}
diff --git a/src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.NavigableSymbol.cs b/src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.NavigableSymbol.cs
new file mode 100644
index 0000000000000..94921c91aca09
--- /dev/null
+++ b/src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.NavigableSymbol.cs
@@ -0,0 +1,61 @@
+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using Microsoft.CodeAnalysis.Editor.GoToDefinition;
+using Microsoft.CodeAnalysis.Editor.Host;
+using Microsoft.CodeAnalysis.FindUsages;
+using Microsoft.VisualStudio.Language.Intellisense;
+using Microsoft.VisualStudio.Text;
+using Roslyn.Utilities;
+
+namespace Microsoft.CodeAnalysis.Editor.NavigableSymbols
+{
+    internal partial class NavigableSymbolService
+    {
+        private class NavigableSymbol : INavigableSymbol
+        {
+            private readonly ImmutableArray<DefinitionItem> _definitions;
+            private readonly SnapshotSpan _span;
+            private readonly Document _document;
+            private readonly IEnumerable<Lazy<IStreamingFindUsagesPresenter>> _presenters;
+            private readonly IWaitIndicator _waitIndicator;
+
+            public NavigableSymbol(
+                ImmutableArray<DefinitionItem> definitions,
+                SnapshotSpan span,
+                Document document,
+                IEnumerable<Lazy<IStreamingFindUsagesPresenter>> streamingPresenters,
+                IWaitIndicator waitIndicator)
+            {
+                Contract.ThrowIfFalse(definitions.Length > 0);
+
+                _definitions = definitions;
+                _span = span;
+                _document = document;
+                _presenters = streamingPresenters;
+                _waitIndicator = waitIndicator;
+            }
+
+            public SnapshotSpan SymbolSpan => _span;
+
+            public IEnumerable<INavigableRelationship> Relationships =>
+                SpecializedCollections.SingletonEnumerable(PredefinedNavigableRelationships.Definition);
+
+            public void Navigate(INavigableRelationship relationship) =>
+                _waitIndicator.Wait(
+                    title: EditorFeaturesResources.Go_to_Definition,
+                    message: EditorFeaturesResources.Navigating_to_definition,
+                    allowCancel: true,
+                    showProgress: false,
+                    action: context => GoToDefinitionHelpers.TryGoToDefinition(
+                        _definitions,
+                        _document.Project,
+                        _definitions[0].NameDisplayParts.GetFullText(),
+                        _presenters,
+                        context.CancellationToken)
+                    );
+        }
+    }
+}
diff --git a/src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.NavigableSymbolSource.cs b/src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.NavigableSymbolSource.cs
new file mode 100644
index 0000000000000..418279a87be0a
--- /dev/null
+++ b/src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.NavigableSymbolSource.cs
@@ -0,0 +1,76 @@
+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.CodeAnalysis.Editor.GoToDefinition;
+using Microsoft.CodeAnalysis.Editor.Host;
+using Microsoft.CodeAnalysis.Shared.Extensions;
+using Microsoft.CodeAnalysis.Text;
+using Microsoft.VisualStudio.Language.Intellisense;
+using Microsoft.VisualStudio.Text;
+using Microsoft.VisualStudio.Text.Editor;
+
+namespace Microsoft.CodeAnalysis.Editor.NavigableSymbols
+{
+    internal partial class NavigableSymbolService
+    {
+        private partial class NavigableSymbolSource : INavigableSymbolSource
+        {
+            private readonly IEnumerable<Lazy<IStreamingFindUsagesPresenter>> _presenters;
+            private readonly IWaitIndicator _waitIndicator;
+
+            private bool _disposed;
+
+            public NavigableSymbolSource(
+                IEnumerable<Lazy<IStreamingFindUsagesPresenter>> streamingPresenters,
+                IWaitIndicator waitIndicator)
+            {
+                _presenters = streamingPresenters;
+                _waitIndicator = waitIndicator;
+            }
+
+            public void Dispose()
+            {
+                _disposed = true;
+            }
+
+            public async Task<INavigableSymbol> GetNavigableSymbolAsync(SnapshotSpan triggerSpan, CancellationToken cancellationToken)
+            {
+                if (_disposed)
+                {
+                    return null;
+                }
+
+                var snapshot = triggerSpan.Snapshot;
+                var position = triggerSpan.Start;
+                var document = snapshot.GetOpenDocumentInCurrentContextWithChanges();
+                if (document == null)
+                {
+                    return null;
+                }
+
+                var service = document.GetLanguageService<IGoToSymbolService>();
+
+                var context = new GoToDefinitionContext(
+                    document, 
+                    position, 
+                    cancellationToken: cancellationToken);
+
+                await service.GetDefinitionsAsync(context).ConfigureAwait(false);
+
+                if (!context.Items.TryGetValue(WellKnownDefinitionTypes.Definition, out var definitions))
+                {
+                    return null;
+                }
+
+                var span = context.Span;
+                var snapshotSpan = new SnapshotSpan(snapshot, span.Start, span.Length);
+                return new NavigableSymbol(definitions.ToImmutableArray(), snapshotSpan, document, _presenters, _waitIndicator);
+            }
+        }
+    }
+}
diff --git a/src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.cs b/src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.cs
new file mode 100644
index 0000000000000..c1b6c945ea297
--- /dev/null
+++ b/src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.cs
@@ -0,0 +1,39 @@
+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition;
+using Microsoft.CodeAnalysis.Editor.Host;
+using Microsoft.CodeAnalysis.Editor.Shared.Extensions;
+using Microsoft.VisualStudio.Language.Intellisense;
+using Microsoft.VisualStudio.Text;
+using Microsoft.VisualStudio.Text.Editor;
+using Microsoft.VisualStudio.Utilities;
+
+namespace Microsoft.CodeAnalysis.Editor.NavigableSymbols
+{
+    [Export(typeof(INavigableSymbolSourceProvider))]
+    [Name(nameof(NavigableSymbolService))]
+    [ContentType(ContentTypeNames.RoslynContentType)]
+    internal partial class NavigableSymbolService : INavigableSymbolSourceProvider
+    {
+        private static readonly object s_key = new object();
+        private readonly IEnumerable<Lazy<IStreamingFindUsagesPresenter>> _streamingPresenters;
+        private readonly IWaitIndicator _waitIndicator;
+
+        [ImportingConstructor]
+        public NavigableSymbolService(
+            IWaitIndicator waitIndicator,
+            [ImportMany] IEnumerable<Lazy<IStreamingFindUsagesPresenter>> streamingPresenters)
+        {
+            _waitIndicator = waitIndicator;
+            _streamingPresenters = streamingPresenters;
+        }
+
+        public INavigableSymbolSource TryCreateNavigableSymbolSource(ITextView textView, ITextBuffer buffer)
+        {
+            return textView.GetOrCreatePerSubjectBufferProperty(buffer, s_key,
+                (v, b) => new NavigableSymbolSource(_streamingPresenters, _waitIndicator));
+        }
+    }
+}
diff --git a/src/EditorFeatures/Test/CommentSelection/CommentUncommentSelectionCommandHandlerTests.cs b/src/EditorFeatures/Test/CommentSelection/CommentUncommentSelectionCommandHandlerTests.cs
index c0d9e5b4ef048..34a2d8aa63f72 100644
--- a/src/EditorFeatures/Test/CommentSelection/CommentUncommentSelectionCommandHandlerTests.cs
+++ b/src/EditorFeatures/Test/CommentSelection/CommentUncommentSelectionCommandHandlerTests.cs
@@ -562,7 +562,7 @@ private static void CommentSelection(ITextView textView, IEnumerable<TextChange>
             commandHandler.CollectEdits(service,
                 textView.Selection.GetSnapshotSpansOnBuffer(textView.TextBuffer), textChanges, trackingSpans, operation);
 
-            AssertEx.SetEqual(expectedChanges, textChanges);
+            Roslyn.Test.Utilities.AssertEx.SetEqual(expectedChanges, textChanges);
 
             // Actually apply the edit to let the tracking spans adjust.
             using (var edit = textView.TextBuffer.CreateEdit())
@@ -579,7 +579,7 @@ private static void CommentSelection(ITextView textView, IEnumerable<TextChange>
 
             if (expectedSelectedSpans != null)
             {
-                AssertEx.Equal(expectedSelectedSpans, textView.Selection.SelectedSpans.Select(snapshotSpan => snapshotSpan.Span));
+                Roslyn.Test.Utilities.AssertEx.Equal(expectedSelectedSpans, textView.Selection.SelectedSpans.Select(snapshotSpan => snapshotSpan.Span));
             }
         }
 
diff --git a/src/EditorFeatures/Test/Utilities/PatternMatcherTests.cs b/src/EditorFeatures/Test/Utilities/PatternMatcherTests.cs
index 90d1201e9bb4d..363f23f778bde 100644
--- a/src/EditorFeatures/Test/Utilities/PatternMatcherTests.cs
+++ b/src/EditorFeatures/Test/Utilities/PatternMatcherTests.cs
@@ -159,12 +159,12 @@ public void BreakIntoWordParts_TwoUppercaseCharacters()
 
         private void VerifyBreakIntoWordParts(string original, params string[] parts)
         {
-            AssertEx.Equal(parts, BreakIntoWordParts(original));
+            Roslyn.Test.Utilities.AssertEx.Equal(parts, BreakIntoWordParts(original));
         }
 
         private void VerifyBreakIntoCharacterParts(string original, params string[] parts)
         {
-            AssertEx.Equal(parts, BreakIntoCharacterParts(original));
+            Roslyn.Test.Utilities.AssertEx.Equal(parts, BreakIntoCharacterParts(original));
         }
 
         private const bool CaseSensitive = true;
diff --git a/src/EditorFeatures/Test2/NavigableSymbols/NavigableSymbolsTest.vb b/src/EditorFeatures/Test2/NavigableSymbols/NavigableSymbolsTest.vb
new file mode 100644
index 0000000000000..5c3d2ecaee323
--- /dev/null
+++ b/src/EditorFeatures/Test2/NavigableSymbols/NavigableSymbolsTest.vb
@@ -0,0 +1,73 @@
+' Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+Imports System
+Imports System.Linq
+Imports System.Threading
+Imports System.Threading.Tasks
+Imports Microsoft.CodeAnalysis.Editor.Host
+Imports Microsoft.CodeAnalysis.Editor.NavigableSymbols
+Imports Microsoft.CodeAnalysis.Editor.UnitTests.BraceMatching
+Imports Microsoft.CodeAnalysis.Editor.UnitTests.Utilities
+Imports Microsoft.CodeAnalysis.Editor.UnitTests.Utilities.GoToHelpers
+Imports Microsoft.CodeAnalysis.Editor.UnitTests.Workspaces
+Imports Microsoft.CodeAnalysis.Navigation
+Imports Microsoft.VisualStudio.Composition
+Imports Microsoft.VisualStudio.Text
+Imports Roslyn.Test.Utilities
+Imports Xunit
+
+Namespace Microsoft.CodeAnalysis.Editor.UnitTests.NavigableSymbols
+
+    Public Class NavigableSymbolsTest
+
+        Private Shared ReadOnly s_exportProvider As ExportProvider = MinimalTestExportProvider.CreateExportProvider(
+            TestExportProvider.EntireAssemblyCatalogWithCSharpAndVisualBasic.WithParts(
+                GetType(MockDocumentNavigationServiceProvider),
+                GetType(MockSymbolNavigationServiceProvider)))
+
+        <WpfFact>
+        Public Async Function TestCharp() As Task
+            Using workspace = TestWorkspace.CreateCSharp("
+class C
+{
+    C$$ c
+}", exportProvider:=s_exportProvider)
+
+
+                Await TestNavigated(workspace)
+            End Using
+        End Function
+
+        <WpfFact>
+        Public Async Function TestVB() As Task
+            Using workspace = TestWorkspace.CreateVisualBasic("
+Class C
+    Dim c as C$$
+End Class", exportProvider:=s_exportProvider)
+
+
+                Await TestNavigated(workspace)
+            End Using
+        End Function
+
+        Private Async Function TestNavigated(workspace As TestWorkspace) As Task
+
+            Dim presenter = {New Lazy(Of IStreamingFindUsagesPresenter)(Function() New MockStreamingFindUsagesPresenter(Sub() Return))}
+            Dim service = New NavigableSymbolService(TestWaitIndicator.Default, presenter)
+            Dim view = workspace.Documents.First().GetTextView()
+            Dim Buffer = workspace.Documents.First().GetTextBuffer()
+            Dim caretPosition = view.Caret.Position.BufferPosition.Position
+            Dim Span = New SnapshotSpan(Buffer.CurrentSnapshot, New Span(caretPosition, 0))
+            Dim source = service.TryCreateNavigableSymbolSource(view, Buffer)
+            Dim symbol = Await source.GetNavigableSymbolAsync(Span, CancellationToken.None)
+
+            Assert.NotNull(symbol)
+            symbol.Navigate(symbol.Relationships.First())
+
+            Dim navigationService = DirectCast(workspace.Services.GetService(Of IDocumentNavigationService)(), MockDocumentNavigationServiceProvider.MockDocumentNavigationService)
+            Assert.Equal(True, navigationService.TryNavigateToLineAndOffsetReturnValue)
+            Assert.Equal(True, navigationService.TryNavigateToPositionReturnValue)
+            Assert.Equal(True, navigationService.TryNavigateToSpanReturnValue)
+        End Function
+    End Class
+End Namespace
diff --git a/src/EditorFeatures/TestUtilities/TextEditorFactoryExtensions.cs b/src/EditorFeatures/TestUtilities/TextEditorFactoryExtensions.cs
index 0332c0c778e8f..228928231472a 100644
--- a/src/EditorFeatures/TestUtilities/TextEditorFactoryExtensions.cs
+++ b/src/EditorFeatures/TestUtilities/TextEditorFactoryExtensions.cs
@@ -15,7 +15,17 @@ public static DisposableTextView CreateDisposableTextView(this ITextEditorFactor
 
         public static DisposableTextView CreateDisposableTextView(this ITextEditorFactoryService textEditorFactory, ITextBuffer buffer)
         {
-            return new DisposableTextView(textEditorFactory.CreateTextView(buffer));
+            // Every default role but outlining. Starting in 15.2, the editor
+            // OutliningManager imports JoinableTaskContext in a way that's 
+            // difficult to satisfy in our unit tests. Since we don't directly
+            // depend on it, just disable it
+            var roles = textEditorFactory.CreateTextViewRoleSet(PredefinedTextViewRoles.Analyzable,
+                PredefinedTextViewRoles.Document,
+                PredefinedTextViewRoles.Editable,
+                PredefinedTextViewRoles.Interactive,
+                PredefinedTextViewRoles.Zoomable);
+
+            return new DisposableTextView(textEditorFactory.CreateTextView(buffer, roles));
         }
     }
 
diff --git a/src/EditorFeatures/TestUtilities/Workspaces/TestHostDocument.cs b/src/EditorFeatures/TestUtilities/Workspaces/TestHostDocument.cs
index ff7fc26918752..7606af0ebed6a 100644
--- a/src/EditorFeatures/TestUtilities/Workspaces/TestHostDocument.cs
+++ b/src/EditorFeatures/TestUtilities/Workspaces/TestHostDocument.cs
@@ -135,8 +135,8 @@ public bool IsGenerated
         }
 
         public TestHostDocument(
-            string text = "", string displayName = "", 
-            SourceCodeKind sourceCodeKind = SourceCodeKind.Regular, 
+            string text = "", string displayName = "",
+            SourceCodeKind sourceCodeKind = SourceCodeKind.Regular,
             DocumentId id = null, string filePath = null,
             IReadOnlyList<string> folders = null)
         {
@@ -194,7 +194,7 @@ public override Task<TextAndVersion> LoadTextAndVersionAsync(Workspace workspace
                 return Task.FromResult(TextAndVersion.Create(text, VersionStamp.Create(), _hostDocument.FilePath));
             }
         }
-        
+
         public IWpfTextView GetTextView()
         {
             if (_textView == null)
@@ -203,7 +203,18 @@ public IWpfTextView GetTextView()
 
                 WpfTestCase.RequireWpfFact($"Creates an IWpfTextView through {nameof(TestHostDocument)}.{nameof(GetTextView)}");
 
-                _textView = _exportProvider.GetExportedValue<ITextEditorFactoryService>().CreateTextView(this.TextBuffer);
+                var factory = _exportProvider.GetExportedValue<ITextEditorFactoryService>();
+
+                // Every default role but outlining. Starting in 15.2, the editor
+                // OutliningManager imports JoinableTaskContext in a way that's 
+                // difficult to satisfy in our unit tests. Since we don't directly
+                // depend on it, just disable it
+                var roles = factory.CreateTextViewRoleSet(PredefinedTextViewRoles.Analyzable,
+                    PredefinedTextViewRoles.Document,
+                    PredefinedTextViewRoles.Editable,
+                    PredefinedTextViewRoles.Interactive,
+                    PredefinedTextViewRoles.Zoomable);
+                _textView = factory.CreateTextView(this.TextBuffer, roles);
                 if (this.CursorPosition.HasValue)
                 {
                     _textView.Caret.MoveTo(new SnapshotPoint(_textView.TextSnapshot, CursorPosition.Value));
diff --git a/src/EditorFeatures/TestUtilities2/ServicesTestUtilities2.vbproj b/src/EditorFeatures/TestUtilities2/ServicesTestUtilities2.vbproj
index 8be12b57b5585..96ff80e86d2b7 100644
--- a/src/EditorFeatures/TestUtilities2/ServicesTestUtilities2.vbproj
+++ b/src/EditorFeatures/TestUtilities2/ServicesTestUtilities2.vbproj
@@ -151,6 +151,7 @@
   <ItemGroup>
     <InternalsVisibleToTest Include="Roslyn.VisualStudio.Services.UnitTests" />
     <InternalsVisibleToTest Include="Roslyn.Services.Editor2.UnitTests" />
+    <InternalsVisibleToTest Include="Roslyn.Services.Editor.UnitTests" />
   </ItemGroup>
   <ItemGroup>
     <Import Include="Microsoft.CodeAnalysis.Editor" />
diff --git a/src/EditorFeatures/TestUtilities2/Utilities/GoToHelpers/GoToTestHelpers.vb b/src/EditorFeatures/TestUtilities2/Utilities/GoToHelpers/GoToTestHelpers.vb
index c7c42d392eab7..3f29c283b4a99 100644
--- a/src/EditorFeatures/TestUtilities2/Utilities/GoToHelpers/GoToTestHelpers.vb
+++ b/src/EditorFeatures/TestUtilities2/Utilities/GoToHelpers/GoToTestHelpers.vb
@@ -1,5 +1,7 @@
 ' Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
+Imports Microsoft.CodeAnalysis.Editor.CSharp.GoToDefinition
+Imports Microsoft.CodeAnalysis.Editor.VisualBasic.GoToDefinition
 Imports Microsoft.CodeAnalysis.Editor.Host
 Imports Microsoft.CodeAnalysis.Editor.UnitTests.Workspaces
 Imports Microsoft.CodeAnalysis.GeneratedCodeRecognition
@@ -13,7 +15,9 @@ Namespace Microsoft.CodeAnalysis.Editor.UnitTests.Utilities.GoToHelpers
         Public ReadOnly Catalog As ComposableCatalog = TestExportProvider.MinimumCatalogWithCSharpAndVisualBasic.WithParts(
                         GetType(MockDocumentNavigationServiceFactory),
                         GetType(DefaultSymbolNavigationServiceFactory),
-                        GetType(GeneratedCodeRecognitionService))
+                        GetType(GeneratedCodeRecognitionService),
+                        GetType(CSharpGoToDefinitionSymbolService),
+                        GetType(VisualBasicGoToDefinitionSymbolService))
 
         Public ReadOnly ExportProvider As ExportProvider = MinimalTestExportProvider.CreateExportProvider(Catalog)
 
diff --git a/src/EditorFeatures/VisualBasic/BasicEditorFeatures.vbproj b/src/EditorFeatures/VisualBasic/BasicEditorFeatures.vbproj
index 79ee5ff8d6c4c..9f4e8c1ec3290 100644
--- a/src/EditorFeatures/VisualBasic/BasicEditorFeatures.vbproj
+++ b/src/EditorFeatures/VisualBasic/BasicEditorFeatures.vbproj
@@ -97,7 +97,9 @@
     <Compile Include="Formatting\Indentation\SpecialFormattingOperation.vb" />
     <Compile Include="Formatting\Indentation\VisualBasicIndentationService.Indenter.vb" />
     <Compile Include="Formatting\Indentation\VisualBasicIndentationService.vb" />
+    <Compile Include="GoToDefinition\VisualBasicGoToDefinitionItemService.vb" />
     <Compile Include="GoToDefinition\VisualBasicGoToDefinitionService.vb" />
+    <Compile Include="GoToDefinition\VisualBasicGoToDefinitionSymbolService.vb" />
     <Compile Include="Highlighting\KeywordHighlighters\AccessorDeclarationHighlighter.vb" />
     <Compile Include="Highlighting\KeywordHighlighters\ConditionalPreprocessorHighlighter.vb" />
     <Compile Include="Highlighting\KeywordHighlighters\ConstructorDeclarationHighlighter.vb" />
diff --git a/src/EditorFeatures/VisualBasic/GoToDefinition/VisualBasicGoToDefinitionItemService.vb b/src/EditorFeatures/VisualBasic/GoToDefinition/VisualBasicGoToDefinitionItemService.vb
new file mode 100644
index 0000000000000..df953bf33714d
--- /dev/null
+++ b/src/EditorFeatures/VisualBasic/GoToDefinition/VisualBasicGoToDefinitionItemService.vb
@@ -0,0 +1,11 @@
+Imports System.Composition
+Imports Microsoft.CodeAnalysis.Editor.GoToDefinition
+Imports Microsoft.CodeAnalysis.Host.Mef
+
+Namespace Microsoft.CodeAnalysis.Editor.VisualBasic.GoToDefinition
+    <ExportLanguageService(GetType(IGoToSymbolService), LanguageNames.VisualBasic), [Shared]>
+    Friend Class VisualBasicGoToDefinitionItemService
+        Inherits AbstractGoToDefinitionItemService
+
+    End Class
+End Namespace
diff --git a/src/EditorFeatures/VisualBasic/GoToDefinition/VisualBasicGoToDefinitionService.vb b/src/EditorFeatures/VisualBasic/GoToDefinition/VisualBasicGoToDefinitionService.vb
index b4298240d4279..be3905bc47d65 100644
--- a/src/EditorFeatures/VisualBasic/GoToDefinition/VisualBasicGoToDefinitionService.vb
+++ b/src/EditorFeatures/VisualBasic/GoToDefinition/VisualBasicGoToDefinitionService.vb
@@ -15,9 +15,5 @@ Namespace Microsoft.CodeAnalysis.Editor.VisualBasic.GoToDefinition
         Public Sub New(<ImportMany> streamingPresenters As IEnumerable(Of Lazy(Of IStreamingFindUsagesPresenter)))
             MyBase.New(streamingPresenters)
         End Sub
-
-        Protected Overrides Function FindRelatedExplicitlyDeclaredSymbol(symbol As ISymbol, compilation As Compilation) As ISymbol
-            Return symbol.FindRelatedExplicitlyDeclaredSymbol(compilation)
-        End Function
     End Class
 End Namespace
\ No newline at end of file
diff --git a/src/EditorFeatures/VisualBasic/GoToDefinition/VisualBasicGoToDefinitionSymbolService.vb b/src/EditorFeatures/VisualBasic/GoToDefinition/VisualBasicGoToDefinitionSymbolService.vb
new file mode 100644
index 0000000000000..228b4a7d70945
--- /dev/null
+++ b/src/EditorFeatures/VisualBasic/GoToDefinition/VisualBasicGoToDefinitionSymbolService.vb
@@ -0,0 +1,18 @@
+' Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+Imports System.Composition
+Imports Microsoft.CodeAnalysis.Editor.GoToDefinition
+Imports Microsoft.CodeAnalysis.Editor.Host
+Imports Microsoft.CodeAnalysis.Host.Mef
+Imports Microsoft.CodeAnalysis.VisualBasic.Utilities
+
+Namespace Microsoft.CodeAnalysis.Editor.VisualBasic.GoToDefinition
+    <ExportLanguageService(GetType(IGoToDefinitionSymbolService), LanguageNames.VisualBasic), [Shared]>
+    Friend Class VisualBasicGoToDefinitionSymbolService
+        Inherits AbstractGoToDefinitionSymbolService
+
+        Protected Overrides Function FindRelatedExplicitlyDeclaredSymbol(symbol As ISymbol, compilation As Compilation) As ISymbol
+            Return symbol.FindRelatedExplicitlyDeclaredSymbol(compilation)
+        End Function
+    End Class
+End Namespace
\ No newline at end of file
diff --git a/src/VisualStudio/Core/Def/ServicesVisualStudio.csproj b/src/VisualStudio/Core/Def/ServicesVisualStudio.csproj
index f3d937caeaeba..fe82739d4b538 100644
--- a/src/VisualStudio/Core/Def/ServicesVisualStudio.csproj
+++ b/src/VisualStudio/Core/Def/ServicesVisualStudio.csproj
@@ -448,6 +448,9 @@
     <PackageReference Include="Newtonsoft.Json">
       <Version>$(NewtonsoftJsonVersion)</Version>
     </PackageReference>
+	<PackageReference Include="Microsoft.VisualStudio.Shell.Interop.15.3.DesignTime">
+		<Version>$(MicrosoftVisualStudioShellInterop153DesignTimeVersion)</Version>
+	</PackageReference>
   </ItemGroup>
   <ItemGroup>
     <Compile Include="CodeMarkers\ManagedCodeMarkers.cs" />
diff --git a/src/VisualStudio/Core/Next/ServicesVisualStudio.Next.csproj b/src/VisualStudio/Core/Next/ServicesVisualStudio.Next.csproj
index 226aa9490b044..425d0f835e7d1 100644
--- a/src/VisualStudio/Core/Next/ServicesVisualStudio.Next.csproj
+++ b/src/VisualStudio/Core/Next/ServicesVisualStudio.Next.csproj
@@ -126,6 +126,12 @@
     <PackageReference Include="Microsoft.VisualStudio.Diagnostics.PerformanceProvider">
       <Version>$(MicrosoftVisualStudioDiagnosticsPerformanceProviderVersion)</Version>
     </PackageReference>
+    <PackageReference Include="Microsoft.VisualStudio.Shell.Interop.15.3.DesignTime">
+      <Version>$(MicrosoftVisualStudioShellInterop153DesignTimeVersion)</Version>
+    </PackageReference>
+    <PackageReference Include="StreamJsonRPC">
+      <Version>$(StreamJsonRPCVersion)</Version>
+    </PackageReference>
   </ItemGroup>
   <ItemGroup>
     <PublicAPI Include="PublicAPI.Shipped.txt" />
diff --git a/src/Workspaces/Core/Portable/Shared/Extensions/SemanticModelExtensions.cs b/src/Workspaces/Core/Portable/Shared/Extensions/SemanticModelExtensions.cs
index de8e9c1668e98..f774fa052ec65 100644
--- a/src/Workspaces/Core/Portable/Shared/Extensions/SemanticModelExtensions.cs
+++ b/src/Workspaces/Core/Portable/Shared/Extensions/SemanticModelExtensions.cs
@@ -6,6 +6,7 @@
 using System.Threading;
 using Microsoft.CodeAnalysis.LanguageServices;
 using Microsoft.CodeAnalysis.Shared.Utilities;
+using Microsoft.CodeAnalysis.Text;
 using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.Shared.Extensions
@@ -13,23 +14,26 @@ namespace Microsoft.CodeAnalysis.Shared.Extensions
     internal struct TokenSemanticInfo
     {
         public static readonly TokenSemanticInfo Empty = new TokenSemanticInfo(
-            null, null, ImmutableArray<ISymbol>.Empty, null);
+            null, null, ImmutableArray<ISymbol>.Empty, null, default(TextSpan));
 
         public readonly ISymbol DeclaredSymbol;
         public readonly IAliasSymbol AliasSymbol;
         public readonly ImmutableArray<ISymbol> ReferencedSymbols;
         public readonly ITypeSymbol Type;
+        public readonly TextSpan Span;
 
         public TokenSemanticInfo(
             ISymbol declaredSymbol, 
             IAliasSymbol aliasSymbol,
             ImmutableArray<ISymbol> referencedSymbols,
-            ITypeSymbol type)
+            ITypeSymbol type,
+            TextSpan span)
         {
             DeclaredSymbol = declaredSymbol;
             AliasSymbol = aliasSymbol;
             ReferencedSymbols = referencedSymbols;
             Type = type;
+            Span = span;
         }
 
         public ImmutableArray<ISymbol> GetSymbols(bool includeType)
@@ -206,7 +210,7 @@ private static ISymbol MapSymbol(ISymbol symbol, ITypeSymbol type)
                 }
             }
 
-            return new TokenSemanticInfo(declaredSymbol, aliasSymbol, allSymbols, type);
+            return new TokenSemanticInfo(declaredSymbol, aliasSymbol, allSymbols, type, token.Span);
         }
 
         public static SemanticModel GetOriginalSemanticModel(this SemanticModel semanticModel)

From 62ea514285fbd2cc185b7e007c33855e6d26d15b Mon Sep 17 00:00:00 2001
From: Ravi Chande <rchande@microsoft.com>
Date: Tue, 20 Jun 2017 12:50:36 -0700
Subject: [PATCH 06/77] Implement ISuggestedActionsSource2

---
 build/Defaults/Net460/app.config              |   2 +-
 build/Defaults/Net462/app.config              |   2 +-
 build/Defaults/Portable/app.config            |   2 +-
 build/Targets/Packages.props                  |  71 +++---
 .../Extension/CompilerExtension.csproj        |   5 +-
 .../CodeFixes/CodeFixService.cs               |  89 ++++---
 .../CodeFixes/ICodeFixService.cs              |   3 +-
 .../Suggestions/SuggestedActionsSource.cs     | 217 +++++++++++-------
 .../SuggestedActionsSourceProvider.cs         |   5 +-
 .../Test/CodeFixes/CodeFixServiceTests.cs     |   4 +-
 .../TextEditorFactoryExtensions.cs            |  12 +-
 .../Workspaces/TestHostDocument.cs            |  13 +-
 src/Tools/GenerateSdkPackages/files.txt       |   1 +
 .../Core/Def/ServicesVisualStudio.csproj      |   3 +
 .../Next/ServicesVisualStudio.Next.csproj     |   9 +
 15 files changed, 283 insertions(+), 155 deletions(-)

diff --git a/build/Defaults/Net460/app.config b/build/Defaults/Net460/app.config
index 8db45c0c5c11b..5194a2fa0a970 100644
--- a/build/Defaults/Net460/app.config
+++ b/build/Defaults/Net460/app.config
@@ -75,7 +75,7 @@
       </dependentAssembly>
       <dependentAssembly>
         <assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" culture="neutral"/>
-        <bindingRedirect oldVersion="0.0.0.0-8.0.0.0" newVersion="8.0.0.0"/>
+        <bindingRedirect oldVersion="0.0.0.0-9.0.0.0" newVersion="9.0.0.0"/>
       </dependentAssembly>
 
       <!-- Even though all of our references are to Dev15 binaries we are still pulling in BasicUndo
diff --git a/build/Defaults/Net462/app.config b/build/Defaults/Net462/app.config
index 65a0c73b38b43..7f9cf2c4f51d1 100644
--- a/build/Defaults/Net462/app.config
+++ b/build/Defaults/Net462/app.config
@@ -83,7 +83,7 @@
       </dependentAssembly>
       <dependentAssembly>
         <assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" culture="neutral"/>
-        <bindingRedirect oldVersion="0.0.0.0-8.0.0.0" newVersion="8.0.0.0"/>
+        <bindingRedirect oldVersion="0.0.0.0-9.0.0.0" newVersion="9.0.0.0"/>
       </dependentAssembly>
 
       <!-- Even though all of our references are to Dev15 binaries we are still pulling in BasicUndo
diff --git a/build/Defaults/Portable/app.config b/build/Defaults/Portable/app.config
index bbf37ae184987..56fd8dbe9a61d 100644
--- a/build/Defaults/Portable/app.config
+++ b/build/Defaults/Portable/app.config
@@ -75,7 +75,7 @@
       </dependentAssembly>
       <dependentAssembly>
         <assemblyIdentity name="Newtonsoft.Json" publicKeyToken="30ad4fe6b2a6aeed" culture="neutral"/>
-        <bindingRedirect oldVersion="0.0.0.0-8.0.0.0" newVersion="8.0.0.0"/>
+        <bindingRedirect oldVersion="0.0.0.0-9.0.0.0" newVersion="9.0.0.0"/>
       </dependentAssembly>
 	  <dependentAssembly>
         <assemblyIdentity name="Microsoft.VisualStudio.Validation" publicKeyToken="b03f5f7f11d50a3a" culture="neutral"/>
diff --git a/build/Targets/Packages.props b/build/Targets/Packages.props
index 6833448bd7223..72392757d95ff 100644
--- a/build/Targets/Packages.props
+++ b/build/Targets/Packages.props
@@ -41,7 +41,7 @@
     <MicrosoftDiaSymReaderPortablePdbVersion>1.3.0</MicrosoftDiaSymReaderPortablePdbVersion>
     <MicrosoftDotNetIBCMerge>4.7.2-alpha-00001</MicrosoftDotNetIBCMerge>
     <MicrosoftIdentityModelClientsActiveDirectoryVersion>3.13.8</MicrosoftIdentityModelClientsActiveDirectoryVersion>
-    <MicrosoftInternalPerformanceCodeMarkersDesignTimeVersion>15.0.26507-alpha</MicrosoftInternalPerformanceCodeMarkersDesignTimeVersion>
+    <MicrosoftInternalPerformanceCodeMarkersDesignTimeVersion>15.0.26606-alpha</MicrosoftInternalPerformanceCodeMarkersDesignTimeVersion>
     <MicrosoftInternalVisualStudioShellInterop140DesignTimeVersion>14.3.25407-alpha</MicrosoftInternalVisualStudioShellInterop140DesignTimeVersion>
     <MicrosoftMetadataVisualizerVersion>1.0.0-beta1-61531-03</MicrosoftMetadataVisualizerVersion>
     <MicrosoftMSXMLVersion>8.0.0.0-alpha</MicrosoftMSXMLVersion>
@@ -60,35 +60,35 @@
     <MicrosoftNetSdkVersion>2.0.0-alpha-20170405-2</MicrosoftNetSdkVersion>
     <MicrosoftNuGetBuildTasksVersion>0.1.0</MicrosoftNuGetBuildTasksVersion>
     <MicrosoftPortableTargetsVersion>0.1.2-dev</MicrosoftPortableTargetsVersion>
-    <MicrosoftServiceHubClientVersion>1.1.18-rc-g92b2150dd1</MicrosoftServiceHubClientVersion>
+    <MicrosoftServiceHubClientVersion>1.1.31-rc</MicrosoftServiceHubClientVersion>
     <MicrosoftTplDataflowVersion>4.5.24</MicrosoftTplDataflowVersion>
     <MicrosoftVisualBasicVersion>10.1.0</MicrosoftVisualBasicVersion>
-    <MicrosoftVisualStudioCallHierarchyPackageDefinitionsVersion>15.0.26507-alpha</MicrosoftVisualStudioCallHierarchyPackageDefinitionsVersion>
-    <MicrosoftVisualStudioCodeAnalysisSdkUIVersion>15.0.26507-alpha</MicrosoftVisualStudioCodeAnalysisSdkUIVersion>
-    <MicrosoftVisualStudioComponentModelHostVersion>15.0.26507-alpha</MicrosoftVisualStudioComponentModelHostVersion>
+    <MicrosoftVisualStudioCallHierarchyPackageDefinitionsVersion>15.0.26606-alpha</MicrosoftVisualStudioCallHierarchyPackageDefinitionsVersion>
+    <MicrosoftVisualStudioCodeAnalysisSdkUIVersion>15.0.26606-alpha</MicrosoftVisualStudioCodeAnalysisSdkUIVersion>
+    <MicrosoftVisualStudioComponentModelHostVersion>15.0.26606-alpha</MicrosoftVisualStudioComponentModelHostVersion>
     <MicrosoftVisualStudioCompositionVersion>15.0.66-rc</MicrosoftVisualStudioCompositionVersion>
-    <MicrosoftVisualStudioCoreUtilityVersion>15.0.26507-alpha</MicrosoftVisualStudioCoreUtilityVersion>
+    <MicrosoftVisualStudioCoreUtilityVersion>15.0.26606-alpha</MicrosoftVisualStudioCoreUtilityVersion>
     <MicrosoftVisualStudioDebuggerEngineVersion>15.0.26201-gamma</MicrosoftVisualStudioDebuggerEngineVersion>
     <MicrosoftVisualStudioDebuggerMetadataVersion>15.0.26201-gamma</MicrosoftVisualStudioDebuggerMetadataVersion>
     <MicrosoftVisualStudioDebuggerInterop100Version>10.0.30319</MicrosoftVisualStudioDebuggerInterop100Version>
     <MicrosoftVisualStudioDesignerInterfacesVersion>1.1.4322</MicrosoftVisualStudioDesignerInterfacesVersion>
-    <MicrosoftVisualStudioDiagnosticsPerformanceProviderVersion>15.0.26507-alpha</MicrosoftVisualStudioDiagnosticsPerformanceProviderVersion>
-    <MicrosoftVisualStudioEditorVersion>15.0.26507-alpha</MicrosoftVisualStudioEditorVersion>
-    <MicrosoftVisualStudioGraphModelVersion>15.0.26507-alpha</MicrosoftVisualStudioGraphModelVersion>
-    <MicrosoftVisualStudioImageCatalogVersion>15.0.26507-alpha</MicrosoftVisualStudioImageCatalogVersion>
-    <MicrosoftVisualStudioImagingVersion>15.0.26507-alpha</MicrosoftVisualStudioImagingVersion>
+    <MicrosoftVisualStudioDiagnosticsPerformanceProviderVersion>15.0.26606-alpha</MicrosoftVisualStudioDiagnosticsPerformanceProviderVersion>
+    <MicrosoftVisualStudioEditorVersion>15.0.26606-alpha</MicrosoftVisualStudioEditorVersion>
+    <MicrosoftVisualStudioGraphModelVersion>15.0.26606-alpha</MicrosoftVisualStudioGraphModelVersion>
+    <MicrosoftVisualStudioImageCatalogVersion>15.0.26606-alpha</MicrosoftVisualStudioImageCatalogVersion>
+    <MicrosoftVisualStudioImagingVersion>15.0.26606-alpha</MicrosoftVisualStudioImagingVersion>
     <MicrosoftVisualStudioImagingInterop140DesignTimeVersion>14.3.25407</MicrosoftVisualStudioImagingInterop140DesignTimeVersion>
     <MicrosoftVisualStudioInteractiveWindowVersion>2.0.0-rc3-61304-01</MicrosoftVisualStudioInteractiveWindowVersion>
-    <MicrosoftVisualStudioLanguageCallHierarchyVersion>15.0.26507-alpha</MicrosoftVisualStudioLanguageCallHierarchyVersion>
-    <MicrosoftVisualStudioLanguageIntellisenseVersion>15.0.26507-alpha</MicrosoftVisualStudioLanguageIntellisenseVersion>
-    <MicrosoftVisualStudioLanguageNavigateToInterfacesVersion>15.0.26507-alpha</MicrosoftVisualStudioLanguageNavigateToInterfacesVersion>
-    <MicrosoftVisualStudioLanguageStandardClassificationVersion>15.0.26507-alpha</MicrosoftVisualStudioLanguageStandardClassificationVersion>
+    <MicrosoftVisualStudioLanguageCallHierarchyVersion>15.0.26606-alpha</MicrosoftVisualStudioLanguageCallHierarchyVersion>
+    <MicrosoftVisualStudioLanguageIntellisenseVersion>15.0.26606-alpha</MicrosoftVisualStudioLanguageIntellisenseVersion>
+    <MicrosoftVisualStudioLanguageNavigateToInterfacesVersion>15.0.26606-alpha</MicrosoftVisualStudioLanguageNavigateToInterfacesVersion>
+    <MicrosoftVisualStudioLanguageStandardClassificationVersion>15.0.26606-alpha</MicrosoftVisualStudioLanguageStandardClassificationVersion>
     <MicrosoftVisualStudioOLEInteropVersion>7.10.6070</MicrosoftVisualStudioOLEInteropVersion>
-    <MicrosoftVisualStudioPlatformVSEditorVersion>15.0.26507-alpha</MicrosoftVisualStudioPlatformVSEditorVersion>
-    <MicrosoftVisualStudioPlatformVSEditorInteropVersion>15.0.26507-alpha</MicrosoftVisualStudioPlatformVSEditorInteropVersion>
-    <MicrosoftVisualStudioProgressionCodeSchemaVersion>15.0.26507-alpha</MicrosoftVisualStudioProgressionCodeSchemaVersion>
-    <MicrosoftVisualStudioProgressionCommonVersion>15.0.26507-alpha</MicrosoftVisualStudioProgressionCommonVersion>
-    <MicrosoftVisualStudioProgressionInterfacesVersion>15.0.26507-alpha</MicrosoftVisualStudioProgressionInterfacesVersion>
+    <MicrosoftVisualStudioPlatformVSEditorVersion>15.0.26606-alpha</MicrosoftVisualStudioPlatformVSEditorVersion>
+    <MicrosoftVisualStudioPlatformVSEditorInteropVersion>15.0.26606-alpha</MicrosoftVisualStudioPlatformVSEditorInteropVersion>
+    <MicrosoftVisualStudioProgressionCodeSchemaVersion>15.0.26606-alpha</MicrosoftVisualStudioProgressionCodeSchemaVersion>
+    <MicrosoftVisualStudioProgressionCommonVersion>15.0.26606-alpha</MicrosoftVisualStudioProgressionCommonVersion>
+    <MicrosoftVisualStudioProgressionInterfacesVersion>15.0.26606-alpha</MicrosoftVisualStudioProgressionInterfacesVersion>
     <MicrosoftVisualStudioProjectSystemVersion>15.3.178-pre-g209fb07c2e</MicrosoftVisualStudioProjectSystemVersion>
     <MicrosoftVisualStudioQualityToolsUnitTestFrameworkVersion>10.0.0.0-alpha</MicrosoftVisualStudioQualityToolsUnitTestFrameworkVersion>
     <MicrosoftVisualStudioRemoteControlVersion>14.0.249-master2E2DC10C</MicrosoftVisualStudioRemoteControlVersion>
@@ -96,32 +96,33 @@
     <MicrosoftVisualStudioSetupConfigurationNativex86Version>1.3.269-rc</MicrosoftVisualStudioSetupConfigurationNativex86Version>
     <MicrosoftVisualStudioSettings140Version>14.3.25407</MicrosoftVisualStudioSettings140Version>
     <MicrosoftVisualStudioShell140Version>14.3.25407</MicrosoftVisualStudioShell140Version>
-    <MicrosoftVisualStudioShell150Version>15.0.26507-alpha</MicrosoftVisualStudioShell150Version>
-    <MicrosoftVisualStudioShellDesignVersion>15.0.26507-alpha</MicrosoftVisualStudioShellDesignVersion>
-    <MicrosoftVisualStudioShellFrameworkVersion>15.0.26507-alpha</MicrosoftVisualStudioShellFrameworkVersion>
-    <MicrosoftVisualStudioShellImmutable100Version>15.0.26507-alpha</MicrosoftVisualStudioShellImmutable100Version>
+    <MicrosoftVisualStudioShell150Version>15.0.26606-alpha</MicrosoftVisualStudioShell150Version>
+    <MicrosoftVisualStudioShellDesignVersion>15.0.26606-alpha</MicrosoftVisualStudioShellDesignVersion>
+	<MicrosoftVisualStudioShellInterop153DesignTimeVersion>15.0.26606-alpha</MicrosoftVisualStudioShellInterop153DesignTimeVersion>
+    <MicrosoftVisualStudioShellFrameworkVersion>15.0.26606-alpha</MicrosoftVisualStudioShellFrameworkVersion>
+    <MicrosoftVisualStudioShellImmutable100Version>15.0.26606-alpha</MicrosoftVisualStudioShellImmutable100Version>
     <MicrosoftVisualStudioShellImmutable110Version>15.0.25413-Preview5</MicrosoftVisualStudioShellImmutable110Version>
     <MicrosoftVisualStudioShellInteropVersion>7.10.6071</MicrosoftVisualStudioShellInteropVersion>
     <MicrosoftVisualStudioShellInterop100Version>10.0.30319</MicrosoftVisualStudioShellInterop100Version>
     <MicrosoftVisualStudioShellInterop110Version>11.0.61030</MicrosoftVisualStudioShellInterop110Version>
     <MicrosoftVisualStudioShellInterop121DesignTimeVersion>12.1.30328</MicrosoftVisualStudioShellInterop121DesignTimeVersion>
     <MicrosoftVisualStudioShellInterop140DesignTimeVersion>14.3.25407</MicrosoftVisualStudioShellInterop140DesignTimeVersion>
-    <MicrosoftVisualStudioShellInterop150DesignTimeVersion>15.0.26507-alpha</MicrosoftVisualStudioShellInterop150DesignTimeVersion>
+    <MicrosoftVisualStudioShellInterop150DesignTimeVersion>15.0.26606-alpha</MicrosoftVisualStudioShellInterop150DesignTimeVersion>
     <MicrosoftVisualStudioShellInterop80Version>8.0.50727</MicrosoftVisualStudioShellInterop80Version>
     <MicrosoftVisualStudioShellInterop90Version>9.0.30729</MicrosoftVisualStudioShellInterop90Version>
-    <MicrosoftVisualStudioTelemetryVersion>15.0.26507-alpha</MicrosoftVisualStudioTelemetryVersion>
+    <MicrosoftVisualStudioTelemetryVersion>15.0.26606-alpha</MicrosoftVisualStudioTelemetryVersion>
     <MicrosoftVisualStudioTemplateWizardInterfaceVersion>8.0.0.0-alpha</MicrosoftVisualStudioTemplateWizardInterfaceVersion>
-    <MicrosoftVisualStudioTextDataVersion>15.0.26507-alpha</MicrosoftVisualStudioTextDataVersion>
-    <MicrosoftVisualStudioTextInternalVersion>15.0.26507-alpha</MicrosoftVisualStudioTextInternalVersion>
-    <MicrosoftVisualStudioTextLogicVersion>15.0.26507-alpha</MicrosoftVisualStudioTextLogicVersion>
-    <MicrosoftVisualStudioTextUIVersion>15.0.26507-alpha</MicrosoftVisualStudioTextUIVersion>
-    <MicrosoftVisualStudioTextUIWpfVersion>15.0.26507-alpha</MicrosoftVisualStudioTextUIWpfVersion>
+    <MicrosoftVisualStudioTextDataVersion>15.0.26606-alpha</MicrosoftVisualStudioTextDataVersion>
+    <MicrosoftVisualStudioTextInternalVersion>15.0.26606-alpha</MicrosoftVisualStudioTextInternalVersion>
+    <MicrosoftVisualStudioTextLogicVersion>15.0.26606-alpha</MicrosoftVisualStudioTextLogicVersion>
+    <MicrosoftVisualStudioTextUIVersion>15.0.26606-alpha</MicrosoftVisualStudioTextUIVersion>
+    <MicrosoftVisualStudioTextUIWpfVersion>15.0.26606-alpha</MicrosoftVisualStudioTextUIWpfVersion>
     <MicrosoftVisualStudioTextManagerInteropVersion>7.10.6070</MicrosoftVisualStudioTextManagerInteropVersion>
     <MicrosoftVisualStudioTextManagerInterop100Version>10.0.30319</MicrosoftVisualStudioTextManagerInterop100Version>
     <MicrosoftVisualStudioTextManagerInterop120Version>12.0.30110</MicrosoftVisualStudioTextManagerInterop120Version>
     <MicrosoftVisualStudioTextManagerInterop121DesignTimeVersion>12.1.30328</MicrosoftVisualStudioTextManagerInterop121DesignTimeVersion>
     <MicrosoftVisualStudioThreadingVersion>15.3.20</MicrosoftVisualStudioThreadingVersion>
-    <MicrosoftVisualStudioUtilitiesVersion>15.0.26507-alpha</MicrosoftVisualStudioUtilitiesVersion>
+    <MicrosoftVisualStudioUtilitiesVersion>15.0.26606-alpha</MicrosoftVisualStudioUtilitiesVersion>
     <MicrosoftVisualStudioValidationVersion>15.3.15</MicrosoftVisualStudioValidationVersion>
     <MicrosoftVisualStudioVsInteractiveWindowVersion>2.0.0-rc3-61304-01</MicrosoftVisualStudioVsInteractiveWindowVersion>
     <MicrosoftWin32PrimitivesVersion>4.3.0</MicrosoftWin32PrimitivesVersion>
@@ -130,7 +131,7 @@
     <MoqVersion>4.2.1402.2112</MoqVersion>
     <NerdbankFullDuplexStreamVersion>1.0.1</NerdbankFullDuplexStreamVersion>
     <NETStandardLibraryVersion>1.6.1</NETStandardLibraryVersion>
-    <NewtonsoftJsonVersion>8.0.3</NewtonsoftJsonVersion>
+    <NewtonsoftJsonVersion>9.0.1</NewtonsoftJsonVersion>
     <NuGetCommandLineVersion>2.8.5</NuGetCommandLineVersion>
     <NuGetCommandLineXPlatVersion>3.5.0-beta2-1484</NuGetCommandLineXPlatVersion>
     <NuGetVisualStudioVersion>4.0.0-rc-2048</NuGetVisualStudioVersion>
@@ -145,7 +146,7 @@
     <RoslynToolsMicrosoftVSIXExpInstallerVersion>0.4.0-beta</RoslynToolsMicrosoftVSIXExpInstallerVersion>
     <RoslynToolsReferenceAssembliesVersion>0.1.1</RoslynToolsReferenceAssembliesVersion>
     <RoslynMicrosoftVisualStudioExtensionManagerVersion>0.0.4</RoslynMicrosoftVisualStudioExtensionManagerVersion>
-    <StreamJsonRpcVersion>1.0.2-rc</StreamJsonRpcVersion>
+    <StreamJsonRpcVersion>1.1.73</StreamJsonRpcVersion>
     <SystemAppContextVersion>4.3.0</SystemAppContextVersion>
     <SystemCollectionsVersion>4.3.0</SystemCollectionsVersion>
     <SystemCollectionsConcurrentVersion>4.3.0</SystemCollectionsConcurrentVersion>
@@ -228,4 +229,4 @@
     <xunitrunnervisualstudioVersion>2.2.0-beta4-build1194</xunitrunnervisualstudioVersion>
   </PropertyGroup>
 
-</Project>
+</Project>
\ No newline at end of file
diff --git a/src/Compilers/Extension/CompilerExtension.csproj b/src/Compilers/Extension/CompilerExtension.csproj
index ee0f23cc2b85a..6612442ad6cd1 100644
--- a/src/Compilers/Extension/CompilerExtension.csproj
+++ b/src/Compilers/Extension/CompilerExtension.csproj
@@ -170,7 +170,10 @@
     </PackageReference>
     <PackageReference Include="Microsoft.VisualStudio.Utilities">
       <Version>$(MicrosoftVisualStudioUtilitiesVersion)</Version>
-    </PackageReference>
+	</PackageReference>
+    <PackageReference Include="Microsoft.VisualStudio.Shell.Interop.15.3.DesignTime">
+      <Version>$(MicrosoftVisualStudioShellInterop153DesignTimeVersion)</Version>
+	</PackageReference>
   </ItemGroup>
   <Import Project="..\..\..\build\Targets\Imports.targets" />
 </Project>
diff --git a/src/EditorFeatures/Core/Implementation/CodeFixes/CodeFixService.cs b/src/EditorFeatures/Core/Implementation/CodeFixes/CodeFixService.cs
index 11270fb4b5357..ce2ef0a7f7839 100644
--- a/src/EditorFeatures/Core/Implementation/CodeFixes/CodeFixService.cs
+++ b/src/EditorFeatures/Core/Implementation/CodeFixes/CodeFixService.cs
@@ -73,7 +73,7 @@ internal partial class CodeFixService : ForegroundThreadAffinitizedObject, ICode
             _fixAllProviderMap = ImmutableDictionary<object, FixAllProviderInfo>.Empty;
         }
 
-        public async Task<FirstDiagnosticResult> GetFirstDiagnosticWithFixAsync(
+        public async Task<FirstDiagnosticResult> GetMostSevereFixableDiagnostic(
             Document document, TextSpan range, CancellationToken cancellationToken)
         {
             if (document == null || !document.IsOpen())
@@ -83,32 +83,61 @@ internal partial class CodeFixService : ForegroundThreadAffinitizedObject, ICode
 
             using (var diagnostics = SharedPools.Default<List<DiagnosticData>>().GetPooledObject())
             {
-                var fullResult = await _diagnosticService.TryAppendDiagnosticsForSpanAsync(document, range, diagnostics.Object, cancellationToken: cancellationToken).ConfigureAwait(false);
-                foreach (var diagnostic in diagnostics.Object)
+                using (var linkedTokenSource = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken))
                 {
-                    cancellationToken.ThrowIfCancellationRequested();
-
-                    if (!range.IntersectsWith(diagnostic.TextSpan))
-                    {
-                        continue;
-                    }
+                    var linkedToken = linkedTokenSource.Token;
+
+                    // This flag is used by SuggestedActionsSource to track what solution is was
+                    // last able to get "full results" for.
+                    var isFullResult = await _diagnosticService.TryAppendDiagnosticsForSpanAsync(
+                        document, range, diagnostics.Object, cancellationToken: linkedToken).ConfigureAwait(false);
+
+                    var errorDiagnostics = diagnostics.Object.Where(d => d.Severity == DiagnosticSeverity.Error);
+                    var otherDiagnostics = diagnostics.Object.Where(d => d.Severity != DiagnosticSeverity.Error);
+
+                    // Kick off a task that will determine there's an Error Diagnostic with a fixer
+                    var errorDiagnosticsTask = Task.Run(
+                        () => GetFirstDiagnosticWithFixAsync(document, errorDiagnostics, range, linkedToken),
+                        linkedToken);
+
+                    // Kick off a task that will determine if any non-Error Diagnostic has a fixer
+                    var otherDiagnosticsTask = Task.Run(
+                        () => GetFirstDiagnosticWithFixAsync(document, otherDiagnostics, range, linkedToken),
+                        linkedToken);
+
+                    // If the error diagnostics task happens to complete with a non-null result before
+                    // the other diagnostics task, we can cancel the other task.
+                    var diagnostic = await errorDiagnosticsTask.ConfigureAwait(false)
+                        ?? await otherDiagnosticsTask.ConfigureAwait(false);
+                    linkedTokenSource.Cancel();
+
+                    return new FirstDiagnosticResult(partialResult: !isFullResult,
+                                           hasFix: diagnostic != null,
+                                           diagnostic: diagnostic);
+                }
+            }
+        }
 
-                    // REVIEW: 2 possible designs. 
-                    // 1. find the first fix and then return right away. if the lightbulb is actually expanded, find all fixes for the line synchronously. or
-                    // 2. kick off a task that finds all fixes for the given range here but return once we find the first one. 
-                    // at the same time, let the task to run to finish. if the lightbulb is expanded, we just simply use the task to get all fixes.
-                    //
-                    // first approach is simpler, so I will implement that first. if the first approach turns out to be not good enough, then
-                    // I will try the second approach which will be more complex but quicker
-                    var hasFix = await ContainsAnyFix(document, diagnostic, cancellationToken).ConfigureAwait(false);
-                    if (hasFix)
-                    {
-                        return new FirstDiagnosticResult(!fullResult, hasFix, diagnostic);
-                    }
+        private async Task<DiagnosticData> GetFirstDiagnosticWithFixAsync(
+            Document document,
+            IEnumerable<DiagnosticData> severityGroup,
+            TextSpan range,
+            CancellationToken cancellationToken)
+        {
+            foreach (var diagnostic in severityGroup)
+            {
+                if (!range.IntersectsWith(diagnostic.TextSpan))
+                {
+                    continue;
                 }
 
-                return new FirstDiagnosticResult(!fullResult, false, default(DiagnosticData));
+                if (await ContainsAnyFixAsync(document, diagnostic, cancellationToken).ConfigureAwait(false))
+                {
+                    return diagnostic;
+                }
             }
+
+            return null;
         }
 
         public async Task<ImmutableArray<CodeFixCollection>> GetFixesAsync(Document document, TextSpan range, bool includeSuppressionFixes, CancellationToken cancellationToken)
@@ -142,7 +171,7 @@ public async Task<ImmutableArray<CodeFixCollection>> GetFixesAsync(Document docu
             foreach (var spanAndDiagnostic in aggregatedDiagnostics)
             {
                 await AppendFixesAsync(
-                    document, spanAndDiagnostic.Key, spanAndDiagnostic.Value, 
+                    document, spanAndDiagnostic.Key, spanAndDiagnostic.Value,
                     result, cancellationToken).ConfigureAwait(false);
             }
 
@@ -176,7 +205,7 @@ public async Task<ImmutableArray<CodeFixCollection>> GetFixesAsync(Document docu
                 foreach (var spanAndDiagnostic in aggregatedDiagnostics)
                 {
                     await AppendSuppressionsAsync(
-                        document, spanAndDiagnostic.Key, spanAndDiagnostic.Value, 
+                        document, spanAndDiagnostic.Key, spanAndDiagnostic.Value,
                         result, cancellationToken).ConfigureAwait(false);
                 }
             }
@@ -267,7 +296,7 @@ public async Task<ImmutableArray<CodeFixCollection>> GetFixesAsync(Document docu
         }
 
         private async Task AppendSuppressionsAsync(
-            Document document, TextSpan span, IEnumerable<DiagnosticData> diagnostics, 
+            Document document, TextSpan span, IEnumerable<DiagnosticData> diagnostics,
             ArrayBuilder<CodeFixCollection> result, CancellationToken cancellationToken)
         {
             if (!_suppressionProvidersMap.TryGetValue(document.Project.Language, out var lazySuppressionProvider) || lazySuppressionProvider.Value == null)
@@ -276,10 +305,10 @@ public async Task<ImmutableArray<CodeFixCollection>> GetFixesAsync(Document docu
             }
 
             await AppendFixesOrSuppressionsAsync(
-                document, span, diagnostics, result, lazySuppressionProvider.Value, 
+                document, span, diagnostics, result, lazySuppressionProvider.Value,
                 hasFix: d => lazySuppressionProvider.Value.CanBeSuppressedOrUnsuppressed(d),
                 getFixes: dxs => lazySuppressionProvider.Value.GetSuppressionsAsync(
-                    document, span, dxs, cancellationToken), 
+                    document, span, dxs, cancellationToken),
                 cancellationToken: cancellationToken).ConfigureAwait(false);
         }
 
@@ -293,7 +322,7 @@ public async Task<ImmutableArray<CodeFixCollection>> GetFixesAsync(Document docu
             Func<ImmutableArray<Diagnostic>, Task<ImmutableArray<CodeFix>>> getFixes,
             CancellationToken cancellationToken)
         {
-            var allDiagnostics = 
+            var allDiagnostics =
                 await diagnosticsWithSameSpan.OrderByDescending(d => d.Severity)
                                              .ToDiagnosticsAsync(document.Project, cancellationToken).ConfigureAwait(false);
             var diagnostics = allDiagnostics.WhereAsArray(hasFix);
@@ -372,7 +401,7 @@ private async Task<IEnumerable<Diagnostic>> GetProjectDiagnosticsAsync(Project p
             }
         }
 
-        private async Task<bool> ContainsAnyFix(
+        private async Task<bool> ContainsAnyFixAsync(
             Document document, DiagnosticData diagnostic, CancellationToken cancellationToken)
         {
             var workspaceFixers = ImmutableArray<CodeFixProvider>.Empty;
@@ -387,7 +416,7 @@ private async Task<IEnumerable<Diagnostic>> GetProjectDiagnosticsAsync(Project p
             }
 
             Lazy<ISuppressionFixProvider> lazySuppressionProvider = null;
-            var hasSuppressionFixer = 
+            var hasSuppressionFixer =
                 _suppressionProvidersMap.TryGetValue(document.Project.Language, out lazySuppressionProvider) &&
                 lazySuppressionProvider.Value != null;
 
diff --git a/src/EditorFeatures/Core/Implementation/CodeFixes/ICodeFixService.cs b/src/EditorFeatures/Core/Implementation/CodeFixes/ICodeFixService.cs
index a1e7ff485a0fb..af2ba5c48e44a 100644
--- a/src/EditorFeatures/Core/Implementation/CodeFixes/ICodeFixService.cs
+++ b/src/EditorFeatures/Core/Implementation/CodeFixes/ICodeFixService.cs
@@ -10,9 +10,8 @@ namespace Microsoft.CodeAnalysis.CodeFixes
 {
     internal interface ICodeFixService
     {
-        Task<FirstDiagnosticResult> GetFirstDiagnosticWithFixAsync(Document document, TextSpan textSpan, CancellationToken cancellationToken);
-
         Task<ImmutableArray<CodeFixCollection>> GetFixesAsync(Document document, TextSpan textSpan, bool includeSuppressionFixes, CancellationToken cancellationToken);
         CodeFixProvider GetSuppressionFixer(string language, IEnumerable<string> diagnosticIds);
+        Task<FirstDiagnosticResult> GetMostSevereFixableDiagnostic(Document document, TextSpan range, CancellationToken cancellationToken);
     }
 }
diff --git a/src/EditorFeatures/Core/Implementation/Suggestions/SuggestedActionsSource.cs b/src/EditorFeatures/Core/Implementation/Suggestions/SuggestedActionsSource.cs
index 108795c67ae05..3a6d20e176fc6 100644
--- a/src/EditorFeatures/Core/Implementation/Suggestions/SuggestedActionsSource.cs
+++ b/src/EditorFeatures/Core/Implementation/Suggestions/SuggestedActionsSource.cs
@@ -24,14 +24,17 @@
 using Microsoft.VisualStudio.Text.Editor;
 using Roslyn.Utilities;
 
+using CodeFixGroupKey = System.Tuple<Microsoft.CodeAnalysis.Diagnostics.DiagnosticData, Microsoft.CodeAnalysis.CodeActions.CodeActionPriority>;
+
 namespace Microsoft.CodeAnalysis.Editor.Implementation.Suggestions
 {
-    using CodeFixGroupKey = Tuple<DiagnosticData, CodeActionPriority>;
 
     internal partial class SuggestedActionsSourceProvider
     {
-        private class SuggestedActionsSource : ForegroundThreadAffinitizedObject, ISuggestedActionsSource
+        private class SuggestedActionsSource : ForegroundThreadAffinitizedObject, ISuggestedActionsSource2
         {
+            private readonly ISuggestedActionCategoryRegistryService _suggestedActionCategoryRegistry;
+
             // state that will be only reset when source is disposed.
             private SuggestedActionsSourceProvider _owner;
             private ITextView _textView;
@@ -44,12 +47,17 @@ private class SuggestedActionsSource : ForegroundThreadAffinitizedObject, ISugge
 
             public event EventHandler<EventArgs> SuggestedActionsChanged;
 
-            public SuggestedActionsSource(SuggestedActionsSourceProvider owner, ITextView textView, ITextBuffer textBuffer)
+            public SuggestedActionsSource(
+                SuggestedActionsSourceProvider owner,
+                ITextView textView,
+                ITextBuffer textBuffer,
+                ISuggestedActionCategoryRegistryService suggestedActionCategoryRegistry)
             {
                 _owner = owner;
                 _textView = textView;
                 _textView.Closed += OnTextViewClosed;
                 _subjectBuffer = textBuffer;
+                _suggestedActionCategoryRegistry = suggestedActionCategoryRegistry;
                 _registration = Workspace.GetWorkspaceRegistration(textBuffer.AsTextContainer());
 
                 _lastSolutionVersionReported = InvalidSolutionVersion;
@@ -221,7 +229,7 @@ private SuggestedActionSet FilterActionSetByTitle(SuggestedActionSet set, HashSe
                 {
                     return actions.Count == 0
                         ? null
-                        : new SuggestedActionSet(actions.ToImmutable(), set.Title, set.Priority, set.ApplicableToSpan);
+                        : new SuggestedActionSet(set.CategoryName, actions.ToImmutable(), set.Title, set.Priority, set.ApplicableToSpan);
                 }
                 finally
                 {
@@ -261,7 +269,11 @@ private SuggestedActionSet InlineActions(SuggestedActionSet actionSet)
                 }
 
                 return new SuggestedActionSet(
-                    newActions.ToImmutableAndFree(), actionSet.Title, actionSet.Priority, actionSet.ApplicableToSpan);
+                    actionSet.CategoryName,
+                    newActions.ToImmutableAndFree(),
+                    actionSet.Title,
+                    actionSet.Priority,
+                    actionSet.ApplicableToSpan);
             }
 
             private ImmutableArray<SuggestedActionSet> GetCodeFixes(
@@ -529,13 +541,29 @@ private CodeRefactoring FilterOnUIThread(CodeRefactoring refactoring, Workspace
 
                         // diagnostic from things like build shouldn't reach here since we don't support LB for those diagnostics
                         Contract.Requires(diag.Item1.HasTextSpan);
-                        sets.Add(new SuggestedActionSet(group, priority, diag.Item1.TextSpan.ToSpan()));
+                        var category = GetFixCategory(diag.Item1.Severity);
+                        sets.Add(new SuggestedActionSet(category, group, priority: priority, applicableToSpan: diag.Item1.TextSpan.ToSpan()));
                     }
                 }
 
                 return sets.ToImmutableAndFree();
             }
 
+            private static string GetFixCategory(DiagnosticSeverity severity)
+            {
+                switch (severity)
+                {
+                    case DiagnosticSeverity.Hidden:
+                    case DiagnosticSeverity.Info:
+                    case DiagnosticSeverity.Warning:
+                        return PredefinedSuggestedActionCategoryNames.CodeFix;
+                    case DiagnosticSeverity.Error:
+                        return PredefinedSuggestedActionCategoryNames.ErrorFix;
+                    default:
+                        throw ExceptionUtilities.Unreachable;
+                };
+            }
+
             private static SuggestedActionSetPriority GetSuggestedActionSetPriority(CodeActionPriority key)
             {
                 switch (key)
@@ -619,87 +647,81 @@ private static SuggestedActionSetPriority GetSuggestedActionSetPriority(CodeActi
                 }
 
                 return new SuggestedActionSet(
+                    PredefinedSuggestedActionCategoryNames.Refactoring,
                     refactoringSuggestedActions.ToImmutableAndFree(),
-                    SuggestedActionSetPriority.Low,
-                    applicableSpan);
+                    priority: SuggestedActionSetPriority.Low,
+                    applicableToSpan: applicableSpan);
             }
 
-            public async Task<bool> HasSuggestedActionsAsync(
+            public Task<bool> HasSuggestedActionsAsync(
                 ISuggestedActionCategorySet requestedActionCategories,
                 SnapshotSpan range,
                 CancellationToken cancellationToken)
             {
-                var provider = _owner;
+                // We implement GetSuggestedActionCategoriesAsync so this should not be called
+                throw new NotImplementedException($"We implement {nameof(GetSuggestedActionCategoriesAsync)}. This should not be called.");
+            }
 
-                if (IsDisposed)
+            private async Task<TextSpan?> GetSpanAsync(SnapshotSpan range)
+            {
+                // First, ensure that the snapshot we're being asked about is for an actual
+                // roslyn document.  This can fail, for example, in projection scenarios where
+                // we are called with a range snapshot that refers to the projection buffer
+                // and not the actual roslyn code that is being projected into it.
+                var document = range.Snapshot.GetOpenDocumentInCurrentContextWithChanges();
+                if (document == null)
                 {
-                    // We've already been disposed.  No point in continuing.
-                    return false;
+                    return null;
                 }
 
-                using (var asyncToken = _owner.OperationListener.BeginAsyncOperation("HasSuggestedActionsAsync"))
-                {
-                    // First, ensure that the snapshot we're being asked about is for an actual
-                    // roslyn document.  This can fail, for example, in projection scenarios where
-                    // we are called with a range snapshot that refers to the projection buffer
-                    // and not the actual roslyn code that is being projected into it.
-                    var document = range.Snapshot.GetOpenDocumentInCurrentContextWithChanges();
-                    if (document == null)
-                    {
-                        return false;
-                    }
-
-                    // Next, before we do any async work, acquire the user's selection, directly grabbing
-                    // it from the UI thread if htat's what we're on. That way we don't have any reentrancy
-                    // blocking concerns if VS wants to block on this call (for example, if the user 
-                    // explicitly invokes the 'show smart tag' command).
-                    //
-                    // This work must happen on the UI thread as it needs to access the _textView's mutable
-                    // state.
-                    //
-                    // Note: we may be called in one of two VS scenarios:
-                    //      1) User has moved caret to a new line.  In this case VS will call into us in the
-                    //         bg to see if we have any suggested actions for this line.  In order to figure
-                    //         this out, we need to see what selectoin the user has (for refactorings), which
-                    //         necessitates going back to the fg.
-                    //
-                    //      2) User moves to a line and immediately hits ctrl-dot.  In this case, on the UI
-                    //         thread VS will kick us off and then immediately block to get the results so
-                    //         that they can expand the lightbulb.  In this case we cannot do BG work first,
-                    //         then call back into the UI thread to try to get the user selection.  This will
-                    //         deadlock as the UI thread is blocked on us.  
-                    //
-                    // There are two solution to '2'.  Either introduce reentrancy (which we really don't
-                    // like to do), or just ensure that we acquire and get the users selection up front.
-                    // This means that when we're called from the UI therad, we never try to go back to the
-                    // UI thread.
-                    TextSpan? selection = null;
-                    if (IsForeground())
-                    {
-                        selection = TryGetCodeRefactoringSelection(range);
-                    }
-                    else
+                // Next, before we do any async work, acquire the user's selection, directly grabbing
+                // it from the UI thread if htat's what we're on. That way we don't have any reentrancy
+                // blocking concerns if VS wants to block on this call (for example, if the user 
+                // explicitly invokes the 'show smart tag' command).
+                //
+                // This work must happen on the UI thread as it needs to access the _textView's mutable
+                // state.
+                //
+                // Note: we may be called in one of two VS scenarios:
+                //      1) User has moved caret to a new line.  In this case VS will call into us in the
+                //         bg to see if we have any suggested actions for this line.  In order to figure
+                //         this out, we need to see what selectoin the user has (for refactorings), which
+                //         necessitates going back to the fg.
+                //
+                //      2) User moves to a line and immediately hits ctrl-dot.  In this case, on the UI
+                //         thread VS will kick us off and then immediately block to get the results so
+                //         that they can expand the lightbulb.  In this case we cannot do BG work first,
+                //         then call back into the UI thread to try to get the user selection.  This will
+                //         deadlock as the UI thread is blocked on us.  
+                //
+                // There are two solution to '2'.  Either introduce reentrancy (which we really don't
+                // like to do), or just ensure that we acquire and get the users selection up front.
+                // This means that when we're called from the UI therad, we never try to go back to the
+                // UI thread.
+                TextSpan? selection = null;
+                if (IsForeground())
+                {
+                    selection = TryGetCodeRefactoringSelection(range);
+                }
+                else
+                {
+                    await InvokeBelowInputPriority(() =>
                     {
-                        await InvokeBelowInputPriority(() =>
+                        // Make sure we were not disposed between kicking off this work and getting
+                        // to this point.
+                        if (IsDisposed)
                         {
-                            // Make sure we were not disposed between kicking off this work and getting
-                            // to this point.
-                            if (IsDisposed)
-                            {
-                                return;
-                            }
-
-                            selection = TryGetCodeRefactoringSelection(range);
-                        }).ConfigureAwait(false);
-                    }
+                            return;
+                        }
 
-                    return
-                        await HasFixesAsync(provider, document, range, cancellationToken).ConfigureAwait(false) ||
-                        await HasRefactoringsAsync(provider, document, selection, cancellationToken).ConfigureAwait(false);
+                        selection = TryGetCodeRefactoringSelection(range);
+                    }).ConfigureAwait(false);
                 }
+
+                return selection;
             }
 
-            private async Task<bool> HasFixesAsync(
+            private async Task<string> GetFixLevelAsync(
                 SuggestedActionsSourceProvider provider,
                 Document document,
                 SnapshotSpan range,
@@ -712,28 +734,28 @@ private static SuggestedActionSetPriority GetSuggestedActionSetPriority(CodeActi
                     supportsFeatureService.SupportsCodeFixes(document))
                 {
                     var result = await Task.Run(
-                        () => provider._codeFixService.GetFirstDiagnosticWithFixAsync(
+                        () => provider._codeFixService.GetMostSevereFixableDiagnostic(
                             document, range.Span.ToTextSpan(), cancellationToken),
                             cancellationToken).ConfigureAwait(false);
 
                     if (result.HasFix)
                     {
                         Logger.Log(FunctionId.SuggestedActions_HasSuggestedActionsAsync);
-                        return true;
+                        return GetFixCategory(result.Diagnostic.Severity);
                     }
 
                     if (result.PartialResult)
                     {
                         // reset solution version number so that we can raise suggested action changed event
                         Volatile.Write(ref _lastSolutionVersionReported, InvalidSolutionVersion);
-                        return false;
+                        return null;
                     }
                 }
 
-                return false;
+                return null;
             }
 
-            private async Task<bool> HasRefactoringsAsync(
+            private async Task<string> TryGetRefactoringSuggestedActionCategoryAsync(
                 SuggestedActionsSourceProvider provider,
                 Document document,
                 TextSpan? selection,
@@ -743,7 +765,7 @@ private static SuggestedActionSetPriority GetSuggestedActionSetPriority(CodeActi
                 {
                     // this is here to fail test and see why it is failed.
                     Trace.WriteLine("given range is not current");
-                    return false;
+                    return null;
                 }
 
                 var workspace = document.Project.Solution.Workspace;
@@ -753,13 +775,16 @@ private static SuggestedActionSetPriority GetSuggestedActionSetPriority(CodeActi
                     provider._codeRefactoringService != null &&
                     supportsFeatureService.SupportsRefactorings(document))
                 {
-                    return await Task.Run(
+                    if (await Task.Run(
                         () => provider._codeRefactoringService.HasRefactoringsAsync(
                             document, selection.Value, cancellationToken),
-                        cancellationToken).ConfigureAwait(false);
+                        cancellationToken).ConfigureAwait(false))
+                    {
+                        return PredefinedSuggestedActionCategoryNames.Refactoring;
+                    }
                 }
 
-                return false;
+                return null;
             }
 
             private TextSpan? TryGetCodeRefactoringSelection(SnapshotSpan range)
@@ -860,6 +885,40 @@ private void OnSuggestedActionsChanged(Workspace currentWorkspace, DocumentId cu
 
                 Volatile.Write(ref _lastSolutionVersionReported, solutionVersion);
             }
+
+            public async Task<ISuggestedActionCategorySet> GetSuggestedActionCategoriesAsync(ISuggestedActionCategorySet requestedActionCategories, SnapshotSpan range, CancellationToken cancellationToken)
+            {
+                var provider = _owner;
+                using (var asyncToken = _owner.OperationListener.BeginAsyncOperation(nameof(GetSuggestedActionCategoriesAsync)))
+                {
+                    var selection = await GetSpanAsync(range).ConfigureAwait(false);
+                    if (selection != null)
+                    {
+                        var document = range.Snapshot.GetOpenDocumentInCurrentContextWithChanges();
+                        using (var linkedTokenSource = CancellationTokenSource.CreateLinkedTokenSource(cancellationToken))
+                        {
+                            var linkedToken = linkedTokenSource.Token;
+
+                            var errorTask = Task.Run(
+                                () => GetFixLevelAsync(provider, document, range, linkedToken), linkedToken);
+
+                            var refactoringTask = Task.Run(
+                                () => TryGetRefactoringSuggestedActionCategoryAsync(provider, document, selection, linkedToken),
+                                linkedToken);
+
+                            // If we happen to get the result of the error task before the refactoring task,
+                            // and that result is non-null, we can just cancel the refactoring task.
+                            var result = await errorTask.ConfigureAwait(false) ?? await refactoringTask.ConfigureAwait(false);
+                            linkedTokenSource.Cancel();
+                            return result == null
+                                ? null
+                                : _suggestedActionCategoryRegistry.CreateSuggestedActionCategorySet(result);
+                        }
+                    }
+                }
+
+                return null;
+            }
         }
     }
 }
\ No newline at end of file
diff --git a/src/EditorFeatures/Core/Implementation/Suggestions/SuggestedActionsSourceProvider.cs b/src/EditorFeatures/Core/Implementation/Suggestions/SuggestedActionsSourceProvider.cs
index 41559e3c9cf1d..b83464677172d 100644
--- a/src/EditorFeatures/Core/Implementation/Suggestions/SuggestedActionsSourceProvider.cs
+++ b/src/EditorFeatures/Core/Implementation/Suggestions/SuggestedActionsSourceProvider.cs
@@ -35,6 +35,7 @@ internal partial class SuggestedActionsSourceProvider : ISuggestedActionsSourceP
         private readonly ICodeRefactoringService _codeRefactoringService;
         private readonly IDiagnosticAnalyzerService _diagnosticService;
         private readonly ICodeFixService _codeFixService;
+        private readonly ISuggestedActionCategoryRegistryService _suggestedActionCategoryRegistry;
 
         public readonly ICodeActionEditHandlerService EditHandler;
         public readonly IAsynchronousOperationListener OperationListener;
@@ -50,6 +51,7 @@ internal partial class SuggestedActionsSourceProvider : ISuggestedActionsSourceP
             ICodeFixService codeFixService,
             ICodeActionEditHandlerService editHandler,
             IWaitIndicator waitIndicator,
+            ISuggestedActionCategoryRegistryService suggestedActionCategoryRegistry,
             [ImportMany] IEnumerable<Lazy<IAsynchronousOperationListener, FeatureMetadata>> asyncListeners,
             [ImportMany] IEnumerable<Lazy<IImageMonikerService, OrderableMetadata>> imageMonikerServices,
             [ImportMany] IEnumerable<Lazy<ISuggestedActionCallback>> actionCallbacks)
@@ -57,6 +59,7 @@ internal partial class SuggestedActionsSourceProvider : ISuggestedActionsSourceP
             _codeRefactoringService = codeRefactoringService;
             _diagnosticService = diagnosticService;
             _codeFixService = codeFixService;
+            _suggestedActionCategoryRegistry = suggestedActionCategoryRegistry;
             ActionCallbacks = actionCallbacks.ToImmutableArray();
             EditHandler = editHandler;
             WaitIndicator = waitIndicator;
@@ -70,7 +73,7 @@ public ISuggestedActionsSource CreateSuggestedActionsSource(ITextView textView,
             Contract.ThrowIfNull(textView);
             Contract.ThrowIfNull(textBuffer);
 
-            return new SuggestedActionsSource(this, textView, textBuffer);
+            return new SuggestedActionsSource(this, textView, textBuffer, _suggestedActionCategoryRegistry);
         }
     }
 }
\ No newline at end of file
diff --git a/src/EditorFeatures/Test/CodeFixes/CodeFixServiceTests.cs b/src/EditorFeatures/Test/CodeFixes/CodeFixServiceTests.cs
index 564dfbe919935..1d16af7d78a3f 100644
--- a/src/EditorFeatures/Test/CodeFixes/CodeFixServiceTests.cs
+++ b/src/EditorFeatures/Test/CodeFixes/CodeFixServiceTests.cs
@@ -46,7 +46,7 @@ public async Task TestGetFirstDiagnosticWithFixAsync()
                 var reference = new MockAnalyzerReference();
                 var project = workspace.CurrentSolution.Projects.Single().AddAnalyzerReference(reference);
                 var document = project.Documents.Single();
-                var unused = await fixService.GetFirstDiagnosticWithFixAsync(document, TextSpan.FromBounds(0, 0), cancellationToken: CancellationToken.None);
+                var unused = await fixService.GetMostSevereFixableDiagnostic(document, TextSpan.FromBounds(0, 0), cancellationToken: CancellationToken.None);
 
                 var fixer1 = fixers.Single().Value as MockFixer;
                 var fixer2 = reference.Fixer as MockFixer;
@@ -127,7 +127,7 @@ public async Task GetFirstDiagnosticWithFixAsync(CodeFixProvider codefix)
             using (var workspace = tuple.Item1)
             {
                 GetDocumentAndExtensionManager(tuple.Item2, workspace, out var document, out var extensionManager);
-                var unused = await tuple.Item3.GetFirstDiagnosticWithFixAsync(document, TextSpan.FromBounds(0, 0), cancellationToken: CancellationToken.None);
+                var unused = await tuple.Item3.GetMostSevereFixableDiagnostic(document, TextSpan.FromBounds(0, 0), cancellationToken: CancellationToken.None);
                 Assert.True(extensionManager.IsDisabled(codefix));
                 Assert.False(extensionManager.IsIgnored(codefix));
             }
diff --git a/src/EditorFeatures/TestUtilities/TextEditorFactoryExtensions.cs b/src/EditorFeatures/TestUtilities/TextEditorFactoryExtensions.cs
index 0332c0c778e8f..228928231472a 100644
--- a/src/EditorFeatures/TestUtilities/TextEditorFactoryExtensions.cs
+++ b/src/EditorFeatures/TestUtilities/TextEditorFactoryExtensions.cs
@@ -15,7 +15,17 @@ public static DisposableTextView CreateDisposableTextView(this ITextEditorFactor
 
         public static DisposableTextView CreateDisposableTextView(this ITextEditorFactoryService textEditorFactory, ITextBuffer buffer)
         {
-            return new DisposableTextView(textEditorFactory.CreateTextView(buffer));
+            // Every default role but outlining. Starting in 15.2, the editor
+            // OutliningManager imports JoinableTaskContext in a way that's 
+            // difficult to satisfy in our unit tests. Since we don't directly
+            // depend on it, just disable it
+            var roles = textEditorFactory.CreateTextViewRoleSet(PredefinedTextViewRoles.Analyzable,
+                PredefinedTextViewRoles.Document,
+                PredefinedTextViewRoles.Editable,
+                PredefinedTextViewRoles.Interactive,
+                PredefinedTextViewRoles.Zoomable);
+
+            return new DisposableTextView(textEditorFactory.CreateTextView(buffer, roles));
         }
     }
 
diff --git a/src/EditorFeatures/TestUtilities/Workspaces/TestHostDocument.cs b/src/EditorFeatures/TestUtilities/Workspaces/TestHostDocument.cs
index ff7fc26918752..1c6cf7ee88bc8 100644
--- a/src/EditorFeatures/TestUtilities/Workspaces/TestHostDocument.cs
+++ b/src/EditorFeatures/TestUtilities/Workspaces/TestHostDocument.cs
@@ -203,7 +203,18 @@ public IWpfTextView GetTextView()
 
                 WpfTestCase.RequireWpfFact($"Creates an IWpfTextView through {nameof(TestHostDocument)}.{nameof(GetTextView)}");
 
-                _textView = _exportProvider.GetExportedValue<ITextEditorFactoryService>().CreateTextView(this.TextBuffer);
+                var factory = _exportProvider.GetExportedValue<ITextEditorFactoryService>();
+                
+                // Every default role but outlining. Starting in 15.2, the editor
+                // OutliningManager imports JoinableTaskContext in a way that's 
+                // difficult to satisfy in our unit tests. Since we don't directly
+                // depend on it, just disable it
+                var roles = factory.CreateTextViewRoleSet(PredefinedTextViewRoles.Analyzable, 
+                    PredefinedTextViewRoles.Document, 
+                    PredefinedTextViewRoles.Editable, 
+                    PredefinedTextViewRoles.Interactive, 
+                    PredefinedTextViewRoles.Zoomable);
+                _textView = factory.CreateTextView(this.TextBuffer, roles);
                 if (this.CursorPosition.HasValue)
                 {
                     _textView.Caret.MoveTo(new SnapshotPoint(_textView.TextSnapshot, CursorPosition.Value));
diff --git a/src/Tools/GenerateSdkPackages/files.txt b/src/Tools/GenerateSdkPackages/files.txt
index bfd99fbcac996..211d399331408 100644
--- a/src/Tools/GenerateSdkPackages/files.txt
+++ b/src/Tools/GenerateSdkPackages/files.txt
@@ -20,6 +20,7 @@ Microsoft.VisualStudio.Utilities.dll
 Microsoft.VisualStudio.Platform.VSEditor.dll
 Microsoft.VisualStudio.Platform.VSEditor.Interop.dll
 Microsoft.VisualStudio.Shell.Interop.15.0.DesignTime.dll
+Microsoft.VisualStudio.Shell.Interop.15.3.DesignTime.dll
 Microsoft.Internal.Performance.CodeMarkers.DesignTime.dll
 PackageAndDeploy\Microsoft.VisualStudio.Shell.Framework.dll
 PackageAndDeploy\Microsoft.VisualStudio.Shell.15.0.dll
diff --git a/src/VisualStudio/Core/Def/ServicesVisualStudio.csproj b/src/VisualStudio/Core/Def/ServicesVisualStudio.csproj
index f3d937caeaeba..5067772950679 100644
--- a/src/VisualStudio/Core/Def/ServicesVisualStudio.csproj
+++ b/src/VisualStudio/Core/Def/ServicesVisualStudio.csproj
@@ -345,6 +345,9 @@
     </PackageReference>
     <PackageReference Include="Microsoft.VisualStudio.Shell.Interop.15.0.DesignTime">
       <Version>$(MicrosoftVisualStudioShellInterop150DesignTimeVersion)</Version>
+    </PackageReference>
+	 <PackageReference Include="Microsoft.VisualStudio.Shell.Interop.15.3.DesignTime">
+      <Version>$(MicrosoftVisualStudioShellInterop153DesignTimeVersion)</Version>
     </PackageReference>
     <PackageReference Include="Microsoft.VisualStudio.Shell.15.0">
       <Version>$(MicrosoftVisualStudioShell150Version)</Version>
diff --git a/src/VisualStudio/Core/Next/ServicesVisualStudio.Next.csproj b/src/VisualStudio/Core/Next/ServicesVisualStudio.Next.csproj
index 226aa9490b044..56c9cfa3fa1e2 100644
--- a/src/VisualStudio/Core/Next/ServicesVisualStudio.Next.csproj
+++ b/src/VisualStudio/Core/Next/ServicesVisualStudio.Next.csproj
@@ -126,6 +126,15 @@
     <PackageReference Include="Microsoft.VisualStudio.Diagnostics.PerformanceProvider">
       <Version>$(MicrosoftVisualStudioDiagnosticsPerformanceProviderVersion)</Version>
     </PackageReference>
+	<PackageReference Include="Microsoft.VisualStudio.Shell.Interop.15.3.DesignTime">
+      <Version>$(MicrosoftVisualStudioShellInterop153DesignTimeVersion)</Version>
+    </PackageReference>
+	<PackageReference Include="StreamJsonRPC">
+      <Version>$(StreamJsonRPCVersion)</Version>
+    </PackageReference>
+	<PackageReference Include="Microsoft.VisualStudio.Threading">
+      <Version>$(MicrosoftVisualStudioThreadingVersion)</Version>
+    </PackageReference>	
   </ItemGroup>
   <ItemGroup>
     <PublicAPI Include="PublicAPI.Shipped.txt" />

From 064d3ebee4b81eeac9225fa2eb76da719ba93686 Mon Sep 17 00:00:00 2001
From: Ravi Chande <rchande@microsoft.com>
Date: Mon, 31 Jul 2017 14:29:38 -0700
Subject: [PATCH 07/77] Add missing files

---
 src/EditorFeatures/Core/EditorFeatures.csproj |  3 +
 .../NavigableSymbolService.NavigableSymbol.cs | 61 +++++++++++++++
 ...ableSymbolService.NavigableSymbolSource.cs | 76 +++++++++++++++++++
 .../Core/NavigableSymbolService.cs            | 39 ++++++++++
 4 files changed, 179 insertions(+)
 create mode 100644 src/EditorFeatures/Core/NavigableSymbolService.NavigableSymbol.cs
 create mode 100644 src/EditorFeatures/Core/NavigableSymbolService.NavigableSymbolSource.cs
 create mode 100644 src/EditorFeatures/Core/NavigableSymbolService.cs

diff --git a/src/EditorFeatures/Core/EditorFeatures.csproj b/src/EditorFeatures/Core/EditorFeatures.csproj
index 304c7df634c70..05b3a8c7f84f5 100644
--- a/src/EditorFeatures/Core/EditorFeatures.csproj
+++ b/src/EditorFeatures/Core/EditorFeatures.csproj
@@ -173,6 +173,9 @@
     <Compile Include="Implementation\Intellisense\QuickInfo\Providers\LinkedFileDiscrepancyException.cs" />
     <Compile Include="Implementation\Intellisense\Completion\CompletionFilterReason.cs" />
     <Compile Include="Implementation\Intellisense\Completion\FilterResult.cs" />
+    <Compile Include="NavigableSymbols\NavigableSymbolService.cs" />
+    <Compile Include="NavigableSymbols\NavigableSymbolService.NavigableSymbol.cs" />
+    <Compile Include="NavigableSymbols\NavigableSymbolService.NavigableSymbolSource.cs" />
     <Compile Include="ReferenceHighlighting\IDocumentHighlightsService.cs" />
     <Compile Include="Implementation\Structure\BlockTagState.cs" />
     <Compile Include="Implementation\Suggestions\ISuggestedActionCallback.cs" />
diff --git a/src/EditorFeatures/Core/NavigableSymbolService.NavigableSymbol.cs b/src/EditorFeatures/Core/NavigableSymbolService.NavigableSymbol.cs
new file mode 100644
index 0000000000000..94921c91aca09
--- /dev/null
+++ b/src/EditorFeatures/Core/NavigableSymbolService.NavigableSymbol.cs
@@ -0,0 +1,61 @@
+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using Microsoft.CodeAnalysis.Editor.GoToDefinition;
+using Microsoft.CodeAnalysis.Editor.Host;
+using Microsoft.CodeAnalysis.FindUsages;
+using Microsoft.VisualStudio.Language.Intellisense;
+using Microsoft.VisualStudio.Text;
+using Roslyn.Utilities;
+
+namespace Microsoft.CodeAnalysis.Editor.NavigableSymbols
+{
+    internal partial class NavigableSymbolService
+    {
+        private class NavigableSymbol : INavigableSymbol
+        {
+            private readonly ImmutableArray<DefinitionItem> _definitions;
+            private readonly SnapshotSpan _span;
+            private readonly Document _document;
+            private readonly IEnumerable<Lazy<IStreamingFindUsagesPresenter>> _presenters;
+            private readonly IWaitIndicator _waitIndicator;
+
+            public NavigableSymbol(
+                ImmutableArray<DefinitionItem> definitions,
+                SnapshotSpan span,
+                Document document,
+                IEnumerable<Lazy<IStreamingFindUsagesPresenter>> streamingPresenters,
+                IWaitIndicator waitIndicator)
+            {
+                Contract.ThrowIfFalse(definitions.Length > 0);
+
+                _definitions = definitions;
+                _span = span;
+                _document = document;
+                _presenters = streamingPresenters;
+                _waitIndicator = waitIndicator;
+            }
+
+            public SnapshotSpan SymbolSpan => _span;
+
+            public IEnumerable<INavigableRelationship> Relationships =>
+                SpecializedCollections.SingletonEnumerable(PredefinedNavigableRelationships.Definition);
+
+            public void Navigate(INavigableRelationship relationship) =>
+                _waitIndicator.Wait(
+                    title: EditorFeaturesResources.Go_to_Definition,
+                    message: EditorFeaturesResources.Navigating_to_definition,
+                    allowCancel: true,
+                    showProgress: false,
+                    action: context => GoToDefinitionHelpers.TryGoToDefinition(
+                        _definitions,
+                        _document.Project,
+                        _definitions[0].NameDisplayParts.GetFullText(),
+                        _presenters,
+                        context.CancellationToken)
+                    );
+        }
+    }
+}
diff --git a/src/EditorFeatures/Core/NavigableSymbolService.NavigableSymbolSource.cs b/src/EditorFeatures/Core/NavigableSymbolService.NavigableSymbolSource.cs
new file mode 100644
index 0000000000000..418279a87be0a
--- /dev/null
+++ b/src/EditorFeatures/Core/NavigableSymbolService.NavigableSymbolSource.cs
@@ -0,0 +1,76 @@
+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.CodeAnalysis.Editor.GoToDefinition;
+using Microsoft.CodeAnalysis.Editor.Host;
+using Microsoft.CodeAnalysis.Shared.Extensions;
+using Microsoft.CodeAnalysis.Text;
+using Microsoft.VisualStudio.Language.Intellisense;
+using Microsoft.VisualStudio.Text;
+using Microsoft.VisualStudio.Text.Editor;
+
+namespace Microsoft.CodeAnalysis.Editor.NavigableSymbols
+{
+    internal partial class NavigableSymbolService
+    {
+        private partial class NavigableSymbolSource : INavigableSymbolSource
+        {
+            private readonly IEnumerable<Lazy<IStreamingFindUsagesPresenter>> _presenters;
+            private readonly IWaitIndicator _waitIndicator;
+
+            private bool _disposed;
+
+            public NavigableSymbolSource(
+                IEnumerable<Lazy<IStreamingFindUsagesPresenter>> streamingPresenters,
+                IWaitIndicator waitIndicator)
+            {
+                _presenters = streamingPresenters;
+                _waitIndicator = waitIndicator;
+            }
+
+            public void Dispose()
+            {
+                _disposed = true;
+            }
+
+            public async Task<INavigableSymbol> GetNavigableSymbolAsync(SnapshotSpan triggerSpan, CancellationToken cancellationToken)
+            {
+                if (_disposed)
+                {
+                    return null;
+                }
+
+                var snapshot = triggerSpan.Snapshot;
+                var position = triggerSpan.Start;
+                var document = snapshot.GetOpenDocumentInCurrentContextWithChanges();
+                if (document == null)
+                {
+                    return null;
+                }
+
+                var service = document.GetLanguageService<IGoToSymbolService>();
+
+                var context = new GoToDefinitionContext(
+                    document, 
+                    position, 
+                    cancellationToken: cancellationToken);
+
+                await service.GetDefinitionsAsync(context).ConfigureAwait(false);
+
+                if (!context.Items.TryGetValue(WellKnownDefinitionTypes.Definition, out var definitions))
+                {
+                    return null;
+                }
+
+                var span = context.Span;
+                var snapshotSpan = new SnapshotSpan(snapshot, span.Start, span.Length);
+                return new NavigableSymbol(definitions.ToImmutableArray(), snapshotSpan, document, _presenters, _waitIndicator);
+            }
+        }
+    }
+}
diff --git a/src/EditorFeatures/Core/NavigableSymbolService.cs b/src/EditorFeatures/Core/NavigableSymbolService.cs
new file mode 100644
index 0000000000000..c1b6c945ea297
--- /dev/null
+++ b/src/EditorFeatures/Core/NavigableSymbolService.cs
@@ -0,0 +1,39 @@
+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.Composition;
+using Microsoft.CodeAnalysis.Editor.Host;
+using Microsoft.CodeAnalysis.Editor.Shared.Extensions;
+using Microsoft.VisualStudio.Language.Intellisense;
+using Microsoft.VisualStudio.Text;
+using Microsoft.VisualStudio.Text.Editor;
+using Microsoft.VisualStudio.Utilities;
+
+namespace Microsoft.CodeAnalysis.Editor.NavigableSymbols
+{
+    [Export(typeof(INavigableSymbolSourceProvider))]
+    [Name(nameof(NavigableSymbolService))]
+    [ContentType(ContentTypeNames.RoslynContentType)]
+    internal partial class NavigableSymbolService : INavigableSymbolSourceProvider
+    {
+        private static readonly object s_key = new object();
+        private readonly IEnumerable<Lazy<IStreamingFindUsagesPresenter>> _streamingPresenters;
+        private readonly IWaitIndicator _waitIndicator;
+
+        [ImportingConstructor]
+        public NavigableSymbolService(
+            IWaitIndicator waitIndicator,
+            [ImportMany] IEnumerable<Lazy<IStreamingFindUsagesPresenter>> streamingPresenters)
+        {
+            _waitIndicator = waitIndicator;
+            _streamingPresenters = streamingPresenters;
+        }
+
+        public INavigableSymbolSource TryCreateNavigableSymbolSource(ITextView textView, ITextBuffer buffer)
+        {
+            return textView.GetOrCreatePerSubjectBufferProperty(buffer, s_key,
+                (v, b) => new NavigableSymbolSource(_streamingPresenters, _waitIndicator));
+        }
+    }
+}

From e524549801ed909441155f48e378bf3dbe4617b4 Mon Sep 17 00:00:00 2001
From: Ravi Chande <rchande@microsoft.com>
Date: Mon, 31 Jul 2017 14:29:47 -0700
Subject: [PATCH 08/77] Use Multidictionary

---
 .../GoToDefinition/GoToDefinitionContext.cs    | 18 ++++++++++--------
 ...gableSymbolService.NavigableSymbolSource.cs |  2 +-
 2 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/src/EditorFeatures/Core/GoToDefinition/GoToDefinitionContext.cs b/src/EditorFeatures/Core/GoToDefinition/GoToDefinitionContext.cs
index 40f576903bf65..f27b2323c5e4d 100644
--- a/src/EditorFeatures/Core/GoToDefinition/GoToDefinitionContext.cs
+++ b/src/EditorFeatures/Core/GoToDefinition/GoToDefinitionContext.cs
@@ -4,6 +4,7 @@
 using System.Threading;
 using Microsoft.CodeAnalysis.FindUsages;
 using Microsoft.CodeAnalysis.Text;
+using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.Editor.GoToDefinition
 {
@@ -11,7 +12,7 @@ internal class GoToDefinitionContext
     {
         private readonly object _gate = new object();
 
-        private readonly Dictionary<string, List<DefinitionItem>> _items = new Dictionary<string, List<DefinitionItem>>();
+        private readonly MultiDictionary<string, DefinitionItem> _items = new MultiDictionary<string, DefinitionItem>();
 
         public GoToDefinitionContext(Document document, int position, CancellationToken cancellationToken)
         {
@@ -24,19 +25,20 @@ public GoToDefinitionContext(Document document, int position, CancellationToken
         public int Position { get; }
         public CancellationToken CancellationToken { get; }
 
-        public IReadOnlyDictionary<string, List<DefinitionItem>> Items => _items;
+        public IReadOnlyDictionary<string, List<DefinitionItem>> Items => null;// _items;
         public TextSpan Span { get; set; }
 
+        public bool TryGetItems(string key, out IEnumerable<DefinitionItem> items)
+        {
+            items = _items[key];
+            return items != null;
+        }
+
         public void AddItem(string key, DefinitionItem item)
         {
             lock (_gate)
             {
-                if (!_items.ContainsKey(key))
-                {
-                    _items[key] = new List<DefinitionItem>();
-                }
-
-                _items[key].Add(item);
+                _items.Add(key, item);
             }
         }
     }
diff --git a/src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.NavigableSymbolSource.cs b/src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.NavigableSymbolSource.cs
index 418279a87be0a..97c134d024cf3 100644
--- a/src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.NavigableSymbolSource.cs
+++ b/src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.NavigableSymbolSource.cs
@@ -62,7 +62,7 @@ public async Task<INavigableSymbol> GetNavigableSymbolAsync(SnapshotSpan trigger
 
                 await service.GetDefinitionsAsync(context).ConfigureAwait(false);
 
-                if (!context.Items.TryGetValue(WellKnownDefinitionTypes.Definition, out var definitions))
+                if (!context.TryGetItems(WellKnownDefinitionTypes.Definition, out var definitions))
                 {
                     return null;
                 }

From 8974160543ebb61d6a5a2e77a079958122df0360 Mon Sep 17 00:00:00 2001
From: Ravi Chande <rchande@microsoft.com>
Date: Mon, 31 Jul 2017 14:30:27 -0700
Subject: [PATCH 09/77] Remove unecessary named arg

---
 .../NavigableSymbolService.NavigableSymbolSource.cs          | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.NavigableSymbolSource.cs b/src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.NavigableSymbolSource.cs
index 97c134d024cf3..a8776d5d31bfb 100644
--- a/src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.NavigableSymbolSource.cs
+++ b/src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.NavigableSymbolSource.cs
@@ -55,10 +55,7 @@ public async Task<INavigableSymbol> GetNavigableSymbolAsync(SnapshotSpan trigger
 
                 var service = document.GetLanguageService<IGoToSymbolService>();
 
-                var context = new GoToDefinitionContext(
-                    document, 
-                    position, 
-                    cancellationToken: cancellationToken);
+                var context = new GoToDefinitionContext(document, position, cancellationToken);
 
                 await service.GetDefinitionsAsync(context).ConfigureAwait(false);
 

From bf32497a8ee565080d91fac5384973827d5ec98c Mon Sep 17 00:00:00 2001
From: Ravi Chande <rchande@microsoft.com>
Date: Mon, 31 Jul 2017 14:31:01 -0700
Subject: [PATCH 10/77] Use ToSpan helper

---
 .../NavigableSymbolService.NavigableSymbolSource.cs           | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.NavigableSymbolSource.cs b/src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.NavigableSymbolSource.cs
index a8776d5d31bfb..2211beabe5c9e 100644
--- a/src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.NavigableSymbolSource.cs
+++ b/src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.NavigableSymbolSource.cs
@@ -10,6 +10,7 @@
 using Microsoft.CodeAnalysis.Editor.Host;
 using Microsoft.CodeAnalysis.Shared.Extensions;
 using Microsoft.CodeAnalysis.Text;
+using Microsoft.CodeAnalysis.Text.Shared.Extensions;
 using Microsoft.VisualStudio.Language.Intellisense;
 using Microsoft.VisualStudio.Text;
 using Microsoft.VisualStudio.Text.Editor;
@@ -64,8 +65,7 @@ public async Task<INavigableSymbol> GetNavigableSymbolAsync(SnapshotSpan trigger
                     return null;
                 }
 
-                var span = context.Span;
-                var snapshotSpan = new SnapshotSpan(snapshot, span.Start, span.Length);
+                var snapshotSpan = new SnapshotSpan(snapshot, context.Span.ToSpan());
                 return new NavigableSymbol(definitions.ToImmutableArray(), snapshotSpan, document, _presenters, _waitIndicator);
             }
         }

From 24074bdc59d85bb72c380c137181c2d9e8c47556 Mon Sep 17 00:00:00 2001
From: Ravi Chande <rchande@microsoft.com>
Date: Mon, 31 Jul 2017 14:32:13 -0700
Subject: [PATCH 11/77] Clean up unused usings

---
 .../GoToDefinition/AbstractGoToDefinitionItemService.cs     | 5 -----
 .../GoToDefinition/AbstractGoToDefinitionSymbolService.cs   | 1 -
 .../Core/GoToDefinition/IGoToDefinitionService.cs           | 1 -
 .../Core/GoToDefinition/IGoToSymbolService.cs               | 6 ------
 .../Core/GoToDefinition/WellKnownDefinitionTypes.cs         | 1 -
 5 files changed, 14 deletions(-)

diff --git a/src/EditorFeatures/Core/GoToDefinition/AbstractGoToDefinitionItemService.cs b/src/EditorFeatures/Core/GoToDefinition/AbstractGoToDefinitionItemService.cs
index 7b74101ecab65..01d6e66312754 100644
--- a/src/EditorFeatures/Core/GoToDefinition/AbstractGoToDefinitionItemService.cs
+++ b/src/EditorFeatures/Core/GoToDefinition/AbstractGoToDefinitionItemService.cs
@@ -1,12 +1,7 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
-using System.Collections.Immutable;
-using System.Threading;
 using System.Threading.Tasks;
-using Microsoft.CodeAnalysis.Editor.FindUsages;
 using Microsoft.CodeAnalysis.Editor.Shared.Utilities;
-using Microsoft.CodeAnalysis.FindUsages;
-using Microsoft.CodeAnalysis.Host.Mef;
 using Microsoft.CodeAnalysis.Shared.Extensions;
 
 namespace Microsoft.CodeAnalysis.Editor.GoToDefinition
diff --git a/src/EditorFeatures/Core/GoToDefinition/AbstractGoToDefinitionSymbolService.cs b/src/EditorFeatures/Core/GoToDefinition/AbstractGoToDefinitionSymbolService.cs
index ef984af83835c..f6c7eece0f552 100644
--- a/src/EditorFeatures/Core/GoToDefinition/AbstractGoToDefinitionSymbolService.cs
+++ b/src/EditorFeatures/Core/GoToDefinition/AbstractGoToDefinitionSymbolService.cs
@@ -4,7 +4,6 @@
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.FindSymbols;
-using Microsoft.CodeAnalysis.Host;
 using Microsoft.CodeAnalysis.Text;
 
 namespace Microsoft.CodeAnalysis.Editor.GoToDefinition
diff --git a/src/EditorFeatures/Core/GoToDefinition/IGoToDefinitionService.cs b/src/EditorFeatures/Core/GoToDefinition/IGoToDefinitionService.cs
index 2afa5b41f2f73..a8fda42a08a4b 100644
--- a/src/EditorFeatures/Core/GoToDefinition/IGoToDefinitionService.cs
+++ b/src/EditorFeatures/Core/GoToDefinition/IGoToDefinitionService.cs
@@ -5,7 +5,6 @@
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.Host;
 using Microsoft.CodeAnalysis.Navigation;
-using Microsoft.CodeAnalysis.Options;
 
 namespace Microsoft.CodeAnalysis.Editor
 {
diff --git a/src/EditorFeatures/Core/GoToDefinition/IGoToSymbolService.cs b/src/EditorFeatures/Core/GoToDefinition/IGoToSymbolService.cs
index 59b5e560f7102..1572c2b66f677 100644
--- a/src/EditorFeatures/Core/GoToDefinition/IGoToSymbolService.cs
+++ b/src/EditorFeatures/Core/GoToDefinition/IGoToSymbolService.cs
@@ -1,11 +1,5 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
-using System;
-using System.Collections.Generic;
-using System.Collections.Immutable;
-using System.Linq;
-using System.Text;
-using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.Host;
 
diff --git a/src/EditorFeatures/Core/GoToDefinition/WellKnownDefinitionTypes.cs b/src/EditorFeatures/Core/GoToDefinition/WellKnownDefinitionTypes.cs
index 7de843a6cc9b8..7ead90c1d79ef 100644
--- a/src/EditorFeatures/Core/GoToDefinition/WellKnownDefinitionTypes.cs
+++ b/src/EditorFeatures/Core/GoToDefinition/WellKnownDefinitionTypes.cs
@@ -1,6 +1,5 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
-
 namespace Microsoft.CodeAnalysis.Editor.GoToDefinition
 {
     internal class WellKnownDefinitionTypes

From 18e96b0677f5de6006afe03570a2680a82ab289d Mon Sep 17 00:00:00 2001
From: Ravi Chande <rchande@microsoft.com>
Date: Mon, 31 Jul 2017 14:32:51 -0700
Subject: [PATCH 12/77] indenting

---
 .../GoToDefinition/AbstractGoToDefinitionItemService.cs   | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/EditorFeatures/Core/GoToDefinition/AbstractGoToDefinitionItemService.cs b/src/EditorFeatures/Core/GoToDefinition/AbstractGoToDefinitionItemService.cs
index 01d6e66312754..55cade7ec84c7 100644
--- a/src/EditorFeatures/Core/GoToDefinition/AbstractGoToDefinitionItemService.cs
+++ b/src/EditorFeatures/Core/GoToDefinition/AbstractGoToDefinitionItemService.cs
@@ -27,10 +27,10 @@ public async Task GetDefinitionsAsync(GoToDefinitionContext context)
             // XAML, etc. That call has to be done on the UI thread.
             var definitions = await Task.Factory.StartNew(() =>
                 GoToDefinitionHelpers.GetDefinitions(symbol, document.Project, thirdPartyNavigationAllowed: true, cancellationToken: cancellationToken)
-                .WhereAsArray(d => d.CanNavigateTo(document.Project.Solution.Workspace)),
-                cancellationToken,
-                TaskCreationOptions.None,
-                ForegroundTaskScheduler).ConfigureAwait(false);
+                    .WhereAsArray(d => d.CanNavigateTo(document.Project.Solution.Workspace)),
+                        cancellationToken,
+                        TaskCreationOptions.None,
+                        ForegroundTaskScheduler).ConfigureAwait(false);
 
             foreach (var definition in definitions)
             {

From f1ee17306ce43dfe464213050db40589c8e8d0ae Mon Sep 17 00:00:00 2001
From: Ravi Chande <rchande@microsoft.com>
Date: Mon, 31 Jul 2017 14:52:49 -0700
Subject: [PATCH 13/77] Add missing files

---
 .../Test2/EditorServicesTest2.vbproj          |  1 +
 .../Test2/NavigableSymbolsTest.vb             | 73 +++++++++++++++++++
 2 files changed, 74 insertions(+)
 create mode 100644 src/EditorFeatures/Test2/NavigableSymbolsTest.vb

diff --git a/src/EditorFeatures/Test2/EditorServicesTest2.vbproj b/src/EditorFeatures/Test2/EditorServicesTest2.vbproj
index d6707e52f89c5..d5201c76b68c5 100644
--- a/src/EditorFeatures/Test2/EditorServicesTest2.vbproj
+++ b/src/EditorFeatures/Test2/EditorServicesTest2.vbproj
@@ -249,6 +249,7 @@
     <Compile Include="IntelliSense\CompletionRulesTests.vb" />
     <Compile Include="LanguageServices\SyntaxFactsServiceTests.vb" />
     <Compile Include="NamingStyles\NamingStylesTests.vb" />
+    <Compile Include="NavigableSymbols\NavigableSymbolsTest.vb" />
     <Compile Include="ReferenceHighlighting\DocumentHighlightsServiceTests.vb" />
     <Compile Include="Simplification\BlockSimplificationTests.vb" />
     <Compile Include="Simplification\SimplifierAPITests.vb" />
diff --git a/src/EditorFeatures/Test2/NavigableSymbolsTest.vb b/src/EditorFeatures/Test2/NavigableSymbolsTest.vb
new file mode 100644
index 0000000000000..5c3d2ecaee323
--- /dev/null
+++ b/src/EditorFeatures/Test2/NavigableSymbolsTest.vb
@@ -0,0 +1,73 @@
+' Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+Imports System
+Imports System.Linq
+Imports System.Threading
+Imports System.Threading.Tasks
+Imports Microsoft.CodeAnalysis.Editor.Host
+Imports Microsoft.CodeAnalysis.Editor.NavigableSymbols
+Imports Microsoft.CodeAnalysis.Editor.UnitTests.BraceMatching
+Imports Microsoft.CodeAnalysis.Editor.UnitTests.Utilities
+Imports Microsoft.CodeAnalysis.Editor.UnitTests.Utilities.GoToHelpers
+Imports Microsoft.CodeAnalysis.Editor.UnitTests.Workspaces
+Imports Microsoft.CodeAnalysis.Navigation
+Imports Microsoft.VisualStudio.Composition
+Imports Microsoft.VisualStudio.Text
+Imports Roslyn.Test.Utilities
+Imports Xunit
+
+Namespace Microsoft.CodeAnalysis.Editor.UnitTests.NavigableSymbols
+
+    Public Class NavigableSymbolsTest
+
+        Private Shared ReadOnly s_exportProvider As ExportProvider = MinimalTestExportProvider.CreateExportProvider(
+            TestExportProvider.EntireAssemblyCatalogWithCSharpAndVisualBasic.WithParts(
+                GetType(MockDocumentNavigationServiceProvider),
+                GetType(MockSymbolNavigationServiceProvider)))
+
+        <WpfFact>
+        Public Async Function TestCharp() As Task
+            Using workspace = TestWorkspace.CreateCSharp("
+class C
+{
+    C$$ c
+}", exportProvider:=s_exportProvider)
+
+
+                Await TestNavigated(workspace)
+            End Using
+        End Function
+
+        <WpfFact>
+        Public Async Function TestVB() As Task
+            Using workspace = TestWorkspace.CreateVisualBasic("
+Class C
+    Dim c as C$$
+End Class", exportProvider:=s_exportProvider)
+
+
+                Await TestNavigated(workspace)
+            End Using
+        End Function
+
+        Private Async Function TestNavigated(workspace As TestWorkspace) As Task
+
+            Dim presenter = {New Lazy(Of IStreamingFindUsagesPresenter)(Function() New MockStreamingFindUsagesPresenter(Sub() Return))}
+            Dim service = New NavigableSymbolService(TestWaitIndicator.Default, presenter)
+            Dim view = workspace.Documents.First().GetTextView()
+            Dim Buffer = workspace.Documents.First().GetTextBuffer()
+            Dim caretPosition = view.Caret.Position.BufferPosition.Position
+            Dim Span = New SnapshotSpan(Buffer.CurrentSnapshot, New Span(caretPosition, 0))
+            Dim source = service.TryCreateNavigableSymbolSource(view, Buffer)
+            Dim symbol = Await source.GetNavigableSymbolAsync(Span, CancellationToken.None)
+
+            Assert.NotNull(symbol)
+            symbol.Navigate(symbol.Relationships.First())
+
+            Dim navigationService = DirectCast(workspace.Services.GetService(Of IDocumentNavigationService)(), MockDocumentNavigationServiceProvider.MockDocumentNavigationService)
+            Assert.Equal(True, navigationService.TryNavigateToLineAndOffsetReturnValue)
+            Assert.Equal(True, navigationService.TryNavigateToPositionReturnValue)
+            Assert.Equal(True, navigationService.TryNavigateToSpanReturnValue)
+        End Function
+    End Class
+End Namespace

From 609901ac19d3b47a632f7e2fa537723701258f8f Mon Sep 17 00:00:00 2001
From: Ravi Chande <rchande@microsoft.com>
Date: Mon, 31 Jul 2017 14:52:55 -0700
Subject: [PATCH 14/77] Verify span

---
 .../NavigableSymbols/NavigableSymbolsTest.vb  | 41 +++++++++++--------
 1 file changed, 25 insertions(+), 16 deletions(-)

diff --git a/src/EditorFeatures/Test2/NavigableSymbols/NavigableSymbolsTest.vb b/src/EditorFeatures/Test2/NavigableSymbols/NavigableSymbolsTest.vb
index 5c3d2ecaee323..7fbb81834fdb4 100644
--- a/src/EditorFeatures/Test2/NavigableSymbols/NavigableSymbolsTest.vb
+++ b/src/EditorFeatures/Test2/NavigableSymbols/NavigableSymbolsTest.vb
@@ -4,6 +4,7 @@ Imports System
 Imports System.Linq
 Imports System.Threading
 Imports System.Threading.Tasks
+Imports Microsoft.CodeAnalysis.Text
 Imports Microsoft.CodeAnalysis.Editor.Host
 Imports Microsoft.CodeAnalysis.Editor.NavigableSymbols
 Imports Microsoft.CodeAnalysis.Editor.UnitTests.BraceMatching
@@ -27,39 +28,46 @@ Namespace Microsoft.CodeAnalysis.Editor.UnitTests.NavigableSymbols
 
         <WpfFact>
         Public Async Function TestCharp() As Task
-            Using workspace = TestWorkspace.CreateCSharp("
-class C
+            Dim markup = "
+class [|C|]
 {
     C$$ c
-}", exportProvider:=s_exportProvider)
+}"
+            Dim text As String = Nothing
+            Dim position As Integer
+            Dim span As TextSpan
+            MarkupTestFile.GetPositionAndSpan(markup, text, position, span)
 
-
-                Await TestNavigated(workspace)
+            Using workspace = TestWorkspace.CreateCSharp(text, exportProvider:=s_exportProvider)
+                Await TestNavigated(workspace, position, span)
             End Using
         End Function
 
         <WpfFact>
         Public Async Function TestVB() As Task
-            Using workspace = TestWorkspace.CreateVisualBasic("
-Class C
+            Dim markup = "
+Class [|C|]
     Dim c as C$$
-End Class", exportProvider:=s_exportProvider)
-
+End Class"
+            Dim text As String = Nothing
+            Dim position As Integer
+            Dim span As TextSpan
+            MarkupTestFile.GetPositionAndSpan(markup, text, position, span)
 
-                Await TestNavigated(workspace)
+            Using workspace = TestWorkspace.CreateVisualBasic(text, exportProvider:=s_exportProvider)
+                Await TestNavigated(workspace, position, span)
             End Using
         End Function
 
-        Private Async Function TestNavigated(workspace As TestWorkspace) As Task
+        Private Async Function TestNavigated(workspace As TestWorkspace, position As Integer, span As TextSpan) As Task
 
             Dim presenter = {New Lazy(Of IStreamingFindUsagesPresenter)(Function() New MockStreamingFindUsagesPresenter(Sub() Return))}
             Dim service = New NavigableSymbolService(TestWaitIndicator.Default, presenter)
             Dim view = workspace.Documents.First().GetTextView()
-            Dim Buffer = workspace.Documents.First().GetTextBuffer()
-            Dim caretPosition = view.Caret.Position.BufferPosition.Position
-            Dim Span = New SnapshotSpan(Buffer.CurrentSnapshot, New Span(caretPosition, 0))
-            Dim source = service.TryCreateNavigableSymbolSource(view, Buffer)
-            Dim symbol = Await source.GetNavigableSymbolAsync(Span, CancellationToken.None)
+            Dim buffer = workspace.Documents.First().GetTextBuffer()
+            Dim triggerSpan = New SnapshotSpan(buffer.CurrentSnapshot, New Span(position, 0))
+            Dim source = service.TryCreateNavigableSymbolSource(view, buffer)
+            Dim symbol = Await source.GetNavigableSymbolAsync(triggerSpan, CancellationToken.None)
 
             Assert.NotNull(symbol)
             symbol.Navigate(symbol.Relationships.First())
@@ -68,6 +76,7 @@ End Class", exportProvider:=s_exportProvider)
             Assert.Equal(True, navigationService.TryNavigateToLineAndOffsetReturnValue)
             Assert.Equal(True, navigationService.TryNavigateToPositionReturnValue)
             Assert.Equal(True, navigationService.TryNavigateToSpanReturnValue)
+            Assert.Equal(span, navigationService.ProvidedTextSpan)
         End Function
     End Class
 End Namespace

From 30cc09b122ef862ac915e115b1db1dbffd1d84a7 Mon Sep 17 00:00:00 2001
From: Ravi Chande <rchande@microsoft.com>
Date: Mon, 31 Jul 2017 14:56:35 -0700
Subject: [PATCH 15/77] whitespace

---
 .../Test2/NavigableSymbols/NavigableSymbolsTest.vb               | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/EditorFeatures/Test2/NavigableSymbols/NavigableSymbolsTest.vb b/src/EditorFeatures/Test2/NavigableSymbols/NavigableSymbolsTest.vb
index 7fbb81834fdb4..c7f04bc50768e 100644
--- a/src/EditorFeatures/Test2/NavigableSymbols/NavigableSymbolsTest.vb
+++ b/src/EditorFeatures/Test2/NavigableSymbols/NavigableSymbolsTest.vb
@@ -60,7 +60,6 @@ End Class"
         End Function
 
         Private Async Function TestNavigated(workspace As TestWorkspace, position As Integer, span As TextSpan) As Task
-
             Dim presenter = {New Lazy(Of IStreamingFindUsagesPresenter)(Function() New MockStreamingFindUsagesPresenter(Sub() Return))}
             Dim service = New NavigableSymbolService(TestWaitIndicator.Default, presenter)
             Dim view = workspace.Documents.First().GetTextView()

From c9831d7de38fa589788b08d188abd19637c21ba6 Mon Sep 17 00:00:00 2001
From: Ravi Chande <rchande@microsoft.com>
Date: Tue, 1 Aug 2017 08:28:12 -0700
Subject: [PATCH 16/77] Test both spans

---
 .../NavigableSymbols/NavigableSymbolsTest.vb  | 35 +++++++++++--------
 1 file changed, 21 insertions(+), 14 deletions(-)

diff --git a/src/EditorFeatures/Test2/NavigableSymbols/NavigableSymbolsTest.vb b/src/EditorFeatures/Test2/NavigableSymbols/NavigableSymbolsTest.vb
index c7f04bc50768e..2f9ebf538152b 100644
--- a/src/EditorFeatures/Test2/NavigableSymbols/NavigableSymbolsTest.vb
+++ b/src/EditorFeatures/Test2/NavigableSymbols/NavigableSymbolsTest.vb
@@ -2,9 +2,11 @@
 
 Imports System
 Imports System.Linq
+Imports System.Collections.Immutable
 Imports System.Threading
 Imports System.Threading.Tasks
 Imports Microsoft.CodeAnalysis.Text
+Imports Microsoft.CodeAnalysis.Text.Shared.Extensions
 Imports Microsoft.CodeAnalysis.Editor.Host
 Imports Microsoft.CodeAnalysis.Editor.NavigableSymbols
 Imports Microsoft.CodeAnalysis.Editor.UnitTests.BraceMatching
@@ -29,37 +31,37 @@ Namespace Microsoft.CodeAnalysis.Editor.UnitTests.NavigableSymbols
         <WpfFact>
         Public Async Function TestCharp() As Task
             Dim markup = "
-class [|C|]
+class {|target:C|}
 {
-    C$$ c
+    {|highlighted:C|}$$ c
 }"
             Dim text As String = Nothing
-            Dim position As Integer
-            Dim span As TextSpan
-            MarkupTestFile.GetPositionAndSpan(markup, text, position, span)
+            Dim position As Integer? = Nothing
+            Dim spans As IDictionary(Of String, ImmutableArray(Of TextSpan)) = Nothing
+            MarkupTestFile.GetPositionAndSpans(markup, text, position, spans)
 
             Using workspace = TestWorkspace.CreateCSharp(text, exportProvider:=s_exportProvider)
-                Await TestNavigated(workspace, position, span)
+                Await TestNavigated(workspace, position.Value, spans)
             End Using
         End Function
 
         <WpfFact>
         Public Async Function TestVB() As Task
             Dim markup = "
-Class [|C|]
-    Dim c as C$$
+Class {|target:C|}
+    Dim c as {|highlighted:C|}$$
 End Class"
             Dim text As String = Nothing
-            Dim position As Integer
-            Dim span As TextSpan
-            MarkupTestFile.GetPositionAndSpan(markup, text, position, span)
+            Dim position As Integer? = Nothing
+            Dim spans As IDictionary(Of String, ImmutableArray(Of TextSpan)) = Nothing
+            MarkupTestFile.GetPositionAndSpans(markup, text, position, spans)
 
             Using workspace = TestWorkspace.CreateVisualBasic(text, exportProvider:=s_exportProvider)
-                Await TestNavigated(workspace, position, span)
+                Await TestNavigated(workspace, position.Value, spans)
             End Using
         End Function
 
-        Private Async Function TestNavigated(workspace As TestWorkspace, position As Integer, span As TextSpan) As Task
+        Private Async Function TestNavigated(workspace As TestWorkspace, position As Integer, spans As IDictionary(Of String, ImmutableArray(Of TextSpan))) As Task
             Dim presenter = {New Lazy(Of IStreamingFindUsagesPresenter)(Function() New MockStreamingFindUsagesPresenter(Sub() Return))}
             Dim service = New NavigableSymbolService(TestWaitIndicator.Default, presenter)
             Dim view = workspace.Documents.First().GetTextView()
@@ -68,14 +70,19 @@ End Class"
             Dim source = service.TryCreateNavigableSymbolSource(view, buffer)
             Dim symbol = Await source.GetNavigableSymbolAsync(triggerSpan, CancellationToken.None)
 
+            Dim highlightedSpan = spans("highlighted").First()
+            Dim navigationTarget = spans("target").First()
+
             Assert.NotNull(symbol)
+            Assert.Equal(highlightedSpan.ToSpan(), symbol.SymbolSpan.Span)
+
             symbol.Navigate(symbol.Relationships.First())
 
             Dim navigationService = DirectCast(workspace.Services.GetService(Of IDocumentNavigationService)(), MockDocumentNavigationServiceProvider.MockDocumentNavigationService)
             Assert.Equal(True, navigationService.TryNavigateToLineAndOffsetReturnValue)
             Assert.Equal(True, navigationService.TryNavigateToPositionReturnValue)
             Assert.Equal(True, navigationService.TryNavigateToSpanReturnValue)
-            Assert.Equal(span, navigationService.ProvidedTextSpan)
+            Assert.Equal(navigationTarget, navigationService.ProvidedTextSpan)
         End Function
     End Class
 End Namespace

From ba4fce00df9843007480008f2e91a8b08038c03c Mon Sep 17 00:00:00 2001
From: Ravi Chande <rchande@microsoft.com>
Date: Tue, 1 Aug 2017 08:28:38 -0700
Subject: [PATCH 17/77] Remove unused property:

---
 src/EditorFeatures/Core/GoToDefinition/GoToDefinitionContext.cs | 1 -
 1 file changed, 1 deletion(-)

diff --git a/src/EditorFeatures/Core/GoToDefinition/GoToDefinitionContext.cs b/src/EditorFeatures/Core/GoToDefinition/GoToDefinitionContext.cs
index f27b2323c5e4d..b057d8319f16b 100644
--- a/src/EditorFeatures/Core/GoToDefinition/GoToDefinitionContext.cs
+++ b/src/EditorFeatures/Core/GoToDefinition/GoToDefinitionContext.cs
@@ -25,7 +25,6 @@ public GoToDefinitionContext(Document document, int position, CancellationToken
         public int Position { get; }
         public CancellationToken CancellationToken { get; }
 
-        public IReadOnlyDictionary<string, List<DefinitionItem>> Items => null;// _items;
         public TextSpan Span { get; set; }
 
         public bool TryGetItems(string key, out IEnumerable<DefinitionItem> items)

From ba23e854c777f90f3258dad057f9a3e9a6dac31e Mon Sep 17 00:00:00 2001
From: Ravi Chande <rchande@microsoft.com>
Date: Tue, 1 Aug 2017 08:58:13 -0700
Subject: [PATCH 18/77] Properly check for no value

---
 .../Core/GoToDefinition/GoToDefinitionContext.cs   | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/src/EditorFeatures/Core/GoToDefinition/GoToDefinitionContext.cs b/src/EditorFeatures/Core/GoToDefinition/GoToDefinitionContext.cs
index b057d8319f16b..73963054714d9 100644
--- a/src/EditorFeatures/Core/GoToDefinition/GoToDefinitionContext.cs
+++ b/src/EditorFeatures/Core/GoToDefinition/GoToDefinitionContext.cs
@@ -29,8 +29,18 @@ public GoToDefinitionContext(Document document, int position, CancellationToken
 
         public bool TryGetItems(string key, out IEnumerable<DefinitionItem> items)
         {
-            items = _items[key];
-            return items != null;
+            if (_items.ContainsKey(key))
+            {
+                // Multidictionary valuesets are structs so we can't
+                // just check for null
+                items = _items[key];
+                return true;
+            }
+            else
+            {
+                items = null;
+                return false;
+            }
         }
 
         public void AddItem(string key, DefinitionItem item)

From e08beed0bf91ad0b1216f821bd35f9a16188a307 Mon Sep 17 00:00:00 2001
From: Ravi Chande <rchande@microsoft.com>
Date: Tue, 1 Aug 2017 12:50:42 -0700
Subject: [PATCH 19/77] Make names more consistent

---
 ...oDefinitionItemService.cs => CSharpGoToSymbolService.cs} | 2 +-
 ...efinitionItemService.cs => AbstractGoToSymbolService.cs} | 6 +++---
 .../{GoToDefinitionContext.cs => GoToSymbolContext.cs}      | 6 +++---
 .../Core/GoToDefinition/IGoToSymbolService.cs               | 2 +-
 ...{WellKnownDefinitionTypes.cs => WellKnownSymbolTypes.cs} | 2 +-
 .../NavigableSymbolService.NavigableSymbolSource.cs         | 4 ++--
 src/EditorFeatures/TestUtilities/Traits.cs                  | 1 +
 ...nitionItemService.vb => VisualBasicGoToSymbolService.vb} | 4 ++--
 8 files changed, 14 insertions(+), 13 deletions(-)
 rename src/EditorFeatures/CSharp/GoToDefinition/{CSharpGoToDefinitionItemService.cs => CSharpGoToSymbolService.cs} (82%)
 rename src/EditorFeatures/Core/GoToDefinition/{AbstractGoToDefinitionItemService.cs => AbstractGoToSymbolService.cs} (85%)
 rename src/EditorFeatures/Core/GoToDefinition/{GoToDefinitionContext.cs => GoToSymbolContext.cs} (86%)
 rename src/EditorFeatures/Core/GoToDefinition/{WellKnownDefinitionTypes.cs => WellKnownSymbolTypes.cs} (87%)
 rename src/EditorFeatures/VisualBasic/GoToDefinition/{VisualBasicGoToDefinitionItemService.vb => VisualBasicGoToSymbolService.vb} (74%)

diff --git a/src/EditorFeatures/CSharp/GoToDefinition/CSharpGoToDefinitionItemService.cs b/src/EditorFeatures/CSharp/GoToDefinition/CSharpGoToSymbolService.cs
similarity index 82%
rename from src/EditorFeatures/CSharp/GoToDefinition/CSharpGoToDefinitionItemService.cs
rename to src/EditorFeatures/CSharp/GoToDefinition/CSharpGoToSymbolService.cs
index 40548e25f498d..dad65c608e34a 100644
--- a/src/EditorFeatures/CSharp/GoToDefinition/CSharpGoToDefinitionItemService.cs
+++ b/src/EditorFeatures/CSharp/GoToDefinition/CSharpGoToSymbolService.cs
@@ -10,7 +10,7 @@
 namespace Microsoft.CodeAnalysis.Editor.CSharp.GoToDefinition
 {
     [ExportLanguageService(typeof(IGoToSymbolService), LanguageNames.CSharp), Shared]
-    internal class CSharpGoToDefinitionItemService : AbstractGoToDefinitionItemService
+    internal class CSharpGoToSymbolService : AbstractGoToSymbolService
     {
     }
 }
diff --git a/src/EditorFeatures/Core/GoToDefinition/AbstractGoToDefinitionItemService.cs b/src/EditorFeatures/Core/GoToDefinition/AbstractGoToSymbolService.cs
similarity index 85%
rename from src/EditorFeatures/Core/GoToDefinition/AbstractGoToDefinitionItemService.cs
rename to src/EditorFeatures/Core/GoToDefinition/AbstractGoToSymbolService.cs
index 55cade7ec84c7..e2b79171e242a 100644
--- a/src/EditorFeatures/Core/GoToDefinition/AbstractGoToDefinitionItemService.cs
+++ b/src/EditorFeatures/Core/GoToDefinition/AbstractGoToSymbolService.cs
@@ -6,9 +6,9 @@
 
 namespace Microsoft.CodeAnalysis.Editor.GoToDefinition
 {
-    internal abstract class AbstractGoToDefinitionItemService : ForegroundThreadAffinitizedObject, IGoToSymbolService
+    internal abstract class AbstractGoToSymbolService : ForegroundThreadAffinitizedObject, IGoToSymbolService
     {
-        public async Task GetDefinitionsAsync(GoToDefinitionContext context)
+        public async Task GetDefinitionsAsync(GoToSymbolContext context)
         {
             var document = context.Document;
             var position = context.Position;
@@ -34,7 +34,7 @@ public async Task GetDefinitionsAsync(GoToDefinitionContext context)
 
             foreach (var definition in definitions)
             {
-                context.AddItem(WellKnownDefinitionTypes.Definition, definition);
+                context.AddItem(WellKnownSymbolTypes.Definition, definition);
             }
 
             context.Span = span;
diff --git a/src/EditorFeatures/Core/GoToDefinition/GoToDefinitionContext.cs b/src/EditorFeatures/Core/GoToDefinition/GoToSymbolContext.cs
similarity index 86%
rename from src/EditorFeatures/Core/GoToDefinition/GoToDefinitionContext.cs
rename to src/EditorFeatures/Core/GoToDefinition/GoToSymbolContext.cs
index 73963054714d9..9703951cf4441 100644
--- a/src/EditorFeatures/Core/GoToDefinition/GoToDefinitionContext.cs
+++ b/src/EditorFeatures/Core/GoToDefinition/GoToSymbolContext.cs
@@ -8,13 +8,13 @@
 
 namespace Microsoft.CodeAnalysis.Editor.GoToDefinition
 {
-    internal class GoToDefinitionContext
+    internal class GoToSymbolContext
     {
         private readonly object _gate = new object();
 
         private readonly MultiDictionary<string, DefinitionItem> _items = new MultiDictionary<string, DefinitionItem>();
 
-        public GoToDefinitionContext(Document document, int position, CancellationToken cancellationToken)
+        public GoToSymbolContext(Document document, int position, CancellationToken cancellationToken)
         {
             Document = document;
             Position = position;
@@ -27,7 +27,7 @@ public GoToDefinitionContext(Document document, int position, CancellationToken
 
         public TextSpan Span { get; set; }
 
-        public bool TryGetItems(string key, out IEnumerable<DefinitionItem> items)
+        internal bool TryGetItems(string key, out IEnumerable<DefinitionItem> items)
         {
             if (_items.ContainsKey(key))
             {
diff --git a/src/EditorFeatures/Core/GoToDefinition/IGoToSymbolService.cs b/src/EditorFeatures/Core/GoToDefinition/IGoToSymbolService.cs
index 1572c2b66f677..f95f587ec4d0e 100644
--- a/src/EditorFeatures/Core/GoToDefinition/IGoToSymbolService.cs
+++ b/src/EditorFeatures/Core/GoToDefinition/IGoToSymbolService.cs
@@ -7,6 +7,6 @@ namespace Microsoft.CodeAnalysis.Editor.GoToDefinition
 {
     internal interface IGoToSymbolService : ILanguageService
     {
-        Task GetDefinitionsAsync(GoToDefinitionContext context);
+        Task GetDefinitionsAsync(GoToSymbolContext context);
     }
 }
diff --git a/src/EditorFeatures/Core/GoToDefinition/WellKnownDefinitionTypes.cs b/src/EditorFeatures/Core/GoToDefinition/WellKnownSymbolTypes.cs
similarity index 87%
rename from src/EditorFeatures/Core/GoToDefinition/WellKnownDefinitionTypes.cs
rename to src/EditorFeatures/Core/GoToDefinition/WellKnownSymbolTypes.cs
index 7ead90c1d79ef..b50ea7f313c72 100644
--- a/src/EditorFeatures/Core/GoToDefinition/WellKnownDefinitionTypes.cs
+++ b/src/EditorFeatures/Core/GoToDefinition/WellKnownSymbolTypes.cs
@@ -2,7 +2,7 @@
 
 namespace Microsoft.CodeAnalysis.Editor.GoToDefinition
 {
-    internal class WellKnownDefinitionTypes
+    internal class WellKnownSymbolTypes
     {
         public const string Definition = nameof(Definition);
     }
diff --git a/src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.NavigableSymbolSource.cs b/src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.NavigableSymbolSource.cs
index 2211beabe5c9e..da5ecfaed1db9 100644
--- a/src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.NavigableSymbolSource.cs
+++ b/src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.NavigableSymbolSource.cs
@@ -56,11 +56,11 @@ public async Task<INavigableSymbol> GetNavigableSymbolAsync(SnapshotSpan trigger
 
                 var service = document.GetLanguageService<IGoToSymbolService>();
 
-                var context = new GoToDefinitionContext(document, position, cancellationToken);
+                var context = new GoToSymbolContext(document, position, cancellationToken);
 
                 await service.GetDefinitionsAsync(context).ConfigureAwait(false);
 
-                if (!context.TryGetItems(WellKnownDefinitionTypes.Definition, out var definitions))
+                if (!context.TryGetItems(WellKnownSymbolTypes.Definition, out var definitions))
                 {
                     return null;
                 }
diff --git a/src/EditorFeatures/TestUtilities/Traits.cs b/src/EditorFeatures/TestUtilities/Traits.cs
index da4c5cab9b3be..ab750f309abd3 100644
--- a/src/EditorFeatures/TestUtilities/Traits.cs
+++ b/src/EditorFeatures/TestUtilities/Traits.cs
@@ -144,6 +144,7 @@ public static class Features
             public const string LineSeparators = nameof(LineSeparators);
             public const string MetadataAsSource = nameof(MetadataAsSource);
             public const string NamingStyle = nameof(NamingStyle);
+            public const string NavigableSymbols = nameof(NavigableSymbols);
             public const string NavigateTo = nameof(NavigateTo);
             public const string NavigationBar = nameof(NavigationBar);
             public const string ObjectBrowser = nameof(ObjectBrowser);
diff --git a/src/EditorFeatures/VisualBasic/GoToDefinition/VisualBasicGoToDefinitionItemService.vb b/src/EditorFeatures/VisualBasic/GoToDefinition/VisualBasicGoToSymbolService.vb
similarity index 74%
rename from src/EditorFeatures/VisualBasic/GoToDefinition/VisualBasicGoToDefinitionItemService.vb
rename to src/EditorFeatures/VisualBasic/GoToDefinition/VisualBasicGoToSymbolService.vb
index df953bf33714d..63f61a14af8f9 100644
--- a/src/EditorFeatures/VisualBasic/GoToDefinition/VisualBasicGoToDefinitionItemService.vb
+++ b/src/EditorFeatures/VisualBasic/GoToDefinition/VisualBasicGoToSymbolService.vb
@@ -4,8 +4,8 @@ Imports Microsoft.CodeAnalysis.Host.Mef
 
 Namespace Microsoft.CodeAnalysis.Editor.VisualBasic.GoToDefinition
     <ExportLanguageService(GetType(IGoToSymbolService), LanguageNames.VisualBasic), [Shared]>
-    Friend Class VisualBasicGoToDefinitionItemService
-        Inherits AbstractGoToDefinitionItemService
+    Friend Class VisualBasicGoToSymbolService
+        Inherits AbstractGoToSymbolService
 
     End Class
 End Namespace

From 7f1c153a64fd33d874f27908f3e1baec4b6a529b Mon Sep 17 00:00:00 2001
From: Ravi Chande <rchande@microsoft.com>
Date: Tue, 1 Aug 2017 12:52:15 -0700
Subject: [PATCH 20/77] Add Traits

---
 .../Test2/NavigableSymbols/NavigableSymbolsTest.vb            | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/EditorFeatures/Test2/NavigableSymbols/NavigableSymbolsTest.vb b/src/EditorFeatures/Test2/NavigableSymbols/NavigableSymbolsTest.vb
index 2f9ebf538152b..38414782967c9 100644
--- a/src/EditorFeatures/Test2/NavigableSymbols/NavigableSymbolsTest.vb
+++ b/src/EditorFeatures/Test2/NavigableSymbols/NavigableSymbolsTest.vb
@@ -28,7 +28,7 @@ Namespace Microsoft.CodeAnalysis.Editor.UnitTests.NavigableSymbols
                 GetType(MockDocumentNavigationServiceProvider),
                 GetType(MockSymbolNavigationServiceProvider)))
 
-        <WpfFact>
+        <WpfFact, Trait(Traits.Feature, Traits.Features.NavigableSymbols)>
         Public Async Function TestCharp() As Task
             Dim markup = "
 class {|target:C|}
@@ -45,7 +45,7 @@ class {|target:C|}
             End Using
         End Function
 
-        <WpfFact>
+        <WpfFact, Trait(Traits.Feature, Traits.Features.NavigableSymbols)>
         Public Async Function TestVB() As Task
             Dim markup = "
 Class {|target:C|}

From 76f8f9fe59d6401e5bbc1dd6188e6a29e53f567b Mon Sep 17 00:00:00 2001
From: Ravi Chande <rchande@microsoft.com>
Date: Tue, 1 Aug 2017 13:04:46 -0700
Subject: [PATCH 21/77] Update another name; add project files

---
 src/EditorFeatures/CSharp/CSharpEditorFeatures.csproj       | 2 +-
 src/EditorFeatures/Core/EditorFeatures.csproj               | 6 +++---
 .../Core/GoToDefinition/AbstractGoToSymbolService.cs        | 2 +-
 .../Core/GoToDefinition/IGoToSymbolService.cs               | 2 +-
 .../NavigableSymbolService.NavigableSymbolSource.cs         | 2 +-
 src/EditorFeatures/VisualBasic/BasicEditorFeatures.vbproj   | 2 +-
 6 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/src/EditorFeatures/CSharp/CSharpEditorFeatures.csproj b/src/EditorFeatures/CSharp/CSharpEditorFeatures.csproj
index eebe79e1fb799..52b444bc3b151 100644
--- a/src/EditorFeatures/CSharp/CSharpEditorFeatures.csproj
+++ b/src/EditorFeatures/CSharp/CSharpEditorFeatures.csproj
@@ -116,7 +116,7 @@
     <Compile Include="Formatting\Indentation\SmartTokenFormatterCommandHandler.cs" />
     <Compile Include="Formatting\Indentation\WhitespaceExtensions.cs" />
     <Compile Include="Formatting\CSharpEditorFormattingService.PasteFormattingRule.cs" />
-    <Compile Include="GoToDefinition\CSharpGoToDefinitionItemService.cs" />
+    <Compile Include="GoToDefinition\CSharpGoToSymbolService.cs" />
     <Compile Include="GoToDefinition\CSharpGoToDefinitionService.cs" />
     <Compile Include="GoToDefinition\CSharpGoToDefinitionSymbolService.cs" />
     <Compile Include="Highlighting\KeywordHighlighters\AbstractAsyncHighlighter.cs" />
diff --git a/src/EditorFeatures/Core/EditorFeatures.csproj b/src/EditorFeatures/Core/EditorFeatures.csproj
index 05b3a8c7f84f5..dc4b3b5e2cbdb 100644
--- a/src/EditorFeatures/Core/EditorFeatures.csproj
+++ b/src/EditorFeatures/Core/EditorFeatures.csproj
@@ -161,12 +161,12 @@
     <Compile Include="FindUsages\IFindUsagesContext.cs" />
     <Compile Include="FindUsages\IFindUsagesService.cs" />
     <Compile Include="FindUsages\SimpleFindUsagesContext.cs" />
-    <Compile Include="GoToDefinition\AbstractGoToDefinitionItemService.cs" />
+    <Compile Include="GoToDefinition\AbstractGoToSymbolService.cs" />
     <Compile Include="GoToDefinition\AbstractGoToDefinitionSymbolService.cs" />
-    <Compile Include="GoToDefinition\GoToDefinitionContext.cs" />
+    <Compile Include="GoToDefinition\GoToSymbolContext.cs" />
     <Compile Include="GoToDefinition\IGoToDefinitionSymbolService.cs" />
     <Compile Include="GoToDefinition\IGoToSymbolService.cs" />
-    <Compile Include="GoToDefinition\WellKnownDefinitionTypes.cs" />
+    <Compile Include="GoToDefinition\WellKnownSymbolTypes.cs" />
     <Compile Include="Implementation\InlineRename\Dashboard\DashboardAutomationPeer.cs" />
     <Compile Include="Implementation\InlineRename\HighlightTags\RenameConflictTag.cs" />
     <Compile Include="Implementation\InlineRename\HighlightTags\RenameConflictTagDefinition.cs" />
diff --git a/src/EditorFeatures/Core/GoToDefinition/AbstractGoToSymbolService.cs b/src/EditorFeatures/Core/GoToDefinition/AbstractGoToSymbolService.cs
index e2b79171e242a..4e0488a7485bc 100644
--- a/src/EditorFeatures/Core/GoToDefinition/AbstractGoToSymbolService.cs
+++ b/src/EditorFeatures/Core/GoToDefinition/AbstractGoToSymbolService.cs
@@ -8,7 +8,7 @@ namespace Microsoft.CodeAnalysis.Editor.GoToDefinition
 {
     internal abstract class AbstractGoToSymbolService : ForegroundThreadAffinitizedObject, IGoToSymbolService
     {
-        public async Task GetDefinitionsAsync(GoToSymbolContext context)
+        public async Task GetSymbolsAsync(GoToSymbolContext context)
         {
             var document = context.Document;
             var position = context.Position;
diff --git a/src/EditorFeatures/Core/GoToDefinition/IGoToSymbolService.cs b/src/EditorFeatures/Core/GoToDefinition/IGoToSymbolService.cs
index f95f587ec4d0e..5fa0496599fd2 100644
--- a/src/EditorFeatures/Core/GoToDefinition/IGoToSymbolService.cs
+++ b/src/EditorFeatures/Core/GoToDefinition/IGoToSymbolService.cs
@@ -7,6 +7,6 @@ namespace Microsoft.CodeAnalysis.Editor.GoToDefinition
 {
     internal interface IGoToSymbolService : ILanguageService
     {
-        Task GetDefinitionsAsync(GoToSymbolContext context);
+        Task GetSymbolsAsync(GoToSymbolContext context);
     }
 }
diff --git a/src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.NavigableSymbolSource.cs b/src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.NavigableSymbolSource.cs
index da5ecfaed1db9..156af97e01a07 100644
--- a/src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.NavigableSymbolSource.cs
+++ b/src/EditorFeatures/Core/NavigableSymbols/NavigableSymbolService.NavigableSymbolSource.cs
@@ -58,7 +58,7 @@ public async Task<INavigableSymbol> GetNavigableSymbolAsync(SnapshotSpan trigger
 
                 var context = new GoToSymbolContext(document, position, cancellationToken);
 
-                await service.GetDefinitionsAsync(context).ConfigureAwait(false);
+                await service.GetSymbolsAsync(context).ConfigureAwait(false);
 
                 if (!context.TryGetItems(WellKnownSymbolTypes.Definition, out var definitions))
                 {
diff --git a/src/EditorFeatures/VisualBasic/BasicEditorFeatures.vbproj b/src/EditorFeatures/VisualBasic/BasicEditorFeatures.vbproj
index 9f4e8c1ec3290..2927451cc1591 100644
--- a/src/EditorFeatures/VisualBasic/BasicEditorFeatures.vbproj
+++ b/src/EditorFeatures/VisualBasic/BasicEditorFeatures.vbproj
@@ -97,7 +97,7 @@
     <Compile Include="Formatting\Indentation\SpecialFormattingOperation.vb" />
     <Compile Include="Formatting\Indentation\VisualBasicIndentationService.Indenter.vb" />
     <Compile Include="Formatting\Indentation\VisualBasicIndentationService.vb" />
-    <Compile Include="GoToDefinition\VisualBasicGoToDefinitionItemService.vb" />
+    <Compile Include="GoToDefinition\VisualBasicGoToSymbolService.vb" />
     <Compile Include="GoToDefinition\VisualBasicGoToDefinitionService.vb" />
     <Compile Include="GoToDefinition\VisualBasicGoToDefinitionSymbolService.vb" />
     <Compile Include="Highlighting\KeywordHighlighters\AccessorDeclarationHighlighter.vb" />

From 37dff668eb79ed4a63ccc7af7e933a209308ccde Mon Sep 17 00:00:00 2001
From: Ravi Chande <rchande@microsoft.com>
Date: Wed, 2 Aug 2017 11:04:17 -0700
Subject: [PATCH 22/77] Reference the correct cibuild script

---
 build/scripts/run_perf.ps1 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/build/scripts/run_perf.ps1 b/build/scripts/run_perf.ps1
index 5bca5dcfcabe4..4aa558a7e7f40 100644
--- a/build/scripts/run_perf.ps1
+++ b/build/scripts/run_perf.ps1
@@ -16,7 +16,7 @@ Invoke-WebRequest -Uri http://dotnetci.blob.core.windows.net/roslyn-perf/cpc.zip
 [Reflection.Assembly]::LoadWithPartialName('System.IO.Compression.FileSystem') | Out-Null
 [IO.Compression.ZipFile]::ExtractToDirectory('cpc.zip', $CPCLocation)
 
-./build/scripts/cibuild.ps1 -release -testPerfRun
+./build/scripts/cibuild.cmd -release -testPerfRun
 
 if ( -not $? )
 {

From dc03d7ae8a5363339b7b50e4c282717a571ee575 Mon Sep 17 00:00:00 2001
From: Tom Meschter <tom.meschter@microsoft.com>
Date: Wed, 2 Aug 2017 12:17:03 -0700
Subject: [PATCH 23/77] Eliminate some duplicate code

The `Report(string, Exception)` and `Report(string, Exception, Func<IFaultUtility, int>)`
methods were almost identical. The former now calls the latter and passes in a default
implementation of `Func<IFaultUtility, int>`.
---
 .../Implementation/Watson/WatsonReporter.cs   | 23 ++++++++-----------
 1 file changed, 10 insertions(+), 13 deletions(-)

diff --git a/src/VisualStudio/Core/Def/Implementation/Watson/WatsonReporter.cs b/src/VisualStudio/Core/Def/Implementation/Watson/WatsonReporter.cs
index 550f75ae71cd5..f8fd0a2dbf3fc 100644
--- a/src/VisualStudio/Core/Def/Implementation/Watson/WatsonReporter.cs
+++ b/src/VisualStudio/Core/Def/Implementation/Watson/WatsonReporter.cs
@@ -9,6 +9,12 @@ namespace Microsoft.VisualStudio.LanguageServices.Implementation
 {
     internal class WatsonReporter
     {
+        /// <summary>
+        /// The default callback to pass to <see cref="TelemetrySessionExtensions.PostFault(TelemetrySession, string, string, Exception, Func{IFaultUtility, int})"/>.
+        /// Returning "0" signals that we should send data to Watson; any other value will cancel the Watson report.
+        /// </summary>
+        private static Func<IFaultUtility, int> s_defaultCallback = _ => 0;
+
         /// <summary>
         /// Report Non-Fatal Watson
         /// </summary>
@@ -25,18 +31,7 @@ public static void Report(Exception exception)
         /// <param name="exception">Exception that triggered this non-fatal error</param>
         public static void Report(string description, Exception exception)
         {
-            TelemetryService.DefaultSession.PostFault(
-                eventName: FunctionId.NonFatalWatson.GetEventName(),
-                description: description,
-                exceptionObject: exception,
-                gatherEventDetails: arg =>
-                {
-                    arg.AddProcessDump(System.Diagnostics.Process.GetCurrentProcess().Id);
-
-                    // 0 means send watson, otherwise, cancel watson
-                    // we always send watson since dump itself can have valuable data
-                    return 0;
-                });
+            Report(description, exception, s_defaultCallback);
         }
 
         /// <summary>
@@ -44,7 +39,9 @@ public static void Report(string description, Exception exception)
         /// </summary>
         /// <param name="description">any description you want to save with this watson report</param>
         /// <param name="exception">Exception that triggered this non-fatal error</param>
-        /// <param name="callback">callback to include extra data with the NFW</param>
+        /// <param name="callback">Callback to include extra data with the NFW. Note that we always collect
+        /// a dump of the current process, but this can be used to add further information or files to the
+        /// CAB.</param>
         public static void Report(string description, Exception exception, Func<IFaultUtility, int> callback)
         {
             TelemetryService.DefaultSession.PostFault(

From 27af25a0f6aa762bafad0ffeb9706d3cd6e220b3 Mon Sep 17 00:00:00 2001
From: Tom Meschter <tom.meschter@microsoft.com>
Date: Wed, 2 Aug 2017 12:31:05 -0700
Subject: [PATCH 24/77] Don't report non-fatal errors after OOM

Once we've seen and "handled" an OutOfMemoryException we're very likely to see
more, and likely to see other kinds of exceptions that are a direct result of
the OOM. We don't want to report these as they aren't helpful and obscure
other, unrelated issues when analyzing reports.

Here we stop reporting all non-fatal errors after the first OOM.
---
 .../Implementation/Watson/WatsonReporter.cs   | 20 +++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/src/VisualStudio/Core/Def/Implementation/Watson/WatsonReporter.cs b/src/VisualStudio/Core/Def/Implementation/Watson/WatsonReporter.cs
index f8fd0a2dbf3fc..677ac878c2541 100644
--- a/src/VisualStudio/Core/Def/Implementation/Watson/WatsonReporter.cs
+++ b/src/VisualStudio/Core/Def/Implementation/Watson/WatsonReporter.cs
@@ -15,6 +15,13 @@ internal class WatsonReporter
         /// </summary>
         private static Func<IFaultUtility, int> s_defaultCallback = _ => 0;
 
+        /// <summary>
+        /// Controls whether or not we actually report the failure.
+        /// There are situations where we know we're in a bad state and any further reports are unlikely to be
+        /// helpful, so we shouldn't send them.
+        /// </summary>
+        private static bool s_reportWatson = true;
+
         /// <summary>
         /// Report Non-Fatal Watson
         /// </summary>
@@ -44,6 +51,11 @@ public static void Report(string description, Exception exception)
         /// CAB.</param>
         public static void Report(string description, Exception exception, Func<IFaultUtility, int> callback)
         {
+            if (!s_reportWatson)
+            {
+                return;
+            }
+
             TelemetryService.DefaultSession.PostFault(
                 eventName: FunctionId.NonFatalWatson.GetEventName(),
                 description: description,
@@ -54,6 +66,14 @@ public static void Report(string description, Exception exception, Func<IFaultUt
                     arg.AddProcessDump(System.Diagnostics.Process.GetCurrentProcess().Id);
                     return callback(arg);
                 });
+
+            if (exception is OutOfMemoryException)
+            {
+                // Once we've encountered one OOM we're likely to see more. There will probably be other
+                // failures as a direct result of the OOM, as well. These aren't helpful so we should just
+                // stop reporting failures.
+                s_reportWatson = false;
+            }
         }
     }
 }

From e8e054f51b80da1229d54b543e332a5dac0cbc84 Mon Sep 17 00:00:00 2001
From: Heejae Chang <hechang@microsoft.com>
Date: Wed, 2 Aug 2017 16:06:47 -0700
Subject: [PATCH 25/77] removed semantic version tracking code which recently
 caused some issue on RPS test. this code is already removed from master
 (15.5)

---
 ...WorkCoordinator.NormalPriorityProcessor.cs |  29 ---
 .../SolutionCrawler/WorkCoordinator.cs        |  28 ---
 .../SemanticVersionTrackingService.cs         | 229 ------------------
 .../Core/Def/ServicesVisualStudio.csproj      |   9 +-
 .../Core/Portable/Versions/Extensions.cs      |  35 ---
 .../ISemanticVersionTrackingService.cs        |  21 --
 .../Versions/PersistedVersionStampLogger.cs   |  47 ----
 .../Core/Portable/Workspaces.csproj           |   1 -
 8 files changed, 4 insertions(+), 395 deletions(-)
 delete mode 100644 src/VisualStudio/Core/Def/Implementation/Versions/SemanticVersionTrackingService.cs
 delete mode 100644 src/Workspaces/Core/Portable/Versions/ISemanticVersionTrackingService.cs

diff --git a/src/Features/Core/Portable/SolutionCrawler/WorkCoordinator.NormalPriorityProcessor.cs b/src/Features/Core/Portable/SolutionCrawler/WorkCoordinator.NormalPriorityProcessor.cs
index 18085f91c6d1e..5f55849cdbb6a 100644
--- a/src/Features/Core/Portable/SolutionCrawler/WorkCoordinator.NormalPriorityProcessor.cs
+++ b/src/Features/Core/Portable/SolutionCrawler/WorkCoordinator.NormalPriorityProcessor.cs
@@ -321,8 +321,6 @@ private async Task ProcessDocumentAsync(ImmutableArray<IIncrementalAnalyzer> ana
 
                                 if (document != null)
                                 {
-                                    await TrackSemanticVersionsAsync(document, workItem, cancellationToken).ConfigureAwait(false);
-
                                     // if we are called because a document is opened, we invalidate the document so that
                                     // it can be re-analyzed. otherwise, since newly opened document has same version as before
                                     // analyzer will simply return same data back
@@ -372,33 +370,6 @@ private async Task ProcessDocumentAsync(ImmutableArray<IIncrementalAnalyzer> ana
                         }
                     }
 
-                    private async Task TrackSemanticVersionsAsync(Document document, WorkItem workItem, CancellationToken cancellationToken)
-                    {
-                        if (workItem.IsRetry ||
-                            workItem.InvocationReasons.Contains(PredefinedInvocationReasons.DocumentAdded) ||
-                            !workItem.InvocationReasons.Contains(PredefinedInvocationReasons.SyntaxChanged))
-                        {
-                            return;
-                        }
-
-                        var service = document.Project.Solution.Workspace.Services.GetService<ISemanticVersionTrackingService>();
-                        if (service == null)
-                        {
-                            return;
-                        }
-
-                        // we already reported about this project for same snapshot, don't need to do it again
-                        if (_currentSnapshotVersionTrackingSet.Contains(document.Project.Id))
-                        {
-                            return;
-                        }
-
-                        await service.RecordSemanticVersionsAsync(document.Project, cancellationToken).ConfigureAwait(false);
-
-                        // mark this project as already processed.
-                        _currentSnapshotVersionTrackingSet.Add(document.Project.Id);
-                    }
-
                     private async Task ProcessOpenDocumentIfNeeded(ImmutableArray<IIncrementalAnalyzer> analyzers, WorkItem workItem, Document document, bool isOpen, CancellationToken cancellationToken)
                     {
                         if (!isOpen || !workItem.InvocationReasons.Contains(PredefinedInvocationReasons.DocumentOpened))
diff --git a/src/Features/Core/Portable/SolutionCrawler/WorkCoordinator.cs b/src/Features/Core/Portable/SolutionCrawler/WorkCoordinator.cs
index 1b41233221513..d0570c83fcd3f 100644
--- a/src/Features/Core/Portable/SolutionCrawler/WorkCoordinator.cs
+++ b/src/Features/Core/Portable/SolutionCrawler/WorkCoordinator.cs
@@ -296,7 +296,6 @@ private void ProcessProjectEvent(WorkspaceChangeEventArgs e, IAsyncToken asyncTo
                 switch (e.Kind)
                 {
                     case WorkspaceChangeKind.ProjectAdded:
-                        OnProjectAdded(e.NewSolution.GetProject(e.ProjectId));
                         EnqueueEvent(e.NewSolution, e.ProjectId, InvocationReasons.DocumentAdded, asyncToken);
                         break;
                     case WorkspaceChangeKind.ProjectRemoved:
@@ -316,7 +315,6 @@ private void ProcessSolutionEvent(WorkspaceChangeEventArgs e, IAsyncToken asyncT
                 switch (e.Kind)
                 {
                     case WorkspaceChangeKind.SolutionAdded:
-                        OnSolutionAdded(e.NewSolution);
                         EnqueueEvent(e.NewSolution, InvocationReasons.DocumentAdded, asyncToken);
                         break;
                     case WorkspaceChangeKind.SolutionRemoved:
@@ -334,32 +332,6 @@ private void ProcessSolutionEvent(WorkspaceChangeEventArgs e, IAsyncToken asyncT
                 }
             }
 
-            private void OnSolutionAdded(Solution solution)
-            {
-                var asyncToken = _listener.BeginAsyncOperation("OnSolutionAdded");
-                _eventProcessingQueue.ScheduleTask(() =>
-                {
-                    var semanticVersionTrackingService = solution.Workspace.Services.GetService<ISemanticVersionTrackingService>();
-                    if (semanticVersionTrackingService != null)
-                    {
-                        semanticVersionTrackingService.LoadInitialSemanticVersions(solution);
-                    }
-                }, _shutdownToken).CompletesAsyncOperation(asyncToken);
-            }
-
-            private void OnProjectAdded(Project project)
-            {
-                var asyncToken = _listener.BeginAsyncOperation("OnProjectAdded");
-                _eventProcessingQueue.ScheduleTask(() =>
-                {
-                    var semanticVersionTrackingService = project.Solution.Workspace.Services.GetService<ISemanticVersionTrackingService>();
-                    if (semanticVersionTrackingService != null)
-                    {
-                        semanticVersionTrackingService.LoadInitialSemanticVersions(project);
-                    }
-                }, _shutdownToken).CompletesAsyncOperation(asyncToken);
-            }
-
             private void EnqueueEvent(Solution oldSolution, Solution newSolution, IAsyncToken asyncToken)
             {
                 _eventProcessingQueue.ScheduleTask(
diff --git a/src/VisualStudio/Core/Def/Implementation/Versions/SemanticVersionTrackingService.cs b/src/VisualStudio/Core/Def/Implementation/Versions/SemanticVersionTrackingService.cs
deleted file mode 100644
index 26a7cd83b8f83..0000000000000
--- a/src/VisualStudio/Core/Def/Implementation/Versions/SemanticVersionTrackingService.cs
+++ /dev/null
@@ -1,229 +0,0 @@
-// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
-
-using System;
-using System.Composition;
-using System.IO;
-using System.Runtime.CompilerServices;
-using System.Threading;
-using System.Threading.Tasks;
-using Microsoft.CodeAnalysis;
-using Microsoft.CodeAnalysis.Host;
-using Microsoft.CodeAnalysis.Host.Mef;
-using Microsoft.CodeAnalysis.Shared.Extensions;
-using Microsoft.CodeAnalysis.Shared.Utilities;
-using Microsoft.CodeAnalysis.Versions;
-using Roslyn.Utilities;
-
-namespace Microsoft.VisualStudio.LanguageServices.Implementation.Versions
-{
-    /// <summary>
-    /// this service tracks semantic version changes as solution changes and provide a way to get back to initial project/semantic version
-    /// pairs at the solution load 
-    /// </summary>
-    [ExportWorkspaceService(typeof(ISemanticVersionTrackingService), ServiceLayer.Host), Shared]
-    internal class SemanticVersionTrackingService : ISemanticVersionTrackingService
-    {
-        private const int SerializationFormat = 1;
-        private const string SemanticVersion = nameof(SemanticVersion);
-        private const string DependentSemanticVersion = nameof(DependentSemanticVersion);
-
-        private static readonly ConditionalWeakTable<ProjectId, Versions> s_initialSemanticVersions = new ConditionalWeakTable<ProjectId, Versions>();
-        private static readonly ConditionalWeakTable<ProjectId, Versions> s_initialDependentSemanticVersions = new ConditionalWeakTable<ProjectId, Versions>();
-
-        public VersionStamp GetInitialProjectVersionFromSemanticVersion(Project project, VersionStamp semanticVersion)
-        {
-            if (!TryGetInitialVersions(s_initialSemanticVersions, project, SemanticVersion, out var versions))
-            {
-                return VersionStamp.Default;
-            }
-
-            if (!VersionStamp.CanReusePersistedVersion(semanticVersion, versions.SemanticVersion))
-            {
-                return VersionStamp.Default;
-            }
-
-            return versions.ProjectVersion;
-        }
-
-        public VersionStamp GetInitialDependentProjectVersionFromDependentSemanticVersion(Project project, VersionStamp dependentSemanticVersion)
-        {
-            if (!TryGetInitialVersions(s_initialDependentSemanticVersions, project, DependentSemanticVersion, out var versions))
-            {
-                return VersionStamp.Default;
-            }
-
-            if (!VersionStamp.CanReusePersistedVersion(dependentSemanticVersion, versions.SemanticVersion))
-            {
-                return VersionStamp.Default;
-            }
-
-            return versions.ProjectVersion;
-        }
-
-        private bool TryGetInitialVersions(ConditionalWeakTable<ProjectId, Versions> initialVersionMap, Project project, string keyName, out Versions versions)
-        {
-            // if we already loaded this, return it.
-            if (initialVersionMap.TryGetValue(project.Id, out versions))
-            {
-                return true;
-            }
-
-            // otherwise, load it
-            return TryLoadInitialVersions(initialVersionMap, project, keyName, out versions);
-        }
-
-        public void LoadInitialSemanticVersions(Solution solution)
-        {
-            foreach (var project in solution.Projects)
-            {
-                LoadInitialSemanticVersions(project);
-            }
-        }
-
-        public void LoadInitialSemanticVersions(Project project)
-        {
-            if (!s_initialSemanticVersions.TryGetValue(project.Id, out var unused))
-            {
-                PersistedVersionStampLogger.LogProject();
-
-                if (TryLoadInitialVersions(s_initialSemanticVersions, project, SemanticVersion, out unused))
-                {
-                    PersistedVersionStampLogger.LogInitialSemanticVersion();
-                }
-            }
-
-            if (!s_initialDependentSemanticVersions.TryGetValue(project.Id, out unused) &&
-                TryLoadInitialVersions(s_initialDependentSemanticVersions, project, DependentSemanticVersion, out unused))
-            {
-                PersistedVersionStampLogger.LogInitialDependentSemanticVersion();
-            }
-        }
-
-        private bool TryLoadInitialVersions(ConditionalWeakTable<ProjectId, Versions> initialVersionMap, Project project, string keyName, out Versions versions)
-        {
-            var result = TryReadFrom(project, keyName, out versions);
-            if (result)
-            {
-                Versions save = versions;
-                initialVersionMap.GetValue(project.Id, _ => save);
-                return true;
-            }
-
-            initialVersionMap.GetValue(project.Id, _ => Versions.Default);
-            return false;
-        }
-
-        private static bool TryReadFrom(Project project, string keyName, out Versions versions)
-        {
-            versions = default(Versions);
-
-            var service = project.Solution.Workspace.Services.GetService<IPersistentStorageService>();
-            if (service == null)
-            {
-                return false;
-            }
-
-            try
-            {
-                using (var storage = service.GetStorage(project.Solution))
-                using (var stream = storage.ReadStreamAsync(keyName, CancellationToken.None).WaitAndGetResult(CancellationToken.None))
-                using (var reader = ObjectReader.TryGetReader(stream))
-                {
-                    if (reader != null)
-                    {
-                        var formatVersion = reader.ReadInt32();
-                        if (formatVersion == SerializationFormat)
-                        {
-                            var persistedProjectVersion = VersionStamp.ReadFrom(reader);
-                            var persistedSemanticVersion = VersionStamp.ReadFrom(reader);
-
-                            versions = new Versions(persistedProjectVersion, persistedSemanticVersion);
-                            return true;
-                        }
-                    }
-                }
-            }
-            catch (Exception e) when (IOUtilities.IsNormalIOException(e))
-            {
-            }
-
-            return false;
-        }
-
-        public async Task RecordSemanticVersionsAsync(Project project, CancellationToken cancellationToken)
-        {
-            var service = project.Solution.Workspace.Services.GetService<IPersistentStorageService>();
-            if (service == null)
-            {
-                return;
-            }
-
-            using (var storage = service.GetStorage(project.Solution))
-            {
-                // first update semantic and dependent semantic version of this project
-                await WriteToSemanticVersionAsync(storage, project, cancellationToken).ConfigureAwait(false);
-                await WriteToDependentSemanticVersionAsync(storage, project, cancellationToken).ConfigureAwait(false);
-
-                // next update dependent semantic version fo all projects that depend on this project.
-                var projectIds = project.Solution.GetProjectDependencyGraph().GetProjectsThatTransitivelyDependOnThisProject(project.Id);
-                foreach (var projectId in projectIds)
-                {
-                    cancellationToken.ThrowIfCancellationRequested();
-
-                    var currentProject = project.Solution.GetProject(projectId);
-                    if (currentProject == null)
-                    {
-                        continue;
-                    }
-
-                    await WriteToDependentSemanticVersionAsync(storage, currentProject, cancellationToken).ConfigureAwait(false);
-                }
-            }
-        }
-
-        private static async Task WriteToSemanticVersionAsync(IPersistentStorage storage, Project project, CancellationToken cancellationToken)
-        {
-            var projectVersion = await project.GetVersionAsync(cancellationToken).ConfigureAwait(false);
-            var semanticVersion = await project.GetSemanticVersionAsync(cancellationToken).ConfigureAwait(false);
-
-            await WriteToVersionAsync(storage, SemanticVersion, projectVersion, semanticVersion, cancellationToken).ConfigureAwait(false);
-        }
-
-        private static async Task WriteToDependentSemanticVersionAsync(IPersistentStorage storage, Project project, CancellationToken cancellationToken)
-        {
-            var projectVersion = await project.GetDependentVersionAsync(cancellationToken).ConfigureAwait(false);
-            var semanticVersion = await project.GetDependentSemanticVersionAsync(cancellationToken).ConfigureAwait(false);
-
-            await WriteToVersionAsync(storage, DependentSemanticVersion, projectVersion, semanticVersion, cancellationToken).ConfigureAwait(false);
-        }
-
-        private static async Task WriteToVersionAsync(
-            IPersistentStorage storage, string keyName, VersionStamp projectVersion, VersionStamp semanticVersion, CancellationToken cancellationToken)
-        {
-            using (var stream = SerializableBytes.CreateWritableStream())
-            using (var writer = new ObjectWriter(stream, cancellationToken: cancellationToken))
-            {
-                writer.WriteInt32(SerializationFormat);
-                projectVersion.WriteTo(writer);
-                semanticVersion.WriteTo(writer);
-
-                stream.Position = 0;
-                await storage.WriteStreamAsync(keyName, stream, cancellationToken).ConfigureAwait(false);
-            }
-        }
-
-        private class Versions
-        {
-            public static readonly Versions Default = new Versions(VersionStamp.Default, VersionStamp.Default);
-
-            public readonly VersionStamp ProjectVersion;
-            public readonly VersionStamp SemanticVersion;
-
-            public Versions(VersionStamp projectVersion, VersionStamp semanticVersion)
-            {
-                this.ProjectVersion = projectVersion;
-                this.SemanticVersion = semanticVersion;
-            }
-        }
-    }
-}
diff --git a/src/VisualStudio/Core/Def/ServicesVisualStudio.csproj b/src/VisualStudio/Core/Def/ServicesVisualStudio.csproj
index aa719b6acce9d..5095e9c4f19b8 100644
--- a/src/VisualStudio/Core/Def/ServicesVisualStudio.csproj
+++ b/src/VisualStudio/Core/Def/ServicesVisualStudio.csproj
@@ -159,7 +159,6 @@
     <Compile Include="Implementation\Utilities\AutomationDelegatingListView.cs" />
     <Compile Include="Implementation\Utilities\HyperlinkStyleHelper.cs" />
     <Compile Include="Implementation\Venus\VenusTaskExtensions.cs" />
-    <Compile Include="Implementation\Versions\SemanticVersionTrackingService.cs" />
     <Compile Include="Implementation\ContainedLanguageRefactorNotifyService.cs" />
     <Compile Include="Implementation\VirtualMemoryNotificationListener.cs" />
     <Compile Include="Implementation\Watson\WatsonReporter.cs" />
@@ -346,7 +345,7 @@
     <PackageReference Include="Microsoft.VisualStudio.Shell.Interop.15.0.DesignTime">
       <Version>$(MicrosoftVisualStudioShellInterop150DesignTimeVersion)</Version>
     </PackageReference>
-	 <PackageReference Include="Microsoft.VisualStudio.Shell.Interop.15.3.DesignTime">
+    <PackageReference Include="Microsoft.VisualStudio.Shell.Interop.15.3.DesignTime">
       <Version>$(MicrosoftVisualStudioShellInterop153DesignTimeVersion)</Version>
     </PackageReference>
     <PackageReference Include="Microsoft.VisualStudio.Shell.15.0">
@@ -451,9 +450,9 @@
     <PackageReference Include="Newtonsoft.Json">
       <Version>$(NewtonsoftJsonVersion)</Version>
     </PackageReference>
-	<PackageReference Include="Microsoft.VisualStudio.Shell.Interop.15.3.DesignTime">
-		<Version>$(MicrosoftVisualStudioShellInterop153DesignTimeVersion)</Version>
-	</PackageReference>
+    <PackageReference Include="Microsoft.VisualStudio.Shell.Interop.15.3.DesignTime">
+      <Version>$(MicrosoftVisualStudioShellInterop153DesignTimeVersion)</Version>
+    </PackageReference>
   </ItemGroup>
   <ItemGroup>
     <Compile Include="CodeMarkers\ManagedCodeMarkers.cs" />
diff --git a/src/Workspaces/Core/Portable/Versions/Extensions.cs b/src/Workspaces/Core/Portable/Versions/Extensions.cs
index 583d9a35e8500..348c0ff0c6e90 100644
--- a/src/Workspaces/Core/Portable/Versions/Extensions.cs
+++ b/src/Workspaces/Core/Portable/Versions/Extensions.cs
@@ -37,40 +37,5 @@ public static bool CanReusePersistedDependentProjectVersion(this Project project
             PersistedVersionStampLogger.LogPersistedDependentProjectVersionUsage(canReuse);
             return canReuse;
         }
-
-        public static bool CanReusePersistedSemanticVersion(
-            this Project project, VersionStamp projectVersion, VersionStamp semanticVersion, VersionStamp persistedVersion)
-        {
-            var canReuse = CanReusePersistedSemanticVersionInternal(
-                project, projectVersion, semanticVersion, persistedVersion, (s, p, v) => s.GetInitialProjectVersionFromSemanticVersion(p, v));
-
-            PersistedVersionStampLogger.LogPersistedSemanticVersionUsage(canReuse);
-            return canReuse;
-        }
-
-        public static bool CanReusePersistedDependentSemanticVersion(
-            this Project project, VersionStamp dependentProjectVersion, VersionStamp dependentSemanticVersion, VersionStamp persistedVersion)
-        {
-            var canReuse = CanReusePersistedSemanticVersionInternal(
-                project, dependentProjectVersion, dependentSemanticVersion, persistedVersion, (s, p, v) => s.GetInitialDependentProjectVersionFromDependentSemanticVersion(p, v));
-
-            PersistedVersionStampLogger.LogPersistedDependentSemanticVersionUsage(canReuse);
-            return canReuse;
-        }
-
-        private static bool CanReusePersistedSemanticVersionInternal(
-            Project project,
-            VersionStamp projectVersion,
-            VersionStamp semanticVersion,
-            VersionStamp persistedVersion,
-            Func<ISemanticVersionTrackingService, Project, VersionStamp, VersionStamp> versionGetter)
-        {
-            // * NOTE * 
-            // Disabled semantic version tracking
-            // we need better version for it to reliably work.
-            //
-            // see tracking issue here : https://github.com/dotnet/roslyn/issues/2311
-            return VersionStamp.CanReusePersistedVersion(semanticVersion, persistedVersion);
-        }
     }
 }
diff --git a/src/Workspaces/Core/Portable/Versions/ISemanticVersionTrackingService.cs b/src/Workspaces/Core/Portable/Versions/ISemanticVersionTrackingService.cs
deleted file mode 100644
index e425ce701f721..0000000000000
--- a/src/Workspaces/Core/Portable/Versions/ISemanticVersionTrackingService.cs
+++ /dev/null
@@ -1,21 +0,0 @@
-// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
-
-using System.Threading;
-using System.Threading.Tasks;
-using Microsoft.CodeAnalysis.Host;
-
-namespace Microsoft.CodeAnalysis.Versions
-{
-    /// <summary>
-    /// A service that knows how to convert semantic version to project version
-    /// </summary>
-    internal interface ISemanticVersionTrackingService : IWorkspaceService
-    {
-        VersionStamp GetInitialProjectVersionFromSemanticVersion(Project project, VersionStamp semanticVersion);
-        VersionStamp GetInitialDependentProjectVersionFromDependentSemanticVersion(Project project, VersionStamp dependentSemanticVersion);
-
-        void LoadInitialSemanticVersions(Solution solution);
-        void LoadInitialSemanticVersions(Project project);
-        Task RecordSemanticVersionsAsync(Project project, CancellationToken cancellationToken);
-    }
-}
diff --git a/src/Workspaces/Core/Portable/Versions/PersistedVersionStampLogger.cs b/src/Workspaces/Core/Portable/Versions/PersistedVersionStampLogger.cs
index c0c233d67899c..c81219b957555 100644
--- a/src/Workspaces/Core/Portable/Versions/PersistedVersionStampLogger.cs
+++ b/src/Workspaces/Core/Portable/Versions/PersistedVersionStampLogger.cs
@@ -11,12 +11,6 @@ internal static class PersistedVersionStampLogger
         private const string SyntaxTree = nameof(SyntaxTree);
         private const string Project = nameof(Project);
         private const string DependentProject = nameof(DependentProject);
-        private const string Semantic = nameof(Semantic);
-        private const string DependentSemantic = nameof(DependentSemantic);
-
-        private const string ProjectCount = nameof(ProjectCount);
-        private const string InitialSemanticVersionCount = nameof(InitialSemanticVersionCount);
-        private const string InitialDependentSemanticVersionCount = nameof(InitialDependentSemanticVersionCount);
 
         private static readonly LogAggregator s_logAggregator = new LogAggregator();
 
@@ -60,55 +54,14 @@ public static void LogPersistedDependentProjectVersionUsage(bool succeeded)
             s_logAggregator.IncreaseCount(DependentProject);
         }
 
-        public static void LogPersistedSemanticVersionUsage(bool succeeded)
-        {
-            if (!succeeded)
-            {
-                return;
-            }
-
-            s_logAggregator.IncreaseCount(Semantic);
-        }
-
-        public static void LogPersistedDependentSemanticVersionUsage(bool succeeded)
-        {
-            if (!succeeded)
-            {
-                return;
-            }
-
-            s_logAggregator.IncreaseCount(DependentSemantic);
-        }
-
-        public static void LogProject()
-        {
-            s_logAggregator.IncreaseCount(ProjectCount);
-        }
-
-        public static void LogInitialSemanticVersion()
-        {
-            s_logAggregator.IncreaseCount(InitialSemanticVersionCount);
-        }
-
-        public static void LogInitialDependentSemanticVersion()
-        {
-            s_logAggregator.IncreaseCount(InitialDependentSemanticVersionCount);
-        }
-
         public static void LogSummary()
         {
             Logger.Log(FunctionId.PersistedSemanticVersion_Info, KeyValueLogMessage.Create(m =>
             {
-                m[ProjectCount] = s_logAggregator.GetCount(ProjectCount);
-                m[InitialSemanticVersionCount] = s_logAggregator.GetCount(InitialSemanticVersionCount);
-                m[InitialDependentSemanticVersionCount] = s_logAggregator.GetCount(InitialDependentSemanticVersionCount);
-
                 m[Text] = s_logAggregator.GetCount(Text);
                 m[SyntaxTree] = s_logAggregator.GetCount(SyntaxTree);
                 m[Project] = s_logAggregator.GetCount(Project);
                 m[DependentProject] = s_logAggregator.GetCount(DependentProject);
-                m[Semantic] = s_logAggregator.GetCount(Semantic);
-                m[DependentSemantic] = s_logAggregator.GetCount(DependentSemantic);
             }));
         }
     }
diff --git a/src/Workspaces/Core/Portable/Workspaces.csproj b/src/Workspaces/Core/Portable/Workspaces.csproj
index 28273206767e3..26d924f6caffd 100644
--- a/src/Workspaces/Core/Portable/Workspaces.csproj
+++ b/src/Workspaces/Core/Portable/Workspaces.csproj
@@ -636,7 +636,6 @@
     <Compile Include="Utilities\ValuesSources\CachedWeakValueSource.cs" />
     <Compile Include="Utilities\WeakEventHandler.cs" />
     <Compile Include="Versions\Extensions.cs" />
-    <Compile Include="Versions\ISemanticVersionTrackingService.cs" />
     <Compile Include="Versions\PersistedVersionStampLogger.cs" />
     <Compile Include="Workspace\AdhocWorkspace.cs" />
     <Compile Include="Workspace\DocumentActiveContextChangedEventArgs.cs" />

From af99d1873f13c7a82c034b2d8016403fd90f580d Mon Sep 17 00:00:00 2001
From: Ivan Basov <basov@hotmail.com>
Date: Tue, 8 Aug 2017 10:40:25 -0700
Subject: [PATCH 26/77] CSharpLanguageInstructionDecoder implementation of
 IDkmLanguageInstructionDecoder is slow (#20834) (#21315)

---
 .../CSharpExpressionCompiler.cs               |  6 +++++
 .../CSharpInstructionDecoder.cs               |  2 +-
 .../Source/ExpressionCompiler/DkmUtilities.cs | 25 ++++++++++++++---
 .../ExpressionCompiler/ExpressionCompiler.cs  | 27 +++++++++++--------
 .../VisualBasicExpressionCompiler.vb          |  5 ++++
 .../VisualBasicInstructionDecoder.vb          |  2 +-
 6 files changed, 51 insertions(+), 16 deletions(-)

diff --git a/src/ExpressionEvaluator/CSharp/Source/ExpressionCompiler/CSharpExpressionCompiler.cs b/src/ExpressionEvaluator/CSharp/Source/ExpressionCompiler/CSharpExpressionCompiler.cs
index 7eff5085f2a37..88443a4acfbe1 100644
--- a/src/ExpressionEvaluator/CSharp/Source/ExpressionCompiler/CSharpExpressionCompiler.cs
+++ b/src/ExpressionEvaluator/CSharp/Source/ExpressionCompiler/CSharpExpressionCompiler.cs
@@ -108,5 +108,11 @@ internal override void RemoveDataItem(DkmClrAppDomain appDomain)
         {
             appDomain.RemoveMetadataContext<CSharpMetadataContext>();
         }
+
+        internal override ImmutableArray<MetadataBlock> GetMetadataBlocks(DkmClrAppDomain appDomain, DkmClrRuntimeInstance runtimeInstance)
+        {
+            var previous = appDomain.GetMetadataContext<CSharpMetadataContext>();
+            return runtimeInstance.GetMetadataBlocks(appDomain, previous.MetadataBlocks);
+        }
     }
 }
diff --git a/src/ExpressionEvaluator/CSharp/Source/ExpressionCompiler/CSharpInstructionDecoder.cs b/src/ExpressionEvaluator/CSharp/Source/ExpressionCompiler/CSharpInstructionDecoder.cs
index 9c19a8acbcc8c..57e912bb4f2c2 100644
--- a/src/ExpressionEvaluator/CSharp/Source/ExpressionCompiler/CSharpInstructionDecoder.cs
+++ b/src/ExpressionEvaluator/CSharp/Source/ExpressionCompiler/CSharpInstructionDecoder.cs
@@ -134,7 +134,7 @@ internal override CSharpCompilation GetCompilation(DkmClrModuleInstance moduleIn
         {
             var appDomain = moduleInstance.AppDomain;
             var previous = appDomain.GetMetadataContext<CSharpMetadataContext>();
-            var metadataBlocks = moduleInstance.RuntimeInstance.GetMetadataBlocks(appDomain);
+            var metadataBlocks = moduleInstance.RuntimeInstance.GetMetadataBlocks(appDomain, previous.MetadataBlocks);
 
             CSharpCompilation compilation;
             if (previous.Matches(metadataBlocks))
diff --git a/src/ExpressionEvaluator/Core/Source/ExpressionCompiler/DkmUtilities.cs b/src/ExpressionEvaluator/Core/Source/ExpressionCompiler/DkmUtilities.cs
index 5fc1731675164..677f2f3ea2c29 100644
--- a/src/ExpressionEvaluator/Core/Source/ExpressionCompiler/DkmUtilities.cs
+++ b/src/ExpressionEvaluator/Core/Source/ExpressionCompiler/DkmUtilities.cs
@@ -42,11 +42,15 @@ private static IEnumerable<DkmClrModuleInstance> GetModulesInAppDomain(this DkmC
                 });
         }
 
-        internal unsafe static ImmutableArray<MetadataBlock> GetMetadataBlocks(this DkmClrRuntimeInstance runtime, DkmClrAppDomain appDomain)
+        internal static ImmutableArray<MetadataBlock> GetMetadataBlocks(
+            this DkmClrRuntimeInstance runtime, 
+            DkmClrAppDomain appDomain, 
+            ImmutableArray<MetadataBlock> previousMetadataBlocks)
         {
             var builder = ArrayBuilder<MetadataBlock>.GetInstance();
             IntPtr ptr;
             uint size;
+            int index = 0;
             foreach (DkmClrModuleInstance module in runtime.GetModulesInAppDomain(appDomain))
             {
                 MetadataBlock block;
@@ -54,7 +58,7 @@ internal unsafe static ImmutableArray<MetadataBlock> GetMetadataBlocks(this DkmC
                 {
                     ptr = module.GetMetaDataBytesPtr(out size);
                     Debug.Assert(size > 0);
-                    block = GetMetadataBlock(ptr, size);
+                    block = GetMetadataBlock(previousMetadataBlocks, index, ptr, size);
                 }
                 catch (NotImplementedException e) when (module is DkmClrNcModuleInstance)
                 {
@@ -67,10 +71,11 @@ internal unsafe static ImmutableArray<MetadataBlock> GetMetadataBlocks(this DkmC
                 }
                 Debug.Assert(block.ModuleVersionId == module.Mvid);
                 builder.Add(block);
+                index++;
             }
             // Include "intrinsic method" assembly.
             ptr = runtime.GetIntrinsicAssemblyMetaDataBytesPtr(out size);
-            builder.Add(GetMetadataBlock(ptr, size));
+            builder.Add(GetMetadataBlock(previousMetadataBlocks, index, ptr, size));
             return builder.ToImmutableAndFree();
         }
 
@@ -141,6 +146,20 @@ private unsafe static MetadataBlock GetMetadataBlock(IntPtr ptr, uint size)
             return new MetadataBlock(moduleVersionId, generationId, ptr, (int)size);
         }
 
+        private static MetadataBlock GetMetadataBlock(ImmutableArray<MetadataBlock> previousMetadataBlocks, int index, IntPtr ptr, uint size)
+        {
+            if (!previousMetadataBlocks.IsDefault && index < previousMetadataBlocks.Length)
+            {
+                var previousBlock = previousMetadataBlocks[index];
+                if (previousBlock.Pointer == ptr && previousBlock.Size == size)
+                {
+                    return previousBlock;
+                }
+            }
+
+            return GetMetadataBlock(ptr, size);
+        }
+
         internal static object GetSymReader(this DkmClrModuleInstance clrModule)
         {
             var module = clrModule.Module; // Null if there are no symbols.
diff --git a/src/ExpressionEvaluator/Core/Source/ExpressionCompiler/ExpressionCompiler.cs b/src/ExpressionEvaluator/Core/Source/ExpressionCompiler/ExpressionCompiler.cs
index bfd298e576805..313764e2090ad 100644
--- a/src/ExpressionEvaluator/Core/Source/ExpressionCompiler/ExpressionCompiler.cs
+++ b/src/ExpressionEvaluator/Core/Source/ExpressionCompiler/ExpressionCompiler.cs
@@ -41,8 +41,8 @@ static ExpressionCompiler()
                     : GetAliases(runtimeInstance, inspectionContext); // NB: Not affected by retrying.
                 string error;
                 var r = this.CompileWithRetry(
-                    moduleInstance,
-                    runtimeInstance.GetMetadataBlocks(moduleInstance.AppDomain),
+                    moduleInstance.AppDomain,
+                    runtimeInstance,
                     (blocks, useReferencedModulesOnly) => CreateMethodContext(instructionAddress, blocks, useReferencedModulesOnly),
                     (context, diagnostics) =>
                     {
@@ -104,8 +104,8 @@ private static ImmutableArray<Alias> GetAliases(DkmClrRuntimeInstance runtimeIns
                 var runtimeInstance = instructionAddress.RuntimeInstance;
                 var aliases = GetAliases(runtimeInstance, inspectionContext); // NB: Not affected by retrying.
                 var r = this.CompileWithRetry(
-                    moduleInstance,
-                    runtimeInstance.GetMetadataBlocks(moduleInstance.AppDomain),
+                    moduleInstance.AppDomain,
+                    runtimeInstance,
                     (blocks, useReferencedModulesOnly) => CreateMethodContext(instructionAddress, blocks, useReferencedModulesOnly),
                     (context, diagnostics) =>
                     {
@@ -141,8 +141,8 @@ private static ImmutableArray<Alias> GetAliases(DkmClrRuntimeInstance runtimeIns
                 var runtimeInstance = instructionAddress.RuntimeInstance;
                 var aliases = GetAliases(runtimeInstance, lValue.InspectionContext); // NB: Not affected by retrying.
                 var r = this.CompileWithRetry(
-                    moduleInstance,
-                    runtimeInstance.GetMetadataBlocks(moduleInstance.AppDomain),
+                    moduleInstance.AppDomain,
+                    runtimeInstance,
                     (blocks, useReferencedModulesOnly) => CreateMethodContext(instructionAddress, blocks, useReferencedModulesOnly),
                     (context, diagnostics) =>
                     {
@@ -179,8 +179,8 @@ private static ImmutableArray<Alias> GetAliases(DkmClrRuntimeInstance runtimeIns
                 var runtimeInstance = moduleInstance.RuntimeInstance;
                 var appDomain = moduleInstance.AppDomain;
                 var compileResult = this.CompileWithRetry(
-                    moduleInstance,
-                    runtimeInstance.GetMetadataBlocks(appDomain),
+                    appDomain,
+                    runtimeInstance,
                     (blocks, useReferencedModulesOnly) => CreateTypeContext(appDomain, blocks, moduleInstance.Mvid, token, useReferencedModulesOnly),
                     (context, diagnostics) =>
                     {
@@ -265,6 +265,10 @@ private void RemoveDataItemIfNecessary(DkmModuleInstance moduleInstance)
 
         internal abstract void RemoveDataItem(DkmClrAppDomain appDomain);
 
+        internal abstract ImmutableArray<MetadataBlock> GetMetadataBlocks(
+            DkmClrAppDomain appDomain,
+            DkmClrRuntimeInstance runtimeInstance);
+
         private EvaluationContextBase CreateMethodContext(
             DkmClrInstructionAddress instructionAddress,
             ImmutableArray<MetadataBlock> metadataBlocks,
@@ -304,18 +308,19 @@ private void RemoveDataItemIfNecessary(DkmModuleInstance moduleInstance)
         internal delegate TResult CompileDelegate<TResult>(EvaluationContextBase context, DiagnosticBag diagnostics);
 
         private TResult CompileWithRetry<TResult>(
-            DkmClrModuleInstance moduleInstance,
-            ImmutableArray<MetadataBlock> metadataBlocks,
+            DkmClrAppDomain appDomain,
+            DkmClrRuntimeInstance runtimeInstance,
             CreateContextDelegate createContext,
             CompileDelegate<TResult> compile,
             out string errorMessage)
         {
+            var metadataBlocks = GetMetadataBlocks(appDomain, runtimeInstance);
             return CompileWithRetry(
                 metadataBlocks,
                 this.DiagnosticFormatter,
                 createContext,
                 compile,
-                (AssemblyIdentity assemblyIdentity, out uint size) => moduleInstance.AppDomain.GetMetaDataBytesPtr(assemblyIdentity.GetDisplayName(), out size),
+                (AssemblyIdentity assemblyIdentity, out uint size) => appDomain.GetMetaDataBytesPtr(assemblyIdentity.GetDisplayName(), out size),
                 out errorMessage);
         }
 
diff --git a/src/ExpressionEvaluator/VisualBasic/Source/ExpressionCompiler/VisualBasicExpressionCompiler.vb b/src/ExpressionEvaluator/VisualBasic/Source/ExpressionCompiler/VisualBasicExpressionCompiler.vb
index abd75ab2588e3..f32ba9a48da96 100644
--- a/src/ExpressionEvaluator/VisualBasic/Source/ExpressionCompiler/VisualBasicExpressionCompiler.vb
+++ b/src/ExpressionEvaluator/VisualBasic/Source/ExpressionCompiler/VisualBasicExpressionCompiler.vb
@@ -109,6 +109,11 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.ExpressionEvaluator
             appDomain.RemoveMetadataContext(Of VisualBasicMetadataContext)()
         End Sub
 
+        Friend Overrides Function GetMetadataBlocks(appDomain As DkmClrAppDomain, runtimeInstance As DkmClrRuntimeInstance) As ImmutableArray(Of MetadataBlock)
+            Dim previous = appDomain.GetMetadataContext(Of VisualBasicMetadataContext)()
+            Return runtimeInstance.GetMetadataBlocks(appDomain, previous.MetadataBlocks)
+        End Function
+
     End Class
 
 End Namespace
diff --git a/src/ExpressionEvaluator/VisualBasic/Source/ExpressionCompiler/VisualBasicInstructionDecoder.vb b/src/ExpressionEvaluator/VisualBasic/Source/ExpressionCompiler/VisualBasicInstructionDecoder.vb
index 74e4fc5761b00..8cb963e56948a 100644
--- a/src/ExpressionEvaluator/VisualBasic/Source/ExpressionCompiler/VisualBasicInstructionDecoder.vb
+++ b/src/ExpressionEvaluator/VisualBasic/Source/ExpressionCompiler/VisualBasicInstructionDecoder.vb
@@ -83,7 +83,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.ExpressionEvaluator
         Friend Overrides Function GetCompilation(moduleInstance As DkmClrModuleInstance) As VisualBasicCompilation
             Dim appDomain = moduleInstance.AppDomain
             Dim previous = appDomain.GetMetadataContext(Of VisualBasicMetadataContext)()
-            Dim metadataBlocks = moduleInstance.RuntimeInstance.GetMetadataBlocks(appDomain)
+            Dim metadataBlocks = moduleInstance.RuntimeInstance.GetMetadataBlocks(appDomain, previous.MetadataBlocks)
 
             Dim compilation As VisualBasicCompilation
             If previous.Matches(metadataBlocks) Then

From f5e5a5561033c17944a8d7f113dfafb3dd85d368 Mon Sep 17 00:00:00 2001
From: Sam Harwell <sam.harwell@microsoft.com>
Date: Tue, 8 Aug 2017 14:06:17 -0500
Subject: [PATCH 27/77] Add null checks for TaskExtensions before deferred
 execution

A null value for certain arguments in TaskExtensions results in an exception.
We want this exception to reveal the caller who passed a null value. This
commit updates methods which defer the evaluation of the argument to explicitly
check for null early so the caller is revealed in the stack trace.
---
 .../Core/Portable/Utilities/TaskExtensions.cs | 20 +++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/src/Workspaces/Core/Portable/Utilities/TaskExtensions.cs b/src/Workspaces/Core/Portable/Utilities/TaskExtensions.cs
index 2f1c4287eb833..5d027fd410976 100644
--- a/src/Workspaces/Core/Portable/Utilities/TaskExtensions.cs
+++ b/src/Workspaces/Core/Portable/Utilities/TaskExtensions.cs
@@ -90,6 +90,8 @@ public static T WaitAndGetResult_CanCallOnBackground<T>(this Task<T> task, Cance
             TaskContinuationOptions continuationOptions,
             TaskScheduler scheduler)
         {
+            Contract.ThrowIfNull(continuationAction, nameof(continuationAction));
+
             Func<Task, bool> continuationFunction = antecedent =>
             {
                 continuationAction(antecedent);
@@ -116,6 +118,8 @@ public static T WaitAndGetResult_CanCallOnBackground<T>(this Task<T> task, Cance
             TaskContinuationOptions continuationOptions,
             TaskScheduler scheduler)
         {
+            Contract.ThrowIfNull(continuationFunction, nameof(continuationFunction));
+
             return task.SafeContinueWith<TResult>(
                 (Task antecedent) => continuationFunction((Task<TInput>)antecedent), cancellationToken, continuationOptions, scheduler);
         }
@@ -127,6 +131,8 @@ public static T WaitAndGetResult_CanCallOnBackground<T>(this Task<T> task, Cance
             TaskContinuationOptions continuationOptions,
             TaskScheduler scheduler)
         {
+            Contract.ThrowIfNull(continuationAction, nameof(continuationAction));
+
             return task.SafeContinueWith(
                 (Task antecedent) => continuationAction((Task<TInput>)antecedent), cancellationToken, continuationOptions, scheduler);
         }
@@ -156,6 +162,8 @@ public static T WaitAndGetResult_CanCallOnBackground<T>(this Task<T> task, Cance
             // We do not want this, so we pass the LazyCancellation flag to the TPL which implements
             // the behavior we want.
 
+            Contract.ThrowIfNull(continuationFunction, nameof(continuationFunction));
+
             Func<Task, TResult> outerFunction = t =>
             {
                 try
@@ -223,6 +231,8 @@ public static T WaitAndGetResult_CanCallOnBackground<T>(this Task<T> task, Cance
             TaskContinuationOptions taskContinuationOptions,
             TaskScheduler scheduler)
         {
+            Contract.ThrowIfNull(continuationFunction, nameof(continuationFunction));
+
             return task.SafeContinueWith(t =>
                 Task.Delay(millisecondsDelay, cancellationToken).SafeContinueWith(
                     _ => continuationFunction(t), cancellationToken, TaskContinuationOptions.None, scheduler),
@@ -237,6 +247,8 @@ public static T WaitAndGetResult_CanCallOnBackground<T>(this Task<T> task, Cance
             TaskContinuationOptions taskContinuationOptions,
             TaskScheduler scheduler)
         {
+            Contract.ThrowIfNull(continuationFunction, nameof(continuationFunction));
+
             return task.SafeContinueWith(t =>
                 Task.Delay(millisecondsDelay, cancellationToken).SafeContinueWith(
                     _ => continuationFunction(t), cancellationToken, TaskContinuationOptions.None, scheduler),
@@ -251,6 +263,8 @@ public static T WaitAndGetResult_CanCallOnBackground<T>(this Task<T> task, Cance
             TaskContinuationOptions taskContinuationOptions,
             TaskScheduler scheduler)
         {
+            Contract.ThrowIfNull(continuationAction, nameof(continuationAction));
+
             return task.SafeContinueWith(t =>
                 Task.Delay(millisecondsDelay, cancellationToken).SafeContinueWith(
                     _ => continuationAction(), cancellationToken, TaskContinuationOptions.None, scheduler),
@@ -264,6 +278,8 @@ public static T WaitAndGetResult_CanCallOnBackground<T>(this Task<T> task, Cance
             TaskContinuationOptions continuationOptions,
             TaskScheduler scheduler)
         {
+            Contract.ThrowIfNull(continuationFunction, nameof(continuationFunction));
+
             return task.SafeContinueWithFromAsync<TResult>(
                 (Task antecedent) => continuationFunction((Task<TInput>)antecedent), cancellationToken, continuationOptions, scheduler);
         }
@@ -350,6 +366,8 @@ public static T WaitAndGetResult_CanCallOnBackground<T>(this Task<T> task, Cance
             TaskContinuationOptions taskContinuationOptions,
             TaskScheduler scheduler)
         {
+            Contract.ThrowIfNull(continuationFunction, nameof(continuationFunction));
+
             return task.SafeContinueWith(t =>
                 Task.Delay(millisecondsDelay, cancellationToken).SafeContinueWithFromAsync(
                     _ => continuationFunction(t), cancellationToken, TaskContinuationOptions.None, scheduler),
@@ -364,6 +382,8 @@ public static T WaitAndGetResult_CanCallOnBackground<T>(this Task<T> task, Cance
             TaskContinuationOptions taskContinuationOptions,
             TaskScheduler scheduler)
         {
+            Contract.ThrowIfNull(continuationFunction, nameof(continuationFunction));
+
             return task.SafeContinueWith(t =>
                 Task.Delay(millisecondsDelay, cancellationToken).SafeContinueWithFromAsync(
                     _ => continuationFunction(t), cancellationToken, TaskContinuationOptions.None, scheduler),

From 431582f45c579c40507fedbce147ba4571160a25 Mon Sep 17 00:00:00 2001
From: Heejae Chang <hechang@microsoft.com>
Date: Tue, 8 Aug 2017 16:39:22 -0700
Subject: [PATCH 28/77] moved to List from ImmutableArray on json return type.

ImmutableArray is causing isssue on Json lib. use regular List since we don't actually need immutable array here.
---
 .../IRemoteDesignerAttributeService.cs             |  4 ++--
 .../DesignerAttributeIncrementalAnalyzer.cs        |  2 +-
 .../CodeAnalysisService_DesignerAttributes.cs      | 14 +++++++++++---
 3 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/src/Features/Core/Portable/DesignerAttributes/IRemoteDesignerAttributeService.cs b/src/Features/Core/Portable/DesignerAttributes/IRemoteDesignerAttributeService.cs
index 5c915a4c9a39c..3f09f0a062bc9 100644
--- a/src/Features/Core/Portable/DesignerAttributes/IRemoteDesignerAttributeService.cs
+++ b/src/Features/Core/Portable/DesignerAttributes/IRemoteDesignerAttributeService.cs
@@ -1,6 +1,6 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
-using System.Collections.Immutable;
+using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
 
@@ -8,6 +8,6 @@ namespace Microsoft.CodeAnalysis.DesignerAttributes
 {
     internal interface IRemoteDesignerAttributeService
     {
-        Task<ImmutableArray<DesignerAttributeDocumentData>> ScanDesignerAttributesAsync(ProjectId projectId, CancellationToken cancellationToken);
+        Task<IList<DesignerAttributeDocumentData>> ScanDesignerAttributesAsync(ProjectId projectId, CancellationToken cancellationToken);
     }
 }
diff --git a/src/VisualStudio/Core/Def/Implementation/DesignerAttribute/DesignerAttributeIncrementalAnalyzer.cs b/src/VisualStudio/Core/Def/Implementation/DesignerAttribute/DesignerAttributeIncrementalAnalyzer.cs
index c974689d215a2..6ceaa77b5d7b7 100644
--- a/src/VisualStudio/Core/Def/Implementation/DesignerAttribute/DesignerAttributeIncrementalAnalyzer.cs
+++ b/src/VisualStudio/Core/Def/Implementation/DesignerAttribute/DesignerAttributeIncrementalAnalyzer.cs
@@ -130,7 +130,7 @@ public async Task AnalyzeProjectAsync(Project project, bool semanticsChanged, In
                     return null;
                 }
 
-                var serializedResults = await session.InvokeAsync<ImmutableArray<DesignerAttributeDocumentData>>(
+                var serializedResults = await session.InvokeAsync<IList<DesignerAttributeDocumentData>>(
                     nameof(IRemoteDesignerAttributeService.ScanDesignerAttributesAsync), new object[] { project.Id }, cancellationToken).ConfigureAwait(false);
 
                 var data = serializedResults.ToImmutableDictionary(kvp => kvp.FilePath);
diff --git a/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_DesignerAttributes.cs b/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_DesignerAttributes.cs
index bd4af79307a30..3aefc8e2ea1c3 100644
--- a/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_DesignerAttributes.cs
+++ b/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_DesignerAttributes.cs
@@ -1,10 +1,12 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
-using System.Collections.Immutable;
+using System.Collections.Generic;
+using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.DesignerAttributes;
 using Microsoft.CodeAnalysis.Internal.Log;
+using Roslyn.Utilities;
 using RoslynLogger = Microsoft.CodeAnalysis.Internal.Log.Logger;
 
 namespace Microsoft.CodeAnalysis.Remote
@@ -17,16 +19,22 @@ internal partial class CodeAnalysisService : IRemoteDesignerAttributeService
         /// 
         /// This will be called by ServiceHub/JsonRpc framework
         /// </summary>
-        public async Task<ImmutableArray<DesignerAttributeDocumentData>> ScanDesignerAttributesAsync(ProjectId projectId, CancellationToken cancellationToken)
+        public async Task<IList<DesignerAttributeDocumentData>> ScanDesignerAttributesAsync(ProjectId projectId, CancellationToken cancellationToken)
         {
             using (RoslynLogger.LogBlock(FunctionId.CodeAnalysisService_GetDesignerAttributesAsync, projectId.DebugName, cancellationToken))
             {
                 var solution = await GetSolutionAsync(cancellationToken).ConfigureAwait(false);
                 var project = solution.GetProject(projectId);
+
                 var data = await AbstractDesignerAttributeService.TryAnalyzeProjectInCurrentProcessAsync(
                     project, cancellationToken).ConfigureAwait(false);
 
-                return data.Values.ToImmutableArray();
+                if (data.Count == 0)
+                {
+                    return SpecializedCollections.EmptyList<DesignerAttributeDocumentData>();
+                }
+
+                return data.Values.ToList();
             }
         }
     }

From 97ca96e56fff79ec4d00c320fbc24ba2c4353e2d Mon Sep 17 00:00:00 2001
From: Heejae Chang <hechang@microsoft.com>
Date: Wed, 9 Aug 2017 12:44:57 -0700
Subject: [PATCH 29/77] moved all immutable array usage to IReadOnlyList

---
 .../AddUsing/AddUsingTests_NuGet.cs           |  6 ++---
 .../TodoCommentIncrementalAnalyzer.cs         |  6 ++---
 .../AddImport/AddImportTests_NuGet.vb         |  6 ++---
 ...pTodoCommentIncrementalAnalyzerProvider.cs |  2 +-
 .../AbstractAddImportFeatureService_Remote.cs |  7 ++---
 .../Remote/IRemoteAddImportFeatureService.cs  |  5 ++--
 ...olReferenceFinder_PackageAssemblySearch.cs |  4 +--
 .../IRemoteDocumentHighlights.cs              |  7 ++---
 .../IRemoteNavigateToSearchService.cs         |  5 ++--
 .../AbstractTodoCommentService.cs             | 20 +++++++-------
 .../TodoComments/IRemoteTodoCommentService.cs |  2 +-
 .../TodoComments/ITodoCommentService.cs       |  2 +-
 ...cTodoCommentIncrementalAnalyzerProvider.vb |  2 +-
 .../VisualStudioSymbolSearchService.cs        |  6 ++---
 .../FindSymbols/IRemoteSymbolFinder.cs        |  9 ++++---
 .../IRemoteSymbolSearchUpdateEngine.cs        |  7 ++---
 .../SymbolSearch/ISymbolSearchService.cs      | 26 +++++++++----------
 .../Portable/Utilities/SpecializedTasks.cs    | 12 +++++++++
 .../Services/CodeAnalysisService_AddImport.cs | 19 +++++++-------
 .../CodeAnalysisService_DocumentHighlights.cs |  3 ++-
 .../CodeAnalysisService_NavigateTo.cs         |  5 ++--
 .../CodeAnalysisService_SymbolFinder.cs       |  9 ++++---
 .../CodeAnalysisService_TodoComments.cs       |  4 +--
 .../RemoteSymbolSearchUpdateEngine.cs         |  7 ++---
 24 files changed, 102 insertions(+), 79 deletions(-)

diff --git a/src/EditorFeatures/CSharpTest/AddUsing/AddUsingTests_NuGet.cs b/src/EditorFeatures/CSharpTest/AddUsing/AddUsingTests_NuGet.cs
index 3ae80b428f51f..1bd614d61dfd5 100644
--- a/src/EditorFeatures/CSharpTest/AddUsing/AddUsingTests_NuGet.cs
+++ b/src/EditorFeatures/CSharpTest/AddUsing/AddUsingTests_NuGet.cs
@@ -257,7 +257,7 @@ public async Task TestFailedInstallRollsBackFile()
             installerServiceMock.Verify();
         }
 
-        private Task<ImmutableArray<PackageWithTypeResult>> CreateSearchResult(
+        private Task<IReadOnlyList<PackageWithTypeResult>> CreateSearchResult(
             string packageName, string typeName, ImmutableArray<string> containingNamespaceNames)
         {
             return CreateSearchResult(new PackageWithTypeResult(
@@ -265,8 +265,8 @@ public async Task TestFailedInstallRollsBackFile()
                 rank: 0, containingNamespaceNames: containingNamespaceNames));
         }
 
-        private Task<ImmutableArray<PackageWithTypeResult>> CreateSearchResult(params PackageWithTypeResult[] results)
-            => Task.FromResult(ImmutableArray.Create(results));
+        private Task<IReadOnlyList<PackageWithTypeResult>> CreateSearchResult(params PackageWithTypeResult[] results)
+            => Task.FromResult<IReadOnlyList<PackageWithTypeResult>>(ImmutableArray.Create(results));
 
         private ImmutableArray<string> CreateNameParts(params string[] parts) => parts.ToImmutableArray();
     }
diff --git a/src/EditorFeatures/Core/Implementation/TodoComment/TodoCommentIncrementalAnalyzer.cs b/src/EditorFeatures/Core/Implementation/TodoComment/TodoCommentIncrementalAnalyzer.cs
index eb19bbe0da2f7..86611f7f28087 100644
--- a/src/EditorFeatures/Core/Implementation/TodoComment/TodoCommentIncrementalAnalyzer.cs
+++ b/src/EditorFeatures/Core/Implementation/TodoComment/TodoCommentIncrementalAnalyzer.cs
@@ -87,19 +87,19 @@ public async Task AnalyzeSyntaxAsync(Document document, InvocationReasons reason
             }
         }
 
-        private async Task<IList<TodoComment>> GetTodoCommentsAsync(Document document, ImmutableArray<TodoCommentDescriptor> tokens, CancellationToken cancellationToken)
+        private async Task<IReadOnlyList<TodoComment>> GetTodoCommentsAsync(Document document, IReadOnlyList<TodoCommentDescriptor> tokens, CancellationToken cancellationToken)
         {
             var service = document.GetLanguageService<ITodoCommentService>();
             if (service == null)
             {
                 // no inproc support
-                return SpecializedCollections.EmptyList<TodoComment>();
+                return SpecializedCollections.EmptyReadOnlyList<TodoComment>();
             }
 
             return await service.GetTodoCommentsAsync(document, tokens, cancellationToken).ConfigureAwait(false);
         }
 
-        private async Task<ImmutableArray<TodoItem>> CreateItemsAsync(Document document, IList<TodoComment> comments, CancellationToken cancellationToken)
+        private async Task<ImmutableArray<TodoItem>> CreateItemsAsync(Document document, IReadOnlyList<TodoComment> comments, CancellationToken cancellationToken)
         {
             var items = ImmutableArray.CreateBuilder<TodoItem>();
             if (comments != null)
diff --git a/src/EditorFeatures/VisualBasicTest/Diagnostics/AddImport/AddImportTests_NuGet.vb b/src/EditorFeatures/VisualBasicTest/Diagnostics/AddImport/AddImportTests_NuGet.vb
index 9ff4ceb54e975..b2fb56157de3f 100644
--- a/src/EditorFeatures/VisualBasicTest/Diagnostics/AddImport/AddImportTests_NuGet.vb
+++ b/src/EditorFeatures/VisualBasicTest/Diagnostics/AddImport/AddImportTests_NuGet.vb
@@ -239,7 +239,7 @@ End Class", fixProviderData:=New ProviderData(installerServiceMock.Object, packa
             installerServiceMock.Verify()
         End Function
 
-        Private Function CreateSearchResult(packageName As String, typeName As String, nameParts As ImmutableArray(Of String)) As Task(Of ImmutableArray(Of PackageWithTypeResult))
+        Private Function CreateSearchResult(packageName As String, typeName As String, nameParts As ImmutableArray(Of String)) As Task(Of IReadOnlyList(Of PackageWithTypeResult))
             Return CreateSearchResult(New PackageWithTypeResult(
                 packageName:=packageName,
                 typeName:=typeName,
@@ -248,8 +248,8 @@ End Class", fixProviderData:=New ProviderData(installerServiceMock.Object, packa
                 containingNamespaceNames:=nameParts))
         End Function
 
-        Private Function CreateSearchResult(ParamArray results As PackageWithTypeResult()) As Task(Of ImmutableArray(Of PackageWithTypeResult))
-            Return Task.FromResult(ImmutableArray.Create(results))
+        Private Function CreateSearchResult(ParamArray results As PackageWithTypeResult()) As Task(Of IReadOnlyList(Of PackageWithTypeResult))
+            Return Task.FromResult(Of IReadOnlyList(Of PackageWithTypeResult))(ImmutableArray.Create(results))
         End Function
 
         Private Function CreateNameParts(ParamArray parts As String()) As ImmutableArray(Of String)
diff --git a/src/Features/CSharp/Portable/TodoComments/CSharpTodoCommentIncrementalAnalyzerProvider.cs b/src/Features/CSharp/Portable/TodoComments/CSharpTodoCommentIncrementalAnalyzerProvider.cs
index 2ae1686fea383..6ec91af8f23bb 100644
--- a/src/Features/CSharp/Portable/TodoComments/CSharpTodoCommentIncrementalAnalyzerProvider.cs
+++ b/src/Features/CSharp/Portable/TodoComments/CSharpTodoCommentIncrementalAnalyzerProvider.cs
@@ -28,7 +28,7 @@ public CSharpTodoCommentService(Workspace workspace) : base(workspace)
         {
         }
 
-        protected override void AppendTodoComments(ImmutableArray<TodoCommentDescriptor> commentDescriptors, SyntacticDocument document, SyntaxTrivia trivia, List<TodoComment> todoList)
+        protected override void AppendTodoComments(IReadOnlyList<TodoCommentDescriptor> commentDescriptors, SyntacticDocument document, SyntaxTrivia trivia, List<TodoComment> todoList)
         {
             if (PreprocessorHasComment(trivia))
             {
diff --git a/src/Features/Core/Portable/AddImport/Remote/AbstractAddImportFeatureService_Remote.cs b/src/Features/Core/Portable/AddImport/Remote/AbstractAddImportFeatureService_Remote.cs
index 061faee76876d..3a236ddf729c0 100644
--- a/src/Features/Core/Portable/AddImport/Remote/AbstractAddImportFeatureService_Remote.cs
+++ b/src/Features/Core/Portable/AddImport/Remote/AbstractAddImportFeatureService_Remote.cs
@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
 using System;
+using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Threading;
 using System.Threading.Tasks;
@@ -39,21 +40,21 @@ public Task UpdateContinuouslyAsync(string sourceName, string localSettingsDirec
                 throw new NotImplementedException();
             }
 
-            public Task<ImmutableArray<PackageWithTypeResult>> FindPackagesWithTypeAsync(
+            public Task<IReadOnlyList<PackageWithTypeResult>> FindPackagesWithTypeAsync(
                 string source, string name, int arity, CancellationToken cancellationToken)
             {
                 return _symbolSearchService.FindPackagesWithTypeAsync(
                     source, name, arity, cancellationToken);
             }
 
-            public Task<ImmutableArray<PackageWithAssemblyResult>> FindPackagesWithAssemblyAsync(
+            public Task<IReadOnlyList<PackageWithAssemblyResult>> FindPackagesWithAssemblyAsync(
                 string source, string name, CancellationToken cancellationToken)
             {
                 return _symbolSearchService.FindPackagesWithAssemblyAsync(
                     source, name, cancellationToken);
             }
 
-            public Task<ImmutableArray<ReferenceAssemblyWithTypeResult>> FindReferenceAssembliesWithTypeAsync(
+            public Task<IReadOnlyList<ReferenceAssemblyWithTypeResult>> FindReferenceAssembliesWithTypeAsync(
                 string name, int arity, CancellationToken cancellationToken)
             {
                 return _symbolSearchService.FindReferenceAssembliesWithTypeAsync(
diff --git a/src/Features/Core/Portable/AddImport/Remote/IRemoteAddImportFeatureService.cs b/src/Features/Core/Portable/AddImport/Remote/IRemoteAddImportFeatureService.cs
index 550c375c35fcc..f1d93472c9f31 100644
--- a/src/Features/Core/Portable/AddImport/Remote/IRemoteAddImportFeatureService.cs
+++ b/src/Features/Core/Portable/AddImport/Remote/IRemoteAddImportFeatureService.cs
@@ -1,5 +1,6 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
+using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Threading;
 using System.Threading.Tasks;
@@ -10,8 +11,8 @@ namespace Microsoft.CodeAnalysis.AddImport
 {
     internal interface IRemoteAddImportFeatureService
     {
-        Task<ImmutableArray<AddImportFixData>> GetFixesAsync(
+        Task<IReadOnlyList<AddImportFixData>> GetFixesAsync(
             DocumentId documentId, TextSpan span, string diagnosticId, bool placeSystemNamespaceFirst,
-            bool searchReferenceAssemblies, ImmutableArray<PackageSource> packageSources, CancellationToken cancellationToken);
+            bool searchReferenceAssemblies, IReadOnlyList<PackageSource> packageSources, CancellationToken cancellationToken);
     }
 }
diff --git a/src/Features/Core/Portable/AddImport/SymbolReferenceFinder_PackageAssemblySearch.cs b/src/Features/Core/Portable/AddImport/SymbolReferenceFinder_PackageAssemblySearch.cs
index 70fcebdd37e76..a2bc71f0cd822 100644
--- a/src/Features/Core/Portable/AddImport/SymbolReferenceFinder_PackageAssemblySearch.cs
+++ b/src/Features/Core/Portable/AddImport/SymbolReferenceFinder_PackageAssemblySearch.cs
@@ -90,7 +90,7 @@ private partial class SymbolReferenceFinder
                 cancellationToken.ThrowIfCancellationRequested();
                 var results = await _symbolSearchService.FindReferenceAssembliesWithTypeAsync(
                     name, arity, cancellationToken).ConfigureAwait(false);
-                if (results.IsDefault)
+                if (results == null)
                 {
                     return;
                 }
@@ -121,7 +121,7 @@ private partial class SymbolReferenceFinder
                 cancellationToken.ThrowIfCancellationRequested();
                 var results = await _symbolSearchService.FindPackagesWithTypeAsync(
                     source.Name, name, arity, cancellationToken).ConfigureAwait(false);
-                if (results.IsDefault)
+                if (results == null)
                 {
                     return;
                 }
diff --git a/src/Features/Core/Portable/DocumentHighlighting/IRemoteDocumentHighlights.cs b/src/Features/Core/Portable/DocumentHighlighting/IRemoteDocumentHighlights.cs
index 43cd320c46565..4078b4082413a 100644
--- a/src/Features/Core/Portable/DocumentHighlighting/IRemoteDocumentHighlights.cs
+++ b/src/Features/Core/Portable/DocumentHighlighting/IRemoteDocumentHighlights.cs
@@ -1,5 +1,6 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
+using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Linq;
 using System.Threading;
@@ -9,17 +10,17 @@ namespace Microsoft.CodeAnalysis.DocumentHighlighting
 {
     internal interface IRemoteDocumentHighlights
     {
-        Task<ImmutableArray<SerializableDocumentHighlights>> GetDocumentHighlightsAsync(
+        Task<IReadOnlyList<SerializableDocumentHighlights>> GetDocumentHighlightsAsync(
             DocumentId documentId, int position, DocumentId[] documentIdsToSearch, CancellationToken cancellationToken);
     }
 
     internal struct SerializableDocumentHighlights
     {
         public DocumentId DocumentId;
-        public ImmutableArray<HighlightSpan> HighlightSpans;
+        public IReadOnlyList<HighlightSpan> HighlightSpans;
 
         public DocumentHighlights Rehydrate(Solution solution)
-            => new DocumentHighlights(solution.GetDocument(DocumentId), HighlightSpans);
+            => new DocumentHighlights(solution.GetDocument(DocumentId), HighlightSpans.ToImmutableArray());
 
         public static SerializableDocumentHighlights Dehydrate(DocumentHighlights highlights)
             => new SerializableDocumentHighlights
diff --git a/src/Features/Core/Portable/NavigateTo/IRemoteNavigateToSearchService.cs b/src/Features/Core/Portable/NavigateTo/IRemoteNavigateToSearchService.cs
index 936a91a04fce4..cf1089e29eb96 100644
--- a/src/Features/Core/Portable/NavigateTo/IRemoteNavigateToSearchService.cs
+++ b/src/Features/Core/Portable/NavigateTo/IRemoteNavigateToSearchService.cs
@@ -1,5 +1,6 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
+using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Threading;
 using System.Threading.Tasks;
@@ -9,7 +10,7 @@ namespace Microsoft.CodeAnalysis.NavigateTo
 {
     internal interface IRemoteNavigateToSearchService
     {
-        Task<ImmutableArray<SerializableNavigateToSearchResult>> SearchDocumentAsync(DocumentId documentId, string searchPattern, CancellationToken cancellationToken);
-        Task<ImmutableArray<SerializableNavigateToSearchResult>> SearchProjectAsync(ProjectId projectId, string searchPattern, CancellationToken cancellationToken);
+        Task<IReadOnlyList<SerializableNavigateToSearchResult>> SearchDocumentAsync(DocumentId documentId, string searchPattern, CancellationToken cancellationToken);
+        Task<IReadOnlyList<SerializableNavigateToSearchResult>> SearchProjectAsync(ProjectId projectId, string searchPattern, CancellationToken cancellationToken);
     }
 }
diff --git a/src/Features/Core/Portable/TodoComments/AbstractTodoCommentService.cs b/src/Features/Core/Portable/TodoComments/AbstractTodoCommentService.cs
index c39525a3e5dec..a45cef7e5f114 100644
--- a/src/Features/Core/Portable/TodoComments/AbstractTodoCommentService.cs
+++ b/src/Features/Core/Portable/TodoComments/AbstractTodoCommentService.cs
@@ -36,9 +36,9 @@ protected AbstractTodoCommentService(Workspace workspace)
 
         protected abstract string GetNormalizedText(string message);
         protected abstract int GetCommentStartingIndex(string message);
-        protected abstract void AppendTodoComments(ImmutableArray<TodoCommentDescriptor> commentDescriptors, SyntacticDocument document, SyntaxTrivia trivia, List<TodoComment> todoList);
+        protected abstract void AppendTodoComments(IReadOnlyList<TodoCommentDescriptor> commentDescriptors, SyntacticDocument document, SyntaxTrivia trivia, List<TodoComment> todoList);
 
-        public async Task<IList<TodoComment>> GetTodoCommentsAsync(Document document, ImmutableArray<TodoCommentDescriptor> commentDescriptors, CancellationToken cancellationToken)
+        public async Task<IReadOnlyList<TodoComment>> GetTodoCommentsAsync(Document document, IReadOnlyList<TodoCommentDescriptor> commentDescriptors, CancellationToken cancellationToken)
         {
             // make sure given input is right one
             Contract.ThrowIfFalse(_workspace == document.Project.Solution.Workspace);
@@ -58,17 +58,17 @@ public async Task<IList<TodoComment>> GetTodoCommentsAsync(Document document, Im
             return await GetTodoCommentsInCurrentProcessAsync(document, commentDescriptors, cancellationToken).ConfigureAwait(false);
         }
 
-        private async Task<IList<TodoComment>> GetTodoCommentsInRemoteHostAsync(
-            RemoteHostClient client, Document document, ImmutableArray<TodoCommentDescriptor> commentDescriptors, CancellationToken cancellationToken)
+        private async Task<IReadOnlyList<TodoComment>> GetTodoCommentsInRemoteHostAsync(
+            RemoteHostClient client, Document document, IReadOnlyList<TodoCommentDescriptor> commentDescriptors, CancellationToken cancellationToken)
         {
             var keepAliveSession = await TryGetKeepAliveSessionAsync(client, cancellationToken).ConfigureAwait(false);
 
-            var result = await keepAliveSession.TryInvokeAsync<IList<TodoComment>>(
+            var result = await keepAliveSession.TryInvokeAsync<IReadOnlyList<TodoComment>>(
                 nameof(IRemoteTodoCommentService.GetTodoCommentsAsync),
                 document.Project.Solution,
                 new object[] { document.Id, commentDescriptors }, cancellationToken).ConfigureAwait(false);
 
-            return result ?? SpecializedCollections.EmptyList<TodoComment>();
+            return result ?? SpecializedCollections.EmptyReadOnlyList<TodoComment>();
         }
 
         private async Task<KeepAliveSession> TryGetKeepAliveSessionAsync(RemoteHostClient client, CancellationToken cancellationToken)
@@ -84,8 +84,8 @@ private async Task<KeepAliveSession> TryGetKeepAliveSessionAsync(RemoteHostClien
             }
         }
 
-        private async Task<IList<TodoComment>> GetTodoCommentsInCurrentProcessAsync(
-            Document document, ImmutableArray<TodoCommentDescriptor> commentDescriptors, CancellationToken cancellationToken)
+        private async Task<IReadOnlyList<TodoComment>> GetTodoCommentsInCurrentProcessAsync(
+            Document document, IReadOnlyList<TodoCommentDescriptor> commentDescriptors, CancellationToken cancellationToken)
         {
             cancellationToken.ThrowIfCancellationRequested();
 
@@ -115,7 +115,7 @@ private bool ContainsComments(SyntaxTrivia trivia)
             return PreprocessorHasComment(trivia) || IsSingleLineComment(trivia) || IsMultilineComment(trivia);
         }
 
-        protected void AppendTodoCommentInfoFromSingleLine(ImmutableArray<TodoCommentDescriptor> commentDescriptors, SyntacticDocument document, string message, int start, List<TodoComment> todoList)
+        protected void AppendTodoCommentInfoFromSingleLine(IReadOnlyList<TodoCommentDescriptor> commentDescriptors, SyntacticDocument document, string message, int start, List<TodoComment> todoList)
         {
             var index = GetCommentStartingIndex(message);
             if (index >= message.Length)
@@ -147,7 +147,7 @@ protected void AppendTodoCommentInfoFromSingleLine(ImmutableArray<TodoCommentDes
             }
         }
 
-        protected void ProcessMultilineComment(ImmutableArray<TodoCommentDescriptor> commentDescriptors, SyntacticDocument document, SyntaxTrivia trivia, int postfixLength, List<TodoComment> todoList)
+        protected void ProcessMultilineComment(IReadOnlyList<TodoCommentDescriptor> commentDescriptors, SyntacticDocument document, SyntaxTrivia trivia, int postfixLength, List<TodoComment> todoList)
         {
             // this is okay since we know it is already alive
             var text = document.Text;
diff --git a/src/Features/Core/Portable/TodoComments/IRemoteTodoCommentService.cs b/src/Features/Core/Portable/TodoComments/IRemoteTodoCommentService.cs
index 5fd991c6d5718..c65172d3f1032 100644
--- a/src/Features/Core/Portable/TodoComments/IRemoteTodoCommentService.cs
+++ b/src/Features/Core/Portable/TodoComments/IRemoteTodoCommentService.cs
@@ -13,6 +13,6 @@ namespace Microsoft.CodeAnalysis.TodoComments
     /// </summary>
     internal interface IRemoteTodoCommentService
     {
-        Task<IList<TodoComment>> GetTodoCommentsAsync(PinnedSolutionInfo solutionInfo, DocumentId documentId, ImmutableArray<TodoCommentDescriptor> commentDescriptors, CancellationToken cancellationToken);
+        Task<IReadOnlyList<TodoComment>> GetTodoCommentsAsync(PinnedSolutionInfo solutionInfo, DocumentId documentId, IReadOnlyList<TodoCommentDescriptor> commentDescriptors, CancellationToken cancellationToken);
     }
 }
diff --git a/src/Features/Core/Portable/TodoComments/ITodoCommentService.cs b/src/Features/Core/Portable/TodoComments/ITodoCommentService.cs
index b1407ad36478c..3a378b5b409c6 100644
--- a/src/Features/Core/Portable/TodoComments/ITodoCommentService.cs
+++ b/src/Features/Core/Portable/TodoComments/ITodoCommentService.cs
@@ -42,6 +42,6 @@ public TodoComment(TodoCommentDescriptor descriptor, string message, int positio
 
     internal interface ITodoCommentService : ILanguageService
     {
-        Task<IList<TodoComment>> GetTodoCommentsAsync(Document document, ImmutableArray<TodoCommentDescriptor> commentDescriptors, CancellationToken cancellationToken);
+        Task<IReadOnlyList<TodoComment>> GetTodoCommentsAsync(Document document, IReadOnlyList<TodoCommentDescriptor> commentDescriptors, CancellationToken cancellationToken);
     }
 }
diff --git a/src/Features/VisualBasic/Portable/TodoComments/BasicTodoCommentIncrementalAnalyzerProvider.vb b/src/Features/VisualBasic/Portable/TodoComments/BasicTodoCommentIncrementalAnalyzerProvider.vb
index 012c20743e19e..dbcdfe3003f11 100644
--- a/src/Features/VisualBasic/Portable/TodoComments/BasicTodoCommentIncrementalAnalyzerProvider.vb
+++ b/src/Features/VisualBasic/Portable/TodoComments/BasicTodoCommentIncrementalAnalyzerProvider.vb
@@ -25,7 +25,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.TodoComments
             MyBase.New(workspace)
         End Sub
 
-        Protected Overrides Sub AppendTodoComments(commentDescriptors As ImmutableArray(Of TodoCommentDescriptor), document As SyntacticDocument, trivia As SyntaxTrivia, todoList As List(Of TodoComment))
+        Protected Overrides Sub AppendTodoComments(commentDescriptors As IReadOnlyList(Of TodoCommentDescriptor), document As SyntacticDocument, trivia As SyntaxTrivia, todoList As List(Of TodoComment))
             If PreprocessorHasComment(trivia) Then
                 Dim commentTrivia = trivia.GetStructure().DescendantTrivia().First(Function(t) t.RawKind = SyntaxKind.CommentTrivia)
 
diff --git a/src/VisualStudio/Core/Def/SymbolSearch/VisualStudioSymbolSearchService.cs b/src/VisualStudio/Core/Def/SymbolSearch/VisualStudioSymbolSearchService.cs
index 49ca30337690d..6b7f9d79befc6 100644
--- a/src/VisualStudio/Core/Def/SymbolSearch/VisualStudioSymbolSearchService.cs
+++ b/src/VisualStudio/Core/Def/SymbolSearch/VisualStudioSymbolSearchService.cs
@@ -108,7 +108,7 @@ private async Task UpdateSourceInBackgroundAsync(string sourceName)
             await engine.UpdateContinuouslyAsync(sourceName, _localSettingsDirectory).ConfigureAwait(false);
         }
 
-        public async Task<ImmutableArray<PackageWithTypeResult>> FindPackagesWithTypeAsync(
+        public async Task<IReadOnlyList<PackageWithTypeResult>> FindPackagesWithTypeAsync(
             string source, string name, int arity, CancellationToken cancellationToken)
         {
             var engine = await GetEngine(cancellationToken).ConfigureAwait(false);
@@ -118,7 +118,7 @@ private async Task UpdateSourceInBackgroundAsync(string sourceName)
             return FilterAndOrderPackages(allPackagesWithType);
         }
 
-        public async Task<ImmutableArray<PackageWithAssemblyResult>> FindPackagesWithAssemblyAsync(
+        public async Task<IReadOnlyList<PackageWithAssemblyResult>> FindPackagesWithAssemblyAsync(
             string source, string assemblyName, CancellationToken cancellationToken)
         {
             var engine = await GetEngine(cancellationToken).ConfigureAwait(false);
@@ -170,7 +170,7 @@ private async Task UpdateSourceInBackgroundAsync(string sourceName)
             return result.ToImmutableAndFree();
         }
 
-        public async Task<ImmutableArray<ReferenceAssemblyWithTypeResult>> FindReferenceAssembliesWithTypeAsync(
+        public async Task<IReadOnlyList<ReferenceAssemblyWithTypeResult>> FindReferenceAssembliesWithTypeAsync(
             string name, int arity, CancellationToken cancellationToken)
         {
             var engine = await GetEngine(cancellationToken).ConfigureAwait(false);
diff --git a/src/Workspaces/Core/Portable/FindSymbols/IRemoteSymbolFinder.cs b/src/Workspaces/Core/Portable/FindSymbols/IRemoteSymbolFinder.cs
index ed8a2c8e000ea..c676d62ab248e 100644
--- a/src/Workspaces/Core/Portable/FindSymbols/IRemoteSymbolFinder.cs
+++ b/src/Workspaces/Core/Portable/FindSymbols/IRemoteSymbolFinder.cs
@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
 using System;
+using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Threading;
 using System.Threading.Tasks;
@@ -13,16 +14,16 @@ internal interface IRemoteSymbolFinder
         Task FindReferencesAsync(SerializableSymbolAndProjectId symbolAndProjectIdArg, DocumentId[] documentArgs, CancellationToken cancellationToken);
         Task FindLiteralReferencesAsync(object value, TypeCode typeCode, CancellationToken cancellationToken);
 
-        Task<ImmutableArray<SerializableSymbolAndProjectId>> FindAllDeclarationsWithNormalQueryAsync(
+        Task<IReadOnlyList<SerializableSymbolAndProjectId>> FindAllDeclarationsWithNormalQueryAsync(
             ProjectId projectId, string name, SearchKind searchKind, SymbolFilter criteria, CancellationToken cancellationToken);
 
-        Task<ImmutableArray<SerializableSymbolAndProjectId>> FindSolutionSourceDeclarationsWithNormalQueryAsync(
+        Task<IReadOnlyList<SerializableSymbolAndProjectId>> FindSolutionSourceDeclarationsWithNormalQueryAsync(
             string name, bool ignoreCase, SymbolFilter criteria, CancellationToken cancellationToken);
 
-        Task<ImmutableArray<SerializableSymbolAndProjectId>> FindProjectSourceDeclarationsWithNormalQueryAsync(
+        Task<IReadOnlyList<SerializableSymbolAndProjectId>> FindProjectSourceDeclarationsWithNormalQueryAsync(
             ProjectId projectId, string name, bool ignoreCase, SymbolFilter criteria, CancellationToken cancellationToken);
 
-        Task<ImmutableArray<SerializableSymbolAndProjectId>> FindProjectSourceDeclarationsWithPatternAsync(
+        Task<IReadOnlyList<SerializableSymbolAndProjectId>> FindProjectSourceDeclarationsWithPatternAsync(
             ProjectId projectId, string pattern, SymbolFilter criteria, CancellationToken cancellationToken);
     }
 }
diff --git a/src/Workspaces/Core/Portable/SymbolSearch/IRemoteSymbolSearchUpdateEngine.cs b/src/Workspaces/Core/Portable/SymbolSearch/IRemoteSymbolSearchUpdateEngine.cs
index a5bd4254b4b18..f784a9b343622 100644
--- a/src/Workspaces/Core/Portable/SymbolSearch/IRemoteSymbolSearchUpdateEngine.cs
+++ b/src/Workspaces/Core/Portable/SymbolSearch/IRemoteSymbolSearchUpdateEngine.cs
@@ -1,5 +1,6 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
+using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Threading;
 using System.Threading.Tasks;
@@ -10,8 +11,8 @@ internal interface IRemoteSymbolSearchUpdateEngine
     {
         Task UpdateContinuouslyAsync(string sourceName, string localSettingsDirectory);
 
-        Task<ImmutableArray<PackageWithTypeResult>> FindPackagesWithTypeAsync(string source, string name, int arity, CancellationToken cancellationToken);
-        Task<ImmutableArray<PackageWithAssemblyResult>> FindPackagesWithAssemblyAsync(string source, string name, CancellationToken cancellationToken);
-        Task<ImmutableArray<ReferenceAssemblyWithTypeResult>> FindReferenceAssembliesWithTypeAsync(string name, int arity, CancellationToken cancellationToken);
+        Task<IReadOnlyList<PackageWithTypeResult>> FindPackagesWithTypeAsync(string source, string name, int arity, CancellationToken cancellationToken);
+        Task<IReadOnlyList<PackageWithAssemblyResult>> FindPackagesWithAssemblyAsync(string source, string name, CancellationToken cancellationToken);
+        Task<IReadOnlyList<ReferenceAssemblyWithTypeResult>> FindReferenceAssembliesWithTypeAsync(string name, int arity, CancellationToken cancellationToken);
     }
 }
diff --git a/src/Workspaces/Core/Portable/SymbolSearch/ISymbolSearchService.cs b/src/Workspaces/Core/Portable/SymbolSearch/ISymbolSearchService.cs
index 1be1614d5b67f..9a7725e331f58 100644
--- a/src/Workspaces/Core/Portable/SymbolSearch/ISymbolSearchService.cs
+++ b/src/Workspaces/Core/Portable/SymbolSearch/ISymbolSearchService.cs
@@ -23,7 +23,7 @@ internal interface ISymbolSearchService : IWorkspaceService
         /// Implementations should return results in order from best to worst (from their
         /// perspective).
         /// </summary>
-        Task<ImmutableArray<PackageWithTypeResult>> FindPackagesWithTypeAsync(
+        Task<IReadOnlyList<PackageWithTypeResult>> FindPackagesWithTypeAsync(
             string source, string name, int arity, CancellationToken cancellationToken);
 
         /// <summary>
@@ -34,7 +34,7 @@ internal interface ISymbolSearchService : IWorkspaceService
         /// Implementations should return results in order from best to worst (from their
         /// perspective).
         /// </summary>
-        Task<ImmutableArray<PackageWithAssemblyResult>> FindPackagesWithAssemblyAsync(
+        Task<IReadOnlyList<PackageWithAssemblyResult>> FindPackagesWithAssemblyAsync(
             string source, string assemblyName, CancellationToken cancellationToken);
 
         /// <summary>
@@ -46,7 +46,7 @@ internal interface ISymbolSearchService : IWorkspaceService
         /// Implementations should return results in order from best to worst (from their
         /// perspective).
         /// </summary>
-        Task<ImmutableArray<ReferenceAssemblyWithTypeResult>> FindReferenceAssembliesWithTypeAsync(
+        Task<IReadOnlyList<ReferenceAssemblyWithTypeResult>> FindReferenceAssembliesWithTypeAsync(
             string name, int arity, CancellationToken cancellationToken);
     }
 
@@ -64,7 +64,7 @@ protected PackageResult(string packageName, int rank)
 
     internal class PackageWithTypeResult : PackageResult
     {
-        public readonly ImmutableArray<string> ContainingNamespaceNames;
+        public readonly IReadOnlyList<string> ContainingNamespaceNames;
         public readonly string TypeName;
         public readonly string Version;
 
@@ -73,7 +73,7 @@ internal class PackageWithTypeResult : PackageResult
             string typeName,
             string version,
             int rank,
-            ImmutableArray<string> containingNamespaceNames)
+            IReadOnlyList<string> containingNamespaceNames)
             : base(packageName, rank)
         {
             TypeName = typeName;
@@ -118,14 +118,14 @@ public int CompareTo(PackageWithAssemblyResult other)
 
     internal class ReferenceAssemblyWithTypeResult
     {
-        public readonly ImmutableArray<string> ContainingNamespaceNames;
+        public readonly IReadOnlyList<string> ContainingNamespaceNames;
         public readonly string AssemblyName;
         public readonly string TypeName;
 
         public ReferenceAssemblyWithTypeResult(
             string assemblyName,
             string typeName,
-            ImmutableArray<string> containingNamespaceNames)
+            IReadOnlyList<string> containingNamespaceNames)
         {
             AssemblyName = assemblyName;
             TypeName = typeName;
@@ -136,22 +136,22 @@ internal class ReferenceAssemblyWithTypeResult
     [ExportWorkspaceService(typeof(ISymbolSearchService)), Shared]
     internal class DefaultSymbolSearchService : ISymbolSearchService
     {
-        public Task<ImmutableArray<PackageWithTypeResult>> FindPackagesWithTypeAsync(
+        public Task<IReadOnlyList<PackageWithTypeResult>> FindPackagesWithTypeAsync(
             string source, string name, int arity, CancellationToken cancellationToken)
         {
-            return SpecializedTasks.EmptyImmutableArray<PackageWithTypeResult>();
+            return SpecializedTasks.EmptyReadOnlyList<PackageWithTypeResult>();
         }
 
-        public Task<ImmutableArray<PackageWithAssemblyResult>> FindPackagesWithAssemblyAsync(
+        public Task<IReadOnlyList<PackageWithAssemblyResult>> FindPackagesWithAssemblyAsync(
             string source, string assemblyName, CancellationToken cancellationToken)
         {
-            return SpecializedTasks.EmptyImmutableArray<PackageWithAssemblyResult>();
+            return SpecializedTasks.EmptyReadOnlyList<PackageWithAssemblyResult>();
         }
 
-        public Task<ImmutableArray<ReferenceAssemblyWithTypeResult>> FindReferenceAssembliesWithTypeAsync(
+        public Task<IReadOnlyList<ReferenceAssemblyWithTypeResult>> FindReferenceAssembliesWithTypeAsync(
             string name, int arity, CancellationToken cancellationToken)
         {
-            return SpecializedTasks.EmptyImmutableArray<ReferenceAssemblyWithTypeResult>();
+            return SpecializedTasks.EmptyReadOnlyList<ReferenceAssemblyWithTypeResult>();
         }
     }
 }
diff --git a/src/Workspaces/Core/Portable/Utilities/SpecializedTasks.cs b/src/Workspaces/Core/Portable/Utilities/SpecializedTasks.cs
index 88d1a406467d5..619a83bc7b18f 100644
--- a/src/Workspaces/Core/Portable/Utilities/SpecializedTasks.cs
+++ b/src/Workspaces/Core/Portable/Utilities/SpecializedTasks.cs
@@ -28,6 +28,16 @@ public static Task<T> DefaultOrResult<T>(T value)
             return Task.FromResult(value);
         }
 
+        public static Task<IReadOnlyList<T>> EmptyReadOnlyList<T>()
+        {
+            return Empty<T>.EmptyReadOnlyList;
+        }
+
+        public static Task<IList<T>> EmptyList<T>()
+        {
+            return Empty<T>.EmptyList;
+        }
+
         public static Task<ImmutableArray<T>> EmptyImmutableArray<T>()
         {
             return Empty<T>.EmptyImmutableArray;
@@ -48,6 +58,8 @@ private static class Empty<T>
             public static readonly Task<T> Default = Task.FromResult<T>(default);
             public static readonly Task<IEnumerable<T>> EmptyEnumerable = Task.FromResult<IEnumerable<T>>(SpecializedCollections.EmptyEnumerable<T>());
             public static readonly Task<ImmutableArray<T>> EmptyImmutableArray = Task.FromResult(ImmutableArray<T>.Empty);
+            public static readonly Task<IList<T>> EmptyList = Task.FromResult(SpecializedCollections.EmptyList<T>());
+            public static readonly Task<IReadOnlyList<T>> EmptyReadOnlyList = Task.FromResult(SpecializedCollections.EmptyReadOnlyList<T>());
         }
 
         private static class FromResultCache<T> where T : class
diff --git a/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_AddImport.cs b/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_AddImport.cs
index c6b34cfa47927..004088f8b1ecd 100644
--- a/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_AddImport.cs
+++ b/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_AddImport.cs
@@ -1,5 +1,6 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
+using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Threading;
 using System.Threading.Tasks;
@@ -13,9 +14,9 @@ namespace Microsoft.CodeAnalysis.Remote
 {
     internal partial class CodeAnalysisService : IRemoteAddImportFeatureService
     {
-        public async Task<ImmutableArray<AddImportFixData>> GetFixesAsync(
+        public async Task<IReadOnlyList<AddImportFixData>> GetFixesAsync(
             DocumentId documentId, TextSpan span, string diagnosticId, bool placeSystemNamespaceFirst,
-            bool searchReferenceAssemblies, ImmutableArray<PackageSource> packageSources, CancellationToken cancellationToken)
+            bool searchReferenceAssemblies, IReadOnlyList<PackageSource> packageSources, CancellationToken cancellationToken)
         {
             using (UserOperationBooster.Boost())
             {
@@ -29,7 +30,7 @@ internal partial class CodeAnalysisService : IRemoteAddImportFeatureService
                 var result = await service.GetFixesAsync(
                     document, span, diagnosticId, placeSystemNamespaceFirst,
                     symbolSearchService, searchReferenceAssemblies,
-                    packageSources, cancellationToken).ConfigureAwait(false);
+                    packageSources.ToImmutableArray(), cancellationToken).ConfigureAwait(false);
 
                 return result;
             }
@@ -54,28 +55,28 @@ public SymbolSearchService(CodeAnalysisService codeAnalysisService)
                 this.codeAnalysisService = codeAnalysisService;
             }
 
-            public async Task<ImmutableArray<PackageWithTypeResult>> FindPackagesWithTypeAsync(
+            public async Task<IReadOnlyList<PackageWithTypeResult>> FindPackagesWithTypeAsync(
                 string source, string name, int arity, CancellationToken cancellationToken)
             {
-                var result = await codeAnalysisService.Rpc.InvokeAsync<ImmutableArray<PackageWithTypeResult>>(
+                var result = await codeAnalysisService.Rpc.InvokeAsync<IReadOnlyList<PackageWithTypeResult>>(
                     nameof(FindPackagesWithTypeAsync), source, name, arity).ConfigureAwait(false);
 
                 return result;
             }
 
-            public async Task<ImmutableArray<PackageWithAssemblyResult>> FindPackagesWithAssemblyAsync(
+            public async Task<IReadOnlyList<PackageWithAssemblyResult>> FindPackagesWithAssemblyAsync(
                 string source, string assemblyName, CancellationToken cancellationToken)
             {
-                var result = await codeAnalysisService.Rpc.InvokeAsync<ImmutableArray<PackageWithAssemblyResult>>(
+                var result = await codeAnalysisService.Rpc.InvokeAsync<IReadOnlyList<PackageWithAssemblyResult>>(
                     nameof(FindPackagesWithAssemblyAsync), source, assemblyName).ConfigureAwait(false);
 
                 return result;
             }
 
-            public async Task<ImmutableArray<ReferenceAssemblyWithTypeResult>> FindReferenceAssembliesWithTypeAsync(
+            public async Task<IReadOnlyList<ReferenceAssemblyWithTypeResult>> FindReferenceAssembliesWithTypeAsync(
                 string name, int arity, CancellationToken cancellationToken)
             {
-                var result = await codeAnalysisService.Rpc.InvokeAsync<ImmutableArray<ReferenceAssemblyWithTypeResult>>(
+                var result = await codeAnalysisService.Rpc.InvokeAsync<IReadOnlyList<ReferenceAssemblyWithTypeResult>>(
                     nameof(FindReferenceAssembliesWithTypeAsync), name, arity).ConfigureAwait(false);
 
                 return result;
diff --git a/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_DocumentHighlights.cs b/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_DocumentHighlights.cs
index e62228197bbcd..e8af78b445657 100644
--- a/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_DocumentHighlights.cs
+++ b/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_DocumentHighlights.cs
@@ -1,5 +1,6 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
+using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Linq;
 using System.Threading;
@@ -13,7 +14,7 @@ namespace Microsoft.CodeAnalysis.Remote
     // root level service for all Roslyn services
     internal partial class CodeAnalysisService : IRemoteDocumentHighlights
     {
-        public async Task<ImmutableArray<SerializableDocumentHighlights>> GetDocumentHighlightsAsync(
+        public async Task<IReadOnlyList<SerializableDocumentHighlights>> GetDocumentHighlightsAsync(
             DocumentId documentId, int position, DocumentId[] documentIdsToSearch, CancellationToken cancellationToken)
         {
             // NOTE: In projection scenarios, we might get a set of documents to search
diff --git a/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_NavigateTo.cs b/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_NavigateTo.cs
index 96bd6613c5081..346f1714b25d4 100644
--- a/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_NavigateTo.cs
+++ b/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_NavigateTo.cs
@@ -1,5 +1,6 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
+using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Threading;
 using System.Threading.Tasks;
@@ -9,7 +10,7 @@ namespace Microsoft.CodeAnalysis.Remote
 {
     internal partial class CodeAnalysisService : IRemoteNavigateToSearchService
     {
-        public async Task<ImmutableArray<SerializableNavigateToSearchResult>> SearchDocumentAsync(
+        public async Task<IReadOnlyList<SerializableNavigateToSearchResult>> SearchDocumentAsync(
             DocumentId documentId, string searchPattern, CancellationToken cancellationToken)
         {
             using (UserOperationBooster.Boost())
@@ -24,7 +25,7 @@ internal partial class CodeAnalysisService : IRemoteNavigateToSearchService
             }
         }
 
-        public async Task<ImmutableArray<SerializableNavigateToSearchResult>> SearchProjectAsync(
+        public async Task<IReadOnlyList<SerializableNavigateToSearchResult>> SearchProjectAsync(
             ProjectId projectId, string searchPattern, CancellationToken cancellationToken)
         {
             using (UserOperationBooster.Boost())
diff --git a/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_SymbolFinder.cs b/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_SymbolFinder.cs
index a2248cff9c61e..588a34983121d 100644
--- a/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_SymbolFinder.cs
+++ b/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_SymbolFinder.cs
@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
 using System;
+using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Linq;
 using System.Threading;
@@ -59,7 +60,7 @@ public async Task FindLiteralReferencesAsync(object value, TypeCode typeCode, Ca
             }
         }
 
-        public async Task<ImmutableArray<SerializableSymbolAndProjectId>> FindAllDeclarationsWithNormalQueryAsync(
+        public async Task<IReadOnlyList<SerializableSymbolAndProjectId>> FindAllDeclarationsWithNormalQueryAsync(
             ProjectId projectId, string name, SearchKind searchKind, SymbolFilter criteria, CancellationToken cancellationToken)
         {
             using (UserOperationBooster.Boost())
@@ -77,7 +78,7 @@ public async Task FindLiteralReferencesAsync(object value, TypeCode typeCode, Ca
             }
         }
 
-        public async Task<ImmutableArray<SerializableSymbolAndProjectId>> FindSolutionSourceDeclarationsWithNormalQueryAsync(
+        public async Task<IReadOnlyList<SerializableSymbolAndProjectId>> FindSolutionSourceDeclarationsWithNormalQueryAsync(
             string name, bool ignoreCase, SymbolFilter criteria, CancellationToken cancellationToken)
         {
             using (UserOperationBooster.Boost())
@@ -90,7 +91,7 @@ public async Task FindLiteralReferencesAsync(object value, TypeCode typeCode, Ca
             }
         }
 
-        public async Task<ImmutableArray<SerializableSymbolAndProjectId>> FindProjectSourceDeclarationsWithNormalQueryAsync(
+        public async Task<IReadOnlyList<SerializableSymbolAndProjectId>> FindProjectSourceDeclarationsWithNormalQueryAsync(
             ProjectId projectId, string name, bool ignoreCase, SymbolFilter criteria, CancellationToken cancellationToken)
         {
             using (UserOperationBooster.Boost())
@@ -105,7 +106,7 @@ public async Task FindLiteralReferencesAsync(object value, TypeCode typeCode, Ca
             }
         }
 
-        public async Task<ImmutableArray<SerializableSymbolAndProjectId>> FindProjectSourceDeclarationsWithPatternAsync(
+        public async Task<IReadOnlyList<SerializableSymbolAndProjectId>> FindProjectSourceDeclarationsWithPatternAsync(
             ProjectId projectId, string pattern, SymbolFilter criteria, CancellationToken cancellationToken)
         {
             using (UserOperationBooster.Boost())
diff --git a/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_TodoComments.cs b/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_TodoComments.cs
index a9cde5d462b2d..ad4323e5a9261 100644
--- a/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_TodoComments.cs
+++ b/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_TodoComments.cs
@@ -23,7 +23,7 @@ internal partial class CodeAnalysisService : IRemoteTodoCommentService
         /// 
         /// This will be called by ServiceHub/JsonRpc framework
         /// </summary>
-        public async Task<IList<TodoComment>> GetTodoCommentsAsync(PinnedSolutionInfo solutionInfo, DocumentId documentId, ImmutableArray<TodoCommentDescriptor> tokens, CancellationToken cancellationToken)
+        public async Task<IReadOnlyList<TodoComment>> GetTodoCommentsAsync(PinnedSolutionInfo solutionInfo, DocumentId documentId, IReadOnlyList<TodoCommentDescriptor> tokens, CancellationToken cancellationToken)
         {
             using (RoslynLogger.LogBlock(FunctionId.CodeAnalysisService_GetTodoCommentsAsync, documentId.ProjectId.DebugName, cancellationToken))
             {
@@ -37,7 +37,7 @@ public async Task<IList<TodoComment>> GetTodoCommentsAsync(PinnedSolutionInfo so
                     return await service.GetTodoCommentsAsync(document, tokens, cancellationToken).ConfigureAwait(false);
                 }
 
-                return SpecializedCollections.EmptyList<TodoComment>();
+                return SpecializedCollections.EmptyReadOnlyList<TodoComment>();
             }
         }
     }
diff --git a/src/Workspaces/Remote/ServiceHub/Services/RemoteSymbolSearchUpdateEngine.cs b/src/Workspaces/Remote/ServiceHub/Services/RemoteSymbolSearchUpdateEngine.cs
index d424a5c47e2b8..9d94411133f07 100644
--- a/src/Workspaces/Remote/ServiceHub/Services/RemoteSymbolSearchUpdateEngine.cs
+++ b/src/Workspaces/Remote/ServiceHub/Services/RemoteSymbolSearchUpdateEngine.cs
@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
 using System;
+using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.IO;
 using System.Threading;
@@ -28,7 +29,7 @@ public Task UpdateContinuouslyAsync(string sourceName, string localSettingsDirec
             return _updateEngine.UpdateContinuouslyAsync(sourceName, localSettingsDirectory);
         }
 
-        public async Task<ImmutableArray<PackageWithTypeResult>> FindPackagesWithTypeAsync(string source, string name, int arity, CancellationToken cancellationToken)
+        public async Task<IReadOnlyList<PackageWithTypeResult>> FindPackagesWithTypeAsync(string source, string name, int arity, CancellationToken cancellationToken)
         {
             var results = await _updateEngine.FindPackagesWithTypeAsync(
                 source, name, arity, cancellationToken).ConfigureAwait(false);
@@ -36,7 +37,7 @@ public async Task<ImmutableArray<PackageWithTypeResult>> FindPackagesWithTypeAsy
             return results;
         }
 
-        public async Task<ImmutableArray<PackageWithAssemblyResult>> FindPackagesWithAssemblyAsync(string source, string assemblyName, CancellationToken cancellationToken)
+        public async Task<IReadOnlyList<PackageWithAssemblyResult>> FindPackagesWithAssemblyAsync(string source, string assemblyName, CancellationToken cancellationToken)
         {
             var results = await _updateEngine.FindPackagesWithAssemblyAsync(
                 source, assemblyName, cancellationToken).ConfigureAwait(false);
@@ -44,7 +45,7 @@ public async Task<ImmutableArray<PackageWithAssemblyResult>> FindPackagesWithAss
             return results;
         }
 
-        public async Task<ImmutableArray<ReferenceAssemblyWithTypeResult>> FindReferenceAssembliesWithTypeAsync(string name, int arity, CancellationToken cancellationToken)
+        public async Task<IReadOnlyList<ReferenceAssemblyWithTypeResult>> FindReferenceAssembliesWithTypeAsync(string name, int arity, CancellationToken cancellationToken)
         {
             var results = await _updateEngine.FindReferenceAssembliesWithTypeAsync(
                 name, arity, cancellationToken).ConfigureAwait(false);

From 29637c41c4b40828e599f37bbe31fafe3838eb9f Mon Sep 17 00:00:00 2001
From: Heejae Chang <hechang@microsoft.com>
Date: Wed, 9 Aug 2017 12:54:52 -0700
Subject: [PATCH 30/77] moved to IReadOnlyList for designer attribute scanner
 as well

---
 .../DesignerAttributes/IRemoteDesignerAttributeService.cs     | 2 +-
 .../DesignerAttribute/DesignerAttributeIncrementalAnalyzer.cs | 2 +-
 .../Services/CodeAnalysisService_DesignerAttributes.cs        | 4 ++--
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/Features/Core/Portable/DesignerAttributes/IRemoteDesignerAttributeService.cs b/src/Features/Core/Portable/DesignerAttributes/IRemoteDesignerAttributeService.cs
index 3f09f0a062bc9..bd4076c010c78 100644
--- a/src/Features/Core/Portable/DesignerAttributes/IRemoteDesignerAttributeService.cs
+++ b/src/Features/Core/Portable/DesignerAttributes/IRemoteDesignerAttributeService.cs
@@ -8,6 +8,6 @@ namespace Microsoft.CodeAnalysis.DesignerAttributes
 {
     internal interface IRemoteDesignerAttributeService
     {
-        Task<IList<DesignerAttributeDocumentData>> ScanDesignerAttributesAsync(ProjectId projectId, CancellationToken cancellationToken);
+        Task<IReadOnlyList<DesignerAttributeDocumentData>> ScanDesignerAttributesAsync(ProjectId projectId, CancellationToken cancellationToken);
     }
 }
diff --git a/src/VisualStudio/Core/Def/Implementation/DesignerAttribute/DesignerAttributeIncrementalAnalyzer.cs b/src/VisualStudio/Core/Def/Implementation/DesignerAttribute/DesignerAttributeIncrementalAnalyzer.cs
index 6ceaa77b5d7b7..7dd8ee8705d5b 100644
--- a/src/VisualStudio/Core/Def/Implementation/DesignerAttribute/DesignerAttributeIncrementalAnalyzer.cs
+++ b/src/VisualStudio/Core/Def/Implementation/DesignerAttribute/DesignerAttributeIncrementalAnalyzer.cs
@@ -130,7 +130,7 @@ public async Task AnalyzeProjectAsync(Project project, bool semanticsChanged, In
                     return null;
                 }
 
-                var serializedResults = await session.InvokeAsync<IList<DesignerAttributeDocumentData>>(
+                var serializedResults = await session.InvokeAsync<IReadOnlyList<DesignerAttributeDocumentData>>(
                     nameof(IRemoteDesignerAttributeService.ScanDesignerAttributesAsync), new object[] { project.Id }, cancellationToken).ConfigureAwait(false);
 
                 var data = serializedResults.ToImmutableDictionary(kvp => kvp.FilePath);
diff --git a/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_DesignerAttributes.cs b/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_DesignerAttributes.cs
index 3aefc8e2ea1c3..8a49d29bd7f8a 100644
--- a/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_DesignerAttributes.cs
+++ b/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_DesignerAttributes.cs
@@ -19,7 +19,7 @@ internal partial class CodeAnalysisService : IRemoteDesignerAttributeService
         /// 
         /// This will be called by ServiceHub/JsonRpc framework
         /// </summary>
-        public async Task<IList<DesignerAttributeDocumentData>> ScanDesignerAttributesAsync(ProjectId projectId, CancellationToken cancellationToken)
+        public async Task<IReadOnlyList<DesignerAttributeDocumentData>> ScanDesignerAttributesAsync(ProjectId projectId, CancellationToken cancellationToken)
         {
             using (RoslynLogger.LogBlock(FunctionId.CodeAnalysisService_GetDesignerAttributesAsync, projectId.DebugName, cancellationToken))
             {
@@ -31,7 +31,7 @@ public async Task<IList<DesignerAttributeDocumentData>> ScanDesignerAttributesAs
 
                 if (data.Count == 0)
                 {
-                    return SpecializedCollections.EmptyList<DesignerAttributeDocumentData>();
+                    return SpecializedCollections.EmptyReadOnlyList<DesignerAttributeDocumentData>();
                 }
 
                 return data.Values.ToList();

From 27287419e15a55359cc56321d89c17a478673567 Mon Sep 17 00:00:00 2001
From: Fredric Silberberg <frsilb@microsoft.com>
Date: Wed, 9 Aug 2017 16:34:40 -0700
Subject: [PATCH 31/77] Removes IThrowStatement, replaces with nested
 IThrowExpression and IExpressionStatement.

---
 .../Operations/CSharpOperationFactory.cs      | 10 +--
 .../IOperationTests_IForEachLoopStatement.cs  | 19 +++---
 .../IOperationTests_IForLoopStatement.cs      | 11 ++--
 ...OperationTests_IWhileUntilLoopStatement.cs | 43 +++++++------
 .../Generated/Operations.xml.Generated.cs     | 61 -------------------
 .../Portable/Operations/IThrowStatement.cs    | 22 -------
 .../Portable/Operations/OperationCloner.cs    |  5 --
 .../Core/Portable/Operations/OperationKind.cs |  3 +-
 .../Portable/Operations/OperationVisitor.cs   | 10 ---
 .../Core/Portable/PublicAPI.Unshipped.txt     |  5 --
 .../Operations/VisualBasicOperationFactory.vb |  8 ++-
 .../IOperationTests_IForEachLoopStatement.vb  | 12 ++--
 ...OperationTests_IWhileUntilLoopStatement.vb | 36 ++++++-----
 .../Compilation/OperationTreeVerifier.cs      |  8 ---
 .../Compilation/TestOperationWalker.cs        |  5 --
 15 files changed, 74 insertions(+), 184 deletions(-)
 delete mode 100644 src/Compilers/Core/Portable/Operations/IThrowStatement.cs

diff --git a/src/Compilers/CSharp/Portable/Operations/CSharpOperationFactory.cs b/src/Compilers/CSharp/Portable/Operations/CSharpOperationFactory.cs
index bd1721ce525c0..6eed8a6cadb99 100644
--- a/src/Compilers/CSharp/Portable/Operations/CSharpOperationFactory.cs
+++ b/src/Compilers/CSharp/Portable/Operations/CSharpOperationFactory.cs
@@ -406,7 +406,7 @@ private IEventReferenceExpression CreateBoundEventAccessOperation(BoundEventAssi
 
         private IEventAssignmentExpression CreateBoundEventAssignmentOperatorOperation(BoundEventAssignmentOperator boundEventAssignmentOperator)
         {
-            Lazy<IEventReferenceExpression> eventReference = new Lazy<IEventReferenceExpression>(() => CreateBoundEventAccessOperation(boundEventAssignmentOperator));                
+            Lazy<IEventReferenceExpression> eventReference = new Lazy<IEventReferenceExpression>(() => CreateBoundEventAccessOperation(boundEventAssignmentOperator));
             Lazy<IOperation> handlerValue = new Lazy<IOperation>(() => Create(boundEventAssignmentOperator.Argument));
             SyntaxNode syntax = boundEventAssignmentOperator.Syntax;
             bool adds = boundEventAssignmentOperator.IsAddition;
@@ -1190,13 +1190,15 @@ private IUsingStatement CreateBoundUsingStatementOperation(BoundUsingStatement b
             return new LazyUsingStatement(body, declaration, value, _semanticModel, syntax, type, constantValue);
         }
 
-        private IThrowStatement CreateBoundThrowStatementOperation(BoundThrowStatement boundThrowStatement)
+        private IExpressionStatement CreateBoundThrowStatementOperation(BoundThrowStatement boundThrowStatement)
         {
             Lazy<IOperation> thrownObject = new Lazy<IOperation>(() => Create(boundThrowStatement.ExpressionOpt));
             SyntaxNode syntax = boundThrowStatement.Syntax;
-            ITypeSymbol type = null;
+            ITypeSymbol throwExpressionType = boundThrowStatement.ExpressionOpt?.Type;
+            ITypeSymbol statementType = null;
             Optional<object> constantValue = default(Optional<object>);
-            return new LazyThrowStatement(thrownObject, _semanticModel, syntax, type, constantValue);
+            IOperation throwExpression = new LazyThrowExpression(thrownObject, _semanticModel, syntax, throwExpressionType, constantValue);
+            return new ExpressionStatement(throwExpression, _semanticModel, syntax, statementType, constantValue);
         }
 
         private IReturnStatement CreateBoundReturnStatementOperation(BoundReturnStatement boundReturnStatement)
diff --git a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IForEachLoopStatement.cs b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IForEachLoopStatement.cs
index b161a1c21bf66..2693ab87f1da0 100644
--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IForEachLoopStatement.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IForEachLoopStatement.cs
@@ -724,7 +724,7 @@ static void Main(string[] args)
     }
 }
 ";
-string expectedOperationTree = @"
+            string expectedOperationTree = @"
 IForEachLoopStatement (Iteration variable: System.String x) (LoopKind.ForEach) (OperationKind.LoopStatement) (Syntax: 'foreach (st ... e)args) { }')
   Collection: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Collections.IEnumerable) (Syntax: '(IEnumerable)args')
       Conversion: CommonConversion (Exists: True, IsIdentity: True, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
@@ -770,14 +770,15 @@ static void Main()
             Left: ILocalReferenceExpression: num (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'num')
             Right: ILiteralExpression (Text: 3) (OperationKind.LiteralExpression, Type: System.Int32, Constant: 3) (Syntax: '3')
         IfTrue: IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: '{ ... }')
-            IThrowStatement (OperationKind.ThrowStatement) (Syntax: 'throw new S ... ""testing"");')
-              ThrownObject: IObjectCreationExpression (Constructor: System.Exception..ctor(System.String message)) (OperationKind.ObjectCreationExpression, Type: System.Exception) (Syntax: 'new System. ... (""testing"")')
-                  Arguments(1):
-                      IArgument (ArgumentKind.Explicit, Matching Parameter: message) (OperationKind.Argument) (Syntax: '""testing""')
-                        ILiteralExpression (OperationKind.LiteralExpression, Type: System.String, Constant: ""testing"") (Syntax: '""testing""')
-                        InConversion: null
-                        OutConversion: null
-                  Initializer: null
+            IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'throw new S ... ""testing"");')
+              Expression: IThrowExpression (OperationKind.ThrowExpression, Type: System.Exception) (Syntax: 'throw new S ... ""testing"");')
+                  IObjectCreationExpression (Constructor: System.Exception..ctor(System.String message)) (OperationKind.ObjectCreationExpression, Type: System.Exception) (Syntax: 'new System. ... (""testing"")')
+                    Arguments(1):
+                        IArgument (ArgumentKind.Explicit, Matching Parameter: message) (OperationKind.Argument) (Syntax: '""testing""')
+                          ILiteralExpression (OperationKind.LiteralExpression, Type: System.String, Constant: ""testing"") (Syntax: '""testing""')
+                          InConversion: null
+                          OutConversion: null
+                    Initializer: null
         IfFalse: null
       IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'System.Cons ... eLine(num);')
         Expression: IInvocationExpression (void System.Console.WriteLine(System.Int32 value)) (OperationKind.InvocationExpression, Type: System.Void) (Syntax: 'System.Cons ... teLine(num)')
diff --git a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IForLoopStatement.cs b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IForLoopStatement.cs
index 934286e1d5292..8ff97eba8e549 100644
--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IForLoopStatement.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IForLoopStatement.cs
@@ -1,4 +1,4 @@
-// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 using Microsoft.CodeAnalysis.Test.Utilities;
@@ -973,10 +973,11 @@ static void Main(string[] args)
                 Initializer: ILiteralExpression (Text: 0) (OperationKind.LiteralExpression, Type: System.Int32, Constant: 0) (Syntax: '0')
         AtLoopBottom(0)
         Body: IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: '{ ... }')
-            IThrowStatement (OperationKind.ThrowStatement) (Syntax: 'throw new S ... xception();')
-              ThrownObject: IObjectCreationExpression (Constructor: System.Exception..ctor()) (OperationKind.ObjectCreationExpression, Type: System.Exception) (Syntax: 'new System.Exception()')
-                  Arguments(0)
-                  Initializer: null
+            IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'throw new S ... xception();')
+              Expression: IThrowExpression (OperationKind.ThrowExpression, Type: System.Exception) (Syntax: 'throw new S ... xception();')
+                  IObjectCreationExpression (Constructor: System.Exception..ctor()) (OperationKind.ObjectCreationExpression, Type: System.Exception) (Syntax: 'new System.Exception()')
+                    Arguments(0)
+                    Initializer: null
 ";
             VerifyOperationTreeForTest<ForStatementSyntax>(source, expectedOperationTree);
         }
diff --git a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IWhileUntilLoopStatement.cs b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IWhileUntilLoopStatement.cs
index 01ab790f0be8c..1852e0c1d298c 100644
--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IWhileUntilLoopStatement.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IWhileUntilLoopStatement.cs
@@ -1,4 +1,4 @@
-// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
 using Microsoft.CodeAnalysis.CSharp.Syntax;
 using Microsoft.CodeAnalysis.Test.Utilities;
@@ -241,14 +241,15 @@ static void Main()
             Left: ILocalReferenceExpression: value (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'value')
             Right: ILiteralExpression (Text: 100) (OperationKind.LiteralExpression, Type: System.Int32, Constant: 100) (Syntax: '100')
         IfTrue: IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: '{ ... }')
-            IThrowStatement (OperationKind.ThrowStatement) (Syntax: 'throw new E ... ever hit"");')
-              ThrownObject: IObjectCreationExpression (Constructor: System.Exception..ctor(System.String message)) (OperationKind.ObjectCreationExpression, Type: System.Exception) (Syntax: 'new Excepti ... Never hit"")')
-                  Arguments(1):
-                      IArgument (ArgumentKind.Explicit, Matching Parameter: message) (OperationKind.Argument) (Syntax: '""Never hit""')
-                        ILiteralExpression (OperationKind.LiteralExpression, Type: System.String, Constant: ""Never hit"") (Syntax: '""Never hit""')
-                        InConversion: null
-                        OutConversion: null
-                  Initializer: null
+            IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'throw new E ... ever hit"");')
+              Expression: IThrowExpression (OperationKind.ThrowExpression, Type: System.Exception) (Syntax: 'throw new E ... ever hit"");')
+                  IObjectCreationExpression (Constructor: System.Exception..ctor(System.String message)) (OperationKind.ObjectCreationExpression, Type: System.Exception) (Syntax: 'new Excepti ... Never hit"")')
+                    Arguments(1):
+                        IArgument (ArgumentKind.Explicit, Matching Parameter: message) (OperationKind.Argument) (Syntax: '""Never hit""')
+                          ILiteralExpression (OperationKind.LiteralExpression, Type: System.String, Constant: ""Never hit"") (Syntax: '""Never hit""')
+                          InConversion: null
+                          OutConversion: null
+                    Initializer: null
         IfFalse: null
       IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'Console.Wri ... tatement"");')
         Expression: IInvocationExpression (void System.Console.WriteLine(System.String value)) (OperationKind.InvocationExpression, Type: System.Void) (Syntax: 'Console.Wri ... statement"")')
@@ -283,7 +284,7 @@ static void Main()
     }
 }
 ";
-string expectedOperationTree = @"
+            string expectedOperationTree = @"
 IWhileUntilLoopStatement (IsTopTest: True, IsWhile: True) (LoopKind.WhileUntil) (OperationKind.LoopStatement) (Syntax: 'while ((i = ... }')
   Condition: IBinaryOperatorExpression (BinaryOperationKind.IntegerGreaterThanOrEqual) (OperationKind.BinaryOperatorExpression, Type: System.Boolean) (Syntax: '(i = value) >= 0')
       Left: ISimpleAssignmentExpression (OperationKind.SimpleAssignmentExpression, Type: System.Int32) (Syntax: 'i = value')
@@ -314,6 +315,7 @@ static void Main()
       IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'value--;')
         Expression: IIncrementExpression (UnaryOperandKind.IntegerPostfixDecrement) (OperationKind.IncrementExpression, Type: System.Int32) (Syntax: 'value--')
             Left: ILocalReferenceExpression: value (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'value')
+
 ";
             VerifyOperationTreeForTest<WhileStatementSyntax>(source, expectedOperationTree);
         }
@@ -334,7 +336,7 @@ static void Main()
     }
 }
 ";
-string expectedOperationTree = @"
+            string expectedOperationTree = @"
 IWhileUntilLoopStatement (IsTopTest: True, IsWhile: True) (LoopKind.WhileUntil) (OperationKind.LoopStatement, IsInvalid) (Syntax: 'while (numb ... }')
   Condition: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Boolean, IsInvalid) (Syntax: 'number')
       Conversion: CommonConversion (Exists: True, IsIdentity: True, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
@@ -370,7 +372,7 @@ public static int GetFirstEvenNumber(int number)
 }
 ";
 
-string expectedOperationTree = @"
+            string expectedOperationTree = @"
 IWhileUntilLoopStatement (IsTopTest: True, IsWhile: True) (LoopKind.WhileUntil) (OperationKind.LoopStatement) (Syntax: 'while (true ... }')
   Condition: ILiteralExpression (OperationKind.LiteralExpression, Type: System.Boolean, Constant: True) (Syntax: 'true')
   Body: IBlockStatement (2 statements) (OperationKind.BlockStatement) (Syntax: '{ ... }')
@@ -463,7 +465,7 @@ static void Main()
     }
 }
 ";
-string expectedOperationTree = @"
+            string expectedOperationTree = @"
 IWhileUntilLoopStatement (IsTopTest: True, IsWhile: True) (LoopKind.WhileUntil) (OperationKind.LoopStatement, IsInvalid) (Syntax: 'while () ... }')
   Condition: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Boolean, IsInvalid) (Syntax: '')
       Conversion: CommonConversion (Exists: True, IsIdentity: True, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
@@ -507,7 +509,7 @@ static void Main()
     }
 }
 ";
-string expectedOperationTree = @"
+            string expectedOperationTree = @"
 IWhileUntilLoopStatement (IsTopTest: True, IsWhile: True) (LoopKind.WhileUntil) (OperationKind.LoopStatement) (Syntax: 'while(i <=  ... }')
   Condition: IBinaryOperatorExpression (BinaryOperationKind.IntegerLessThanOrEqual) (OperationKind.BinaryOperatorExpression, Type: System.Boolean) (Syntax: 'i <= 10')
       Left: ILocalReferenceExpression: i (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'i')
@@ -887,7 +889,7 @@ public void TryMethod()
     }
 }
 ";
-string expectedOperationTree = @"
+            string expectedOperationTree = @"
 IWhileUntilLoopStatement (IsTopTest: True, IsWhile: True) (LoopKind.WhileUntil) (OperationKind.LoopStatement) (Syntax: 'while (x--  ... }')
   Condition: IBinaryOperatorExpression (BinaryOperationKind.IntegerGreaterThan) (OperationKind.BinaryOperatorExpression, Type: System.Boolean) (Syntax: 'x-- > 0')
       Left: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Int32) (Syntax: 'x--')
@@ -910,10 +912,11 @@ public void TryMethod()
                           Right: ILiteralExpression (Text: 2) (OperationKind.LiteralExpression, Type: System.Int32, Constant: 2) (Syntax: '2')
         Catch clauses(0)
         Finally: IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: '{ ... }')
-            IThrowStatement (OperationKind.ThrowStatement) (Syntax: 'throw new S ... xception();')
-              ThrownObject: IObjectCreationExpression (Constructor: System.Exception..ctor()) (OperationKind.ObjectCreationExpression, Type: System.Exception) (Syntax: 'new System.Exception()')
-                  Arguments(0)
-                  Initializer: null
+            IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'throw new S ... xception();')
+              Expression: IThrowExpression (OperationKind.ThrowExpression, Type: System.Exception) (Syntax: 'throw new S ... xception();')
+                  IObjectCreationExpression (Constructor: System.Exception..ctor()) (OperationKind.ObjectCreationExpression, Type: System.Exception) (Syntax: 'new System.Exception()')
+                    Arguments(0)
+                    Initializer: null
 ";
             VerifyOperationTreeForTest<WhileStatementSyntax>(source, expectedOperationTree);
         }
@@ -949,7 +952,7 @@ static bool TakeOutParam<T>(T y, out T x)
     }
 }
 ";
-string expectedOperationTree = @"
+            string expectedOperationTree = @"
 IWhileUntilLoopStatement (IsTopTest: True, IsWhile: True) (LoopKind.WhileUntil) (OperationKind.LoopStatement) (Syntax: 'while (Dumm ... }')
   Condition: IInvocationExpression (System.Boolean X.Dummy(System.Boolean x, System.Object y, System.Object z)) (OperationKind.InvocationExpression, Type: System.Boolean) (Syntax: 'Dummy(f, Ta ... ar x1), x1)')
       Instance Receiver: null
diff --git a/src/Compilers/Core/Portable/Generated/Operations.xml.Generated.cs b/src/Compilers/Core/Portable/Generated/Operations.xml.Generated.cs
index 2db8a93319f5b..72f488587fa16 100644
--- a/src/Compilers/Core/Portable/Generated/Operations.xml.Generated.cs
+++ b/src/Compilers/Core/Portable/Generated/Operations.xml.Generated.cs
@@ -4271,67 +4271,6 @@ internal sealed partial class LazySyntheticLocalReferenceExpression : BaseSynthe
         }
     }
 
-    /// <summary>
-    /// Represents a C# throw or a VB Throw statement.
-    /// </summary>
-    internal abstract partial class BaseThrowStatement : Operation, IThrowStatement
-    {
-        protected BaseThrowStatement(SemanticModel semanticModel, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) :
-                    base(OperationKind.ThrowStatement, semanticModel, syntax, type, constantValue)
-        {
-        }
-
-        protected abstract IOperation ThrownObjectImpl { get; }
-        public override IEnumerable<IOperation> Children
-        {
-            get
-            {
-                yield return ThrownObject;
-            }
-        }
-        /// <summary>
-        /// Value to be thrown.
-        /// </summary>
-        public IOperation ThrownObject => Operation.SetParentOperation(ThrownObjectImpl, this);
-        public override void Accept(OperationVisitor visitor)
-        {
-            visitor.VisitThrowStatement(this);
-        }
-        public override TResult Accept<TArgument, TResult>(OperationVisitor<TArgument, TResult> visitor, TArgument argument)
-        {
-            return visitor.VisitThrowStatement(this, argument);
-        }
-    }
-
-    /// <summary>
-    /// Represents a C# throw or a VB Throw statement.
-    /// </summary>
-    internal sealed partial class ThrowStatement : BaseThrowStatement, IThrowStatement
-    {
-        public ThrowStatement(IOperation thrownObject, SemanticModel semanticModel, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) :
-            base(semanticModel, syntax, type, constantValue)
-        {
-            ThrownObjectImpl = thrownObject;
-        }
-
-        protected override IOperation ThrownObjectImpl { get; }
-    }
-
-    /// <summary>
-    /// Represents a C# throw or a VB Throw statement.
-    /// </summary>
-    internal sealed partial class LazyThrowStatement : BaseThrowStatement, IThrowStatement
-    {
-        private readonly Lazy<IOperation> _lazyThrownObject;
-
-        public LazyThrowStatement(Lazy<IOperation> thrownObject, SemanticModel semanticModel, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) : base(semanticModel, syntax, type, constantValue)
-        {
-            _lazyThrownObject = thrownObject ?? throw new System.ArgumentNullException(nameof(thrownObject));
-        }
-
-        protected override IOperation ThrownObjectImpl => _lazyThrownObject.Value;
-    }
-
     /// <summary>
     /// Represents a C# try or a VB Try statement.
     /// </summary>
diff --git a/src/Compilers/Core/Portable/Operations/IThrowStatement.cs b/src/Compilers/Core/Portable/Operations/IThrowStatement.cs
deleted file mode 100644
index e77669ae6ea93..0000000000000
--- a/src/Compilers/Core/Portable/Operations/IThrowStatement.cs
+++ /dev/null
@@ -1,22 +0,0 @@
-// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
-
-using System.Collections.Immutable;
-
-namespace Microsoft.CodeAnalysis.Semantics
-{
-    /// <summary>
-    /// Represents a C# throw or a VB Throw statement.
-    /// </summary>
-    /// <remarks>
-    /// This interface is reserved for implementation by its associated APIs. We reserve the right to
-    /// change it in the future.
-    /// </remarks>
-    public interface IThrowStatement : IOperation
-    {
-        /// <summary>
-        /// Value to be thrown.
-        /// </summary>
-        IOperation ThrownObject { get; }
-    }
-}
-
diff --git a/src/Compilers/Core/Portable/Operations/OperationCloner.cs b/src/Compilers/Core/Portable/Operations/OperationCloner.cs
index 038de6c65fd1c..b372eba8aa0e2 100644
--- a/src/Compilers/Core/Portable/Operations/OperationCloner.cs
+++ b/src/Compilers/Core/Portable/Operations/OperationCloner.cs
@@ -119,11 +119,6 @@ public override IOperation VisitEmptyStatement(IEmptyStatement operation, object
             return new EmptyStatement(((Operation)operation).SemanticModel, operation.Syntax, operation.Type, operation.ConstantValue);
         }
 
-        public override IOperation VisitThrowStatement(IThrowStatement operation, object argument)
-        {
-            return new ThrowStatement(Visit(operation.ThrownObject), ((Operation)operation).SemanticModel, operation.Syntax, operation.Type, operation.ConstantValue);
-        }
-
         public override IOperation VisitReturnStatement(IReturnStatement operation, object argument)
         {
             return new ReturnStatement(operation.Kind, Visit(operation.ReturnedValue), ((Operation)operation).SemanticModel, operation.Syntax, operation.Type, operation.ConstantValue);
diff --git a/src/Compilers/Core/Portable/Operations/OperationKind.cs b/src/Compilers/Core/Portable/Operations/OperationKind.cs
index f0a17227330cd..fcc964f5283b8 100644
--- a/src/Compilers/Core/Portable/Operations/OperationKind.cs
+++ b/src/Compilers/Core/Portable/Operations/OperationKind.cs
@@ -31,8 +31,7 @@ public enum OperationKind
         BranchStatement = 0x8,
         /// <summary>Indicates an <see cref="IEmptyStatement"/>.</summary>
         EmptyStatement = 0x9,
-        /// <summary>Indicates an <see cref="IThrowStatement"/>.</summary>
-        ThrowStatement = 0xa,
+        // 0xa open for usage, was IThrowStatement.
         /// <summary>Indicates an <see cref="IReturnStatement"/>.</summary>
         ReturnStatement = 0xb,
         /// <summary>Indicates an <see cref="IReturnStatement"/>.</summary>
diff --git a/src/Compilers/Core/Portable/Operations/OperationVisitor.cs b/src/Compilers/Core/Portable/Operations/OperationVisitor.cs
index 56c1f3b4db093..2825afa9bc999 100644
--- a/src/Compilers/Core/Portable/Operations/OperationVisitor.cs
+++ b/src/Compilers/Core/Portable/Operations/OperationVisitor.cs
@@ -110,11 +110,6 @@ public virtual void VisitEmptyStatement(IEmptyStatement operation)
             DefaultVisit(operation);
         }
 
-        public virtual void VisitThrowStatement(IThrowStatement operation)
-        {
-            DefaultVisit(operation);
-        }
-
         public virtual void VisitReturnStatement(IReturnStatement operation)
         {
             DefaultVisit(operation);
@@ -580,11 +575,6 @@ public virtual TResult VisitEmptyStatement(IEmptyStatement operation, TArgument
             return DefaultVisit(operation, argument);
         }
 
-        public virtual TResult VisitThrowStatement(IThrowStatement operation, TArgument argument)
-        {
-            return DefaultVisit(operation, argument);
-        }
-
         public virtual TResult VisitReturnStatement(IReturnStatement operation, TArgument argument)
         {
             return DefaultVisit(operation, argument);
diff --git a/src/Compilers/Core/Portable/PublicAPI.Unshipped.txt b/src/Compilers/Core/Portable/PublicAPI.Unshipped.txt
index a9d2055d6d0f1..4c219bd73bf0a 100644
--- a/src/Compilers/Core/Portable/PublicAPI.Unshipped.txt
+++ b/src/Compilers/Core/Portable/PublicAPI.Unshipped.txt
@@ -124,7 +124,6 @@ Microsoft.CodeAnalysis.OperationKind.SwitchCase = 1033 -> Microsoft.CodeAnalysis
 Microsoft.CodeAnalysis.OperationKind.SwitchStatement = 4 -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.OperationKind.SyntheticLocalReferenceExpression = 263 -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.OperationKind.ThrowExpression = 519 -> Microsoft.CodeAnalysis.OperationKind
-Microsoft.CodeAnalysis.OperationKind.ThrowStatement = 10 -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.OperationKind.TryStatement = 14 -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.OperationKind.TupleExpression = 292 -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.OperationKind.TypeOfExpression = 513 -> Microsoft.CodeAnalysis.OperationKind
@@ -565,8 +564,6 @@ Microsoft.CodeAnalysis.Semantics.ISyntheticLocalReferenceExpression
 Microsoft.CodeAnalysis.Semantics.ISyntheticLocalReferenceExpression.SyntheticLocalKind.get -> Microsoft.CodeAnalysis.Semantics.SyntheticLocalKind
 Microsoft.CodeAnalysis.Semantics.IThrowExpression
 Microsoft.CodeAnalysis.Semantics.IThrowExpression.Expression.get -> Microsoft.CodeAnalysis.IOperation
-Microsoft.CodeAnalysis.Semantics.IThrowStatement
-Microsoft.CodeAnalysis.Semantics.IThrowStatement.ThrownObject.get -> Microsoft.CodeAnalysis.IOperation
 Microsoft.CodeAnalysis.Semantics.ITryStatement
 Microsoft.CodeAnalysis.Semantics.ITryStatement.Body.get -> Microsoft.CodeAnalysis.Semantics.IBlockStatement
 Microsoft.CodeAnalysis.Semantics.ITryStatement.Catches.get -> System.Collections.Immutable.ImmutableArray<Microsoft.CodeAnalysis.Semantics.ICatchClause>
@@ -850,7 +847,6 @@ virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitSwitchCase(Micros
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitSwitchStatement(Microsoft.CodeAnalysis.Semantics.ISwitchStatement operation) -> void
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitSyntheticLocalReferenceExpression(Microsoft.CodeAnalysis.Semantics.ISyntheticLocalReferenceExpression operation) -> void
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitThrowExpression(Microsoft.CodeAnalysis.Semantics.IThrowExpression operation) -> void
-virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitThrowStatement(Microsoft.CodeAnalysis.Semantics.IThrowStatement operation) -> void
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitTryStatement(Microsoft.CodeAnalysis.Semantics.ITryStatement operation) -> void
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitTupleExpression(Microsoft.CodeAnalysis.Semantics.ITupleExpression operation) -> void
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitTypeOfExpression(Microsoft.CodeAnalysis.Semantics.ITypeOfExpression operation) -> void
@@ -940,7 +936,6 @@ virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.Vi
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitSwitchStatement(Microsoft.CodeAnalysis.Semantics.ISwitchStatement operation, TArgument argument) -> TResult
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitSyntheticLocalReferenceExpression(Microsoft.CodeAnalysis.Semantics.ISyntheticLocalReferenceExpression operation, TArgument argument) -> TResult
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitThrowExpression(Microsoft.CodeAnalysis.Semantics.IThrowExpression operation, TArgument argument) -> TResult
-virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitThrowStatement(Microsoft.CodeAnalysis.Semantics.IThrowStatement operation, TArgument argument) -> TResult
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitTryStatement(Microsoft.CodeAnalysis.Semantics.ITryStatement operation, TArgument argument) -> TResult
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitTupleExpression(Microsoft.CodeAnalysis.Semantics.ITupleExpression operation, TArgument argument) -> TResult
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitTypeOfExpression(Microsoft.CodeAnalysis.Semantics.ITypeOfExpression operation, TArgument argument) -> TResult
diff --git a/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb b/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
index 8eed84d14b050..6f27c4f6bb694 100644
--- a/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
+++ b/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
@@ -963,12 +963,14 @@ Namespace Microsoft.CodeAnalysis.Semantics
             Return New LazyReturnStatement(OperationKind.ReturnStatement, returnedValue, _semanticModel, syntax, type, constantValue)
         End Function
 
-        Private Function CreateBoundThrowStatementOperation(boundThrowStatement As BoundThrowStatement) As IThrowStatement
+        Private Function CreateBoundThrowStatementOperation(boundThrowStatement As BoundThrowStatement) As IExpressionStatement
             Dim thrownObject As Lazy(Of IOperation) = New Lazy(Of IOperation)(Function() Create(boundThrowStatement.ExpressionOpt))
             Dim syntax As SyntaxNode = boundThrowStatement.Syntax
-            Dim type As ITypeSymbol = Nothing
+            Dim expressionType As ITypeSymbol = boundThrowStatement.ExpressionOpt?.Type
+            Dim statementType As ITypeSymbol = Nothing
             Dim constantValue As [Optional](Of Object) = New [Optional](Of Object)()
-            Return New LazyThrowStatement(thrownObject, _semanticModel, syntax, type, constantValue)
+            Dim throwExpression As IOperation = New LazyThrowExpression(thrownObject, _semanticModel, syntax, expressionType, constantValue)
+            Return New ExpressionStatement(throwExpression, _semanticModel, syntax, statementType, constantValue)
         End Function
 
         Private Function CreateBoundWhileStatementOperation(boundWhileStatement As BoundWhileStatement) As IWhileUntilLoopStatement
diff --git a/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_IForEachLoopStatement.vb b/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_IForEachLoopStatement.vb
index 338e2a06ff80e..ca291a6a62513 100644
--- a/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_IForEachLoopStatement.vb
+++ b/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_IForEachLoopStatement.vb
@@ -751,10 +751,11 @@ IForEachLoopStatement (Iteration variable: null) (LoopKind.ForEach) (OperationKi
                 Left: ILocalReferenceExpression: s (OperationKind.LocalReferenceExpression, Type: System.String) (Syntax: 's')
                 Right: ILiteralExpression (OperationKind.LiteralExpression, Type: System.String, Constant: "one") (Syntax: '"one"')
         IfTrue: IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: 'If (s = "on ... End If')
-            IThrowStatement (OperationKind.ThrowStatement) (Syntax: 'Throw New Exception')
-              ThrownObject: IObjectCreationExpression (Constructor: Sub System.Exception..ctor()) (OperationKind.ObjectCreationExpression, Type: System.Exception) (Syntax: 'New Exception')
-                  Arguments(0)
-                  Initializer: null
+            IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'Throw New Exception')
+              Expression: IThrowExpression (OperationKind.ThrowExpression, Type: System.Exception) (Syntax: 'Throw New Exception')
+                  IObjectCreationExpression (Constructor: Sub System.Exception..ctor()) (OperationKind.ObjectCreationExpression, Type: System.Exception) (Syntax: 'New Exception')
+                    Arguments(0)
+                    Initializer: null
         IfFalse: null
       IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'Console.WriteLine(s)')
         Expression: IInvocationExpression (Sub System.Console.WriteLine(value As System.String)) (OperationKind.InvocationExpression, Type: System.Void) (Syntax: 'Console.WriteLine(s)')
@@ -763,8 +764,7 @@ IForEachLoopStatement (Iteration variable: null) (LoopKind.ForEach) (OperationKi
                 IArgument (ArgumentKind.Explicit, Matching Parameter: value) (OperationKind.Argument) (Syntax: 's')
                   ILocalReferenceExpression: s (OperationKind.LocalReferenceExpression, Type: System.String) (Syntax: 's')
                   InConversion: null
-                  OutConversion: null
-]]>.Value
+                  OutConversion: null]]>.Value
 
             VerifyOperationTreeForTest(Of ForEachBlockSyntax)(source, expectedOperationTree)
         End Sub
diff --git a/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_IWhileUntilLoopStatement.vb b/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_IWhileUntilLoopStatement.vb
index 6ec963d505b87..7f53240dbcb68 100644
--- a/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_IWhileUntilLoopStatement.vb
+++ b/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_IWhileUntilLoopStatement.vb
@@ -238,14 +238,15 @@ IWhileUntilLoopStatement (IsTopTest: True, IsWhile: True) (LoopKind.WhileUntil)
             Left: ILocalReferenceExpression: value (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'value')
             Right: ILiteralExpression (Text: 100) (OperationKind.LiteralExpression, Type: System.Int32, Constant: 100) (Syntax: '100')
         IfTrue: IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: 'If value >  ... End If')
-            IThrowStatement (OperationKind.ThrowStatement) (Syntax: 'Throw New S ... occurred.")')
-              ThrownObject: IObjectCreationExpression (Constructor: Sub System.Exception..ctor(message As System.String)) (OperationKind.ObjectCreationExpression, Type: System.Exception) (Syntax: 'New System. ... occurred.")')
-                  Arguments(1):
-                      IArgument (ArgumentKind.Explicit, Matching Parameter: message) (OperationKind.Argument) (Syntax: '"An excepti ...  occurred."')
-                        ILiteralExpression (OperationKind.LiteralExpression, Type: System.String, Constant: "An exception has occurred.") (Syntax: '"An excepti ...  occurred."')
-                        InConversion: null
-                        OutConversion: null
-                  Initializer: null
+            IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'Throw New S ... occurred.")')
+              Expression: IThrowExpression (OperationKind.ThrowExpression, Type: System.Exception) (Syntax: 'Throw New S ... occurred.")')
+                  IObjectCreationExpression (Constructor: Sub System.Exception..ctor(message As System.String)) (OperationKind.ObjectCreationExpression, Type: System.Exception) (Syntax: 'New System. ... occurred.")')
+                    Arguments(1):
+                        IArgument (ArgumentKind.Explicit, Matching Parameter: message) (OperationKind.Argument) (Syntax: '"An excepti ...  occurred."')
+                          ILiteralExpression (OperationKind.LiteralExpression, Type: System.String, Constant: "An exception has occurred.") (Syntax: '"An excepti ...  occurred."')
+                          InConversion: null
+                          OutConversion: null
+                    Initializer: null
         IfFalse: null
       IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'System.Cons ... statement")')
         Expression: IInvocationExpression (Sub System.Console.WriteLine(value As System.String)) (OperationKind.InvocationExpression, Type: System.Void) (Syntax: 'System.Cons ... statement")')
@@ -254,8 +255,7 @@ IWhileUntilLoopStatement (IsTopTest: True, IsWhile: True) (LoopKind.WhileUntil)
                 IArgument (ArgumentKind.Explicit, Matching Parameter: value) (OperationKind.Argument) (Syntax: '"While-loop statement"')
                   ILiteralExpression (OperationKind.LiteralExpression, Type: System.String, Constant: "While-loop statement") (Syntax: '"While-loop statement"')
                   InConversion: null
-                  OutConversion: null
-]]>.Value
+                  OutConversion: null]]>.Value
 
             VerifyOperationTreeForTest(Of WhileBlockSyntax)(source, expectedOperationTree)
         End Sub
@@ -320,8 +320,7 @@ IWhileUntilLoopStatement (IsTopTest: True, IsWhile: True) (LoopKind.WhileUntil)
       IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'value -= 1')
         Expression: ICompoundAssignmentExpression (BinaryOperationKind.IntegerSubtract) (OperationKind.CompoundAssignmentExpression, Type: System.Int32) (Syntax: 'value -= 1')
             Left: ILocalReferenceExpression: value (OperationKind.LocalReferenceExpression, Type: System.Int32) (Syntax: 'value')
-            Right: ILiteralExpression (Text: 1) (OperationKind.LiteralExpression, Type: System.Int32, Constant: 1) (Syntax: '1')
-]]>.Value
+            Right: ILiteralExpression (Text: 1) (OperationKind.LiteralExpression, Type: System.Int32, Constant: 1) (Syntax: '1')]]>.Value
 
             VerifyOperationTreeForTest(Of WhileBlockSyntax)(source, expectedOperationTree)
         End Sub
@@ -901,11 +900,11 @@ IWhileUntilLoopStatement (IsTopTest: True, IsWhile: True) (LoopKind.WhileUntil)
                               Operand: ILiteralExpression (Text: 2) (OperationKind.LiteralExpression, Type: System.Int32, Constant: 2) (Syntax: '2')
         Catch clauses(0)
         Finally: IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: 'Finally ... Exception()')
-            IThrowStatement (OperationKind.ThrowStatement) (Syntax: 'Throw New S ... Exception()')
-              ThrownObject: IObjectCreationExpression (Constructor: Sub System.Exception..ctor()) (OperationKind.ObjectCreationExpression, Type: System.Exception) (Syntax: 'New System.Exception()')
-                  Arguments(0)
-                  Initializer: null
-]]>.Value
+            IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'Throw New S ... Exception()')
+              Expression: IThrowExpression (OperationKind.ThrowExpression, Type: System.Exception) (Syntax: 'Throw New S ... Exception()')
+                  IObjectCreationExpression (Constructor: Sub System.Exception..ctor()) (OperationKind.ObjectCreationExpression, Type: System.Exception) (Syntax: 'New System.Exception()')
+                    Arguments(0)
+                    Initializer: null]]>.Value
 
             VerifyOperationTreeForTest(Of WhileBlockSyntax)(source, expectedOperationTree)
         End Sub
@@ -942,8 +941,7 @@ IWhileUntilLoopStatement (IsTopTest: True, IsWhile: True) (LoopKind.WhileUntil)
                 IArgument (ArgumentKind.Explicit, Matching Parameter: value) (OperationKind.Argument) (Syntax: '1')
                   ILiteralExpression (Text: 1) (OperationKind.LiteralExpression, Type: System.Int32, Constant: 1) (Syntax: '1')
                   InConversion: null
-                  OutConversion: null
-]]>.Value
+                  OutConversion: null]]>.Value
 
             VerifyOperationTreeForTest(Of DoLoopBlockSyntax)(source, expectedOperationTree)
         End Sub
diff --git a/src/Test/Utilities/Portable/Compilation/OperationTreeVerifier.cs b/src/Test/Utilities/Portable/Compilation/OperationTreeVerifier.cs
index 6b7250fa0b2d6..bc8b44b4ad97a 100644
--- a/src/Test/Utilities/Portable/Compilation/OperationTreeVerifier.cs
+++ b/src/Test/Utilities/Portable/Compilation/OperationTreeVerifier.cs
@@ -494,14 +494,6 @@ public override void VisitEmptyStatement(IEmptyStatement operation)
             LogCommonPropertiesAndNewLine(operation);
         }
 
-        public override void VisitThrowStatement(IThrowStatement operation)
-        {
-            LogString(nameof(IThrowStatement));
-            LogCommonPropertiesAndNewLine(operation);
-
-            Visit(operation.ThrownObject, "ThrownObject");
-        }
-
         public override void VisitReturnStatement(IReturnStatement operation)
         {
             LogString(nameof(IReturnStatement));
diff --git a/src/Test/Utilities/Portable/Compilation/TestOperationWalker.cs b/src/Test/Utilities/Portable/Compilation/TestOperationWalker.cs
index ae9cdd4978e9c..e4d47fa84884d 100644
--- a/src/Test/Utilities/Portable/Compilation/TestOperationWalker.cs
+++ b/src/Test/Utilities/Portable/Compilation/TestOperationWalker.cs
@@ -154,11 +154,6 @@ public override void VisitEmptyStatement(IEmptyStatement operation)
             base.VisitEmptyStatement(operation);
         }
 
-        public override void VisitThrowStatement(IThrowStatement operation)
-        {
-            base.VisitThrowStatement(operation);
-        }
-
         public override void VisitReturnStatement(IReturnStatement operation)
         {
             base.VisitReturnStatement(operation);

From 7734a6f094ceb05b39388b2bae4f2d8924b8f006 Mon Sep 17 00:00:00 2001
From: Fredric Silberberg <frsilb@microsoft.com>
Date: Wed, 9 Aug 2017 16:57:33 -0700
Subject: [PATCH 32/77] Remove IThrowStatement from IDE code.

---
 .../AbstractUseThrowExpressionDiagnosticAnalyzer.cs | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/src/Features/Core/Portable/UseThrowExpression/AbstractUseThrowExpressionDiagnosticAnalyzer.cs b/src/Features/Core/Portable/UseThrowExpression/AbstractUseThrowExpressionDiagnosticAnalyzer.cs
index 701173ec6f89a..9d4c33a42670f 100644
--- a/src/Features/Core/Portable/UseThrowExpression/AbstractUseThrowExpressionDiagnosticAnalyzer.cs
+++ b/src/Features/Core/Portable/UseThrowExpression/AbstractUseThrowExpressionDiagnosticAnalyzer.cs
@@ -62,7 +62,7 @@ protected override void InitializeWorker(AnalysisContext context)
                 s_registerOperationActionInfo.Invoke(startContext, new object[]
                 {
                     new Action<OperationAnalysisContext>(operationContext => AnalyzeOperation(operationContext, expressionTypeOpt)),
-                    ImmutableArray.Create(OperationKind.ThrowStatement)
+                    ImmutableArray.Create(OperationKind.ExpressionStatement)
                 });
             });
         }
@@ -77,7 +77,12 @@ private void AnalyzeOperation(OperationAnalysisContext context, INamedTypeSymbol
 
             var cancellationToken = context.CancellationToken;
 
-            var throwOperation = (IThrowStatement)context.Operation;
+            var throwOperation = (IExpressionStatement)context.Operation;
+            if (throwOperation.Expression.Kind != OperationKind.ThrowExpression)
+            {
+                return;
+            }
+
             var throwStatement = throwOperation.Syntax;
             var options = context.Options;
             var optionSet = options.GetDocumentOptionSetAsync(syntaxTree, cancellationToken).GetAwaiter().GetResult();
@@ -159,7 +164,7 @@ private void AnalyzeOperation(OperationAnalysisContext context, INamedTypeSymbol
 
             var allLocations = ImmutableArray.Create(
                 ifOperation.Syntax.GetLocation(),
-                throwOperation.ThrownObject.Syntax.GetLocation(),
+                throwOperation.Expression.Syntax.GetLocation(),
                 assignmentExpression.Value.Syntax.GetLocation());
 
             var descriptor = GetDescriptorWithSeverity(option.Notification.Value);
@@ -293,7 +298,7 @@ private bool IsNull(IOperation operation)
         }
 
         private IIfStatement GetContainingIfOperation(
-            SemanticModel semanticModel, IThrowStatement throwOperation,
+            SemanticModel semanticModel, IExpressionStatement throwOperation,
             CancellationToken cancellationToken)
         {
             var throwStatement = throwOperation.Syntax;

From ac280f3ea5cb080d429b1c0303485eeed442af0d Mon Sep 17 00:00:00 2001
From: Fredric Silberberg <frsilb@microsoft.com>
Date: Thu, 10 Aug 2017 10:51:59 -0700
Subject: [PATCH 33/77] Fix diagnostic location.

---
 .../AbstractUseThrowExpressionDiagnosticAnalyzer.cs             | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Features/Core/Portable/UseThrowExpression/AbstractUseThrowExpressionDiagnosticAnalyzer.cs b/src/Features/Core/Portable/UseThrowExpression/AbstractUseThrowExpressionDiagnosticAnalyzer.cs
index 9d4c33a42670f..9ac2c029e99a0 100644
--- a/src/Features/Core/Portable/UseThrowExpression/AbstractUseThrowExpressionDiagnosticAnalyzer.cs
+++ b/src/Features/Core/Portable/UseThrowExpression/AbstractUseThrowExpressionDiagnosticAnalyzer.cs
@@ -164,7 +164,7 @@ private void AnalyzeOperation(OperationAnalysisContext context, INamedTypeSymbol
 
             var allLocations = ImmutableArray.Create(
                 ifOperation.Syntax.GetLocation(),
-                throwOperation.Expression.Syntax.GetLocation(),
+                ((IThrowExpression)throwOperation.Expression).Expression.Syntax.GetLocation(),
                 assignmentExpression.Value.Syntax.GetLocation());
 
             var descriptor = GetDescriptorWithSeverity(option.Notification.Value);

From d18797b8dee1559d5a85bacb0d834727e6f630c7 Mon Sep 17 00:00:00 2001
From: Fredric Silberberg <frsilb@microsoft.com>
Date: Thu, 10 Aug 2017 12:47:06 -0700
Subject: [PATCH 34/77] Made UseThrowExpression analyzer look for
 ThrowExpressions and use Parent, instead of traversing the other direction.

---
 ...actUseThrowExpressionDiagnosticAnalyzer.cs | 25 ++++++++++---------
 1 file changed, 13 insertions(+), 12 deletions(-)

diff --git a/src/Features/Core/Portable/UseThrowExpression/AbstractUseThrowExpressionDiagnosticAnalyzer.cs b/src/Features/Core/Portable/UseThrowExpression/AbstractUseThrowExpressionDiagnosticAnalyzer.cs
index 9ac2c029e99a0..2a4e212954cb9 100644
--- a/src/Features/Core/Portable/UseThrowExpression/AbstractUseThrowExpressionDiagnosticAnalyzer.cs
+++ b/src/Features/Core/Portable/UseThrowExpression/AbstractUseThrowExpressionDiagnosticAnalyzer.cs
@@ -18,17 +18,17 @@ namespace Microsoft.CodeAnalysis.UseThrowExpression
     /// if (a == null) {
     ///   throw SomeException();
     /// }
-    /// 
+    ///
     /// x = a;
     /// </code>
-    /// 
+    ///
     /// and offers to change it to
-    /// 
+    ///
     /// <code>
     /// x = a ?? throw SomeException();
     /// </code>
-    /// 
-    /// Note: this analyzer can be updated to run on VB once VB supports 'throw' 
+    ///
+    /// Note: this analyzer can be updated to run on VB once VB supports 'throw'
     /// expressions as well.
     /// </summary>
     internal abstract class AbstractUseThrowExpressionDiagnosticAnalyzer :
@@ -62,7 +62,7 @@ protected override void InitializeWorker(AnalysisContext context)
                 s_registerOperationActionInfo.Invoke(startContext, new object[]
                 {
                     new Action<OperationAnalysisContext>(operationContext => AnalyzeOperation(operationContext, expressionTypeOpt)),
-                    ImmutableArray.Create(OperationKind.ExpressionStatement)
+                    ImmutableArray.Create(OperationKind.ThrowExpression)
                 });
             });
         }
@@ -77,20 +77,21 @@ private void AnalyzeOperation(OperationAnalysisContext context, INamedTypeSymbol
 
             var cancellationToken = context.CancellationToken;
 
-            var throwOperation = (IExpressionStatement)context.Operation;
-            if (throwOperation.Expression.Kind != OperationKind.ThrowExpression)
+            var throwExpression = (IThrowExpression)context.Operation;
+            var throwStatementOperation = throwExpression.Parent;
+            if (throwStatementOperation.Kind != OperationKind.ExpressionStatement)
             {
                 return;
             }
 
-            var throwStatement = throwOperation.Syntax;
+            var throwStatement = throwExpression.Syntax;
             var options = context.Options;
             var optionSet = options.GetDocumentOptionSetAsync(syntaxTree, cancellationToken).GetAwaiter().GetResult();
             if (optionSet == null)
             {
                 return;
             }
-            
+
             var option = optionSet.GetOption(CodeStyleOptions.PreferThrowExpression, throwStatement.Language);
             if (!option.Value)
             {
@@ -106,7 +107,7 @@ private void AnalyzeOperation(OperationAnalysisContext context, INamedTypeSymbol
             }
 
             var ifOperation = GetContainingIfOperation(
-                semanticModel, throwOperation, cancellationToken);
+                semanticModel, (IExpressionStatement)throwStatementOperation, cancellationToken);
 
             // This throw statement isn't parented by an if-statement.  Nothing to
             // do here.
@@ -164,7 +165,7 @@ private void AnalyzeOperation(OperationAnalysisContext context, INamedTypeSymbol
 
             var allLocations = ImmutableArray.Create(
                 ifOperation.Syntax.GetLocation(),
-                ((IThrowExpression)throwOperation.Expression).Expression.Syntax.GetLocation(),
+                throwExpression.Expression.Syntax.GetLocation(),
                 assignmentExpression.Value.Syntax.GetLocation());
 
             var descriptor = GetDescriptorWithSeverity(option.Notification.Value);

From 9a91df6043b2a5b8074c86b6785fac85e222fc20 Mon Sep 17 00:00:00 2001
From: Heejae Chang <hechang@microsoft.com>
Date: Thu, 10 Aug 2017 13:27:21 -0700
Subject: [PATCH 35/77] moved every thing to IList

---
 .../InternalUtilities/EnumerableExtensions.cs | 15 ++++++++++
 .../AddUsing/AddUsingTests_NuGet.cs           |  6 ++--
 .../TodoCommentIncrementalAnalyzer.cs         |  6 ++--
 .../SymbolSearchUpdateEngineFactory.cs        | 14 ++++++----
 .../AddImport/AddImportTests_NuGet.vb         |  6 ++--
 ...pTodoCommentIncrementalAnalyzerProvider.cs |  2 +-
 .../AbstractAddImportFeatureService.cs        |  6 ++--
 .../AbstractAddImportFeatureService_Remote.cs |  6 ++--
 .../Remote/IRemoteAddImportFeatureService.cs  |  4 +--
 ...olReferenceFinder_PackageAssemblySearch.cs |  5 ++--
 .../IRemoteDesignerAttributeService.cs        |  2 +-
 .../AbstractDocumentHighlightsService.cs      |  6 ++--
 .../IRemoteDocumentHighlights.cs              |  4 +--
 .../AbstractNavigateToSearchService.Remote.cs | 10 ++++---
 .../IRemoteNavigateToSearchService.cs         |  4 +--
 .../AbstractTodoCommentService.cs             | 20 ++++++-------
 .../TodoComments/IRemoteTodoCommentService.cs |  2 +-
 .../TodoComments/ITodoCommentService.cs       |  2 +-
 ...cTodoCommentIncrementalAnalyzerProvider.vb |  2 +-
 .../DesignerAttributeIncrementalAnalyzer.cs   |  2 +-
 .../VisualStudioSymbolSearchService.cs        |  6 ++--
 .../DeclarationFinder_AllDeclarations.cs      |  9 +++---
 .../DeclarationFinder_SourceDeclarations.cs   | 13 +++++----
 .../FindSymbols/IRemoteSymbolFinder.cs        |  8 +++---
 .../IRemoteSymbolSearchUpdateEngine.cs        |  6 ++--
 .../SymbolSearch/ISymbolSearchService.cs      | 26 ++++++++---------
 .../Utilities/IReadOnlyListExtensions.cs      | 28 ++++++++++++++++++-
 .../Services/CodeAnalysisService_AddImport.cs | 16 +++++------
 .../CodeAnalysisService_DesignerAttributes.cs |  4 +--
 .../CodeAnalysisService_DocumentHighlights.cs |  2 +-
 .../CodeAnalysisService_NavigateTo.cs         |  4 +--
 .../CodeAnalysisService_SymbolFinder.cs       |  8 +++---
 .../CodeAnalysisService_TodoComments.cs       |  4 +--
 .../RemoteSymbolSearchUpdateEngine.cs         |  6 ++--
 34 files changed, 156 insertions(+), 108 deletions(-)

diff --git a/src/Compilers/Core/Portable/InternalUtilities/EnumerableExtensions.cs b/src/Compilers/Core/Portable/InternalUtilities/EnumerableExtensions.cs
index 08ac4dcd6c0c0..929f6ce36efa0 100644
--- a/src/Compilers/Core/Portable/InternalUtilities/EnumerableExtensions.cs
+++ b/src/Compilers/Core/Portable/InternalUtilities/EnumerableExtensions.cs
@@ -3,9 +3,11 @@
 using System;
 using System.Collections;
 using System.Collections.Generic;
+using System.Collections.Immutable;
 using System.Collections.ObjectModel;
 using System.Diagnostics;
 using System.Linq;
+using Microsoft.CodeAnalysis.PooledObjects;
 
 namespace Roslyn.Utilities
 {
@@ -242,6 +244,19 @@ public static IEnumerable<T> WhereNotNull<T>(this IEnumerable<T> source)
             return source.Where((Func<T, bool>)s_notNullTest);
         }
 
+        public static ImmutableArray<TResult> SelectAsArray<TSource, TResult>(this IEnumerable<TSource> source, Func<TSource, TResult> selector)
+        {
+            if (source == null)
+            {
+                return ImmutableArray<TResult>.Empty;
+            }
+
+            var builder = ArrayBuilder<TResult>.GetInstance();
+            builder.AddRange(source.Select(selector));
+
+            return builder.ToImmutableAndFree();
+        }
+
         public static bool All(this IEnumerable<bool> source)
         {
             if (source == null)
diff --git a/src/EditorFeatures/CSharpTest/AddUsing/AddUsingTests_NuGet.cs b/src/EditorFeatures/CSharpTest/AddUsing/AddUsingTests_NuGet.cs
index 1bd614d61dfd5..9d12f9d4f9cc0 100644
--- a/src/EditorFeatures/CSharpTest/AddUsing/AddUsingTests_NuGet.cs
+++ b/src/EditorFeatures/CSharpTest/AddUsing/AddUsingTests_NuGet.cs
@@ -257,7 +257,7 @@ public async Task TestFailedInstallRollsBackFile()
             installerServiceMock.Verify();
         }
 
-        private Task<IReadOnlyList<PackageWithTypeResult>> CreateSearchResult(
+        private Task<IList<PackageWithTypeResult>> CreateSearchResult(
             string packageName, string typeName, ImmutableArray<string> containingNamespaceNames)
         {
             return CreateSearchResult(new PackageWithTypeResult(
@@ -265,8 +265,8 @@ public async Task TestFailedInstallRollsBackFile()
                 rank: 0, containingNamespaceNames: containingNamespaceNames));
         }
 
-        private Task<IReadOnlyList<PackageWithTypeResult>> CreateSearchResult(params PackageWithTypeResult[] results)
-            => Task.FromResult<IReadOnlyList<PackageWithTypeResult>>(ImmutableArray.Create(results));
+        private Task<IList<PackageWithTypeResult>> CreateSearchResult(params PackageWithTypeResult[] results)
+            => Task.FromResult<IList<PackageWithTypeResult>>(ImmutableArray.Create(results));
 
         private ImmutableArray<string> CreateNameParts(params string[] parts) => parts.ToImmutableArray();
     }
diff --git a/src/EditorFeatures/Core/Implementation/TodoComment/TodoCommentIncrementalAnalyzer.cs b/src/EditorFeatures/Core/Implementation/TodoComment/TodoCommentIncrementalAnalyzer.cs
index 86611f7f28087..466004e770769 100644
--- a/src/EditorFeatures/Core/Implementation/TodoComment/TodoCommentIncrementalAnalyzer.cs
+++ b/src/EditorFeatures/Core/Implementation/TodoComment/TodoCommentIncrementalAnalyzer.cs
@@ -87,19 +87,19 @@ public async Task AnalyzeSyntaxAsync(Document document, InvocationReasons reason
             }
         }
 
-        private async Task<IReadOnlyList<TodoComment>> GetTodoCommentsAsync(Document document, IReadOnlyList<TodoCommentDescriptor> tokens, CancellationToken cancellationToken)
+        private async Task<IList<TodoComment>> GetTodoCommentsAsync(Document document, IList<TodoCommentDescriptor> tokens, CancellationToken cancellationToken)
         {
             var service = document.GetLanguageService<ITodoCommentService>();
             if (service == null)
             {
                 // no inproc support
-                return SpecializedCollections.EmptyReadOnlyList<TodoComment>();
+                return SpecializedCollections.EmptyList<TodoComment>();
             }
 
             return await service.GetTodoCommentsAsync(document, tokens, cancellationToken).ConfigureAwait(false);
         }
 
-        private async Task<ImmutableArray<TodoItem>> CreateItemsAsync(Document document, IReadOnlyList<TodoComment> comments, CancellationToken cancellationToken)
+        private async Task<ImmutableArray<TodoItem>> CreateItemsAsync(Document document, IList<TodoComment> comments, CancellationToken cancellationToken)
         {
             var items = ImmutableArray.CreateBuilder<TodoItem>();
             if (comments != null)
diff --git a/src/EditorFeatures/Core/SymbolSearch/SymbolSearchUpdateEngineFactory.cs b/src/EditorFeatures/Core/SymbolSearch/SymbolSearchUpdateEngineFactory.cs
index b7d0888c0281e..c76757b729e68 100644
--- a/src/EditorFeatures/Core/SymbolSearch/SymbolSearchUpdateEngineFactory.cs
+++ b/src/EditorFeatures/Core/SymbolSearch/SymbolSearchUpdateEngineFactory.cs
@@ -1,9 +1,11 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
+using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.Remote;
+using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.SymbolSearch
 {
@@ -61,31 +63,31 @@ private partial class RemoteUpdateEngine : ISymbolSearchUpdateEngine, ISymbolSea
             public async Task<ImmutableArray<PackageWithTypeResult>> FindPackagesWithTypeAsync(
                 string source, string name, int arity, CancellationToken cancellationToken)
             {
-                var results = await _session.TryInvokeAsync<ImmutableArray<PackageWithTypeResult>>(
+                var results = await _session.TryInvokeAsync<IList<PackageWithTypeResult>>(
                     nameof(IRemoteSymbolSearchUpdateEngine.FindPackagesWithTypeAsync),
                     new object[] { source, name, arity }, cancellationToken).ConfigureAwait(false);
 
-                return results.NullToEmpty();
+                return results.ToImmutableArrayOrEmpty();
             }
 
             public async Task<ImmutableArray<PackageWithAssemblyResult>> FindPackagesWithAssemblyAsync(
                 string source, string assemblyName, CancellationToken cancellationToken)
             {
-                var results = await _session.TryInvokeAsync<ImmutableArray<PackageWithAssemblyResult>>(
+                var results = await _session.TryInvokeAsync<IList<PackageWithAssemblyResult>>(
                     nameof(IRemoteSymbolSearchUpdateEngine.FindPackagesWithAssemblyAsync),
                     new object[] { source, assemblyName }, cancellationToken).ConfigureAwait(false);
 
-                return results.NullToEmpty();
+                return results.ToImmutableArrayOrEmpty();
             }
 
             public async Task<ImmutableArray<ReferenceAssemblyWithTypeResult>> FindReferenceAssembliesWithTypeAsync(
                 string name, int arity, CancellationToken cancellationToken)
             {
-                var results = await _session.TryInvokeAsync<ImmutableArray<ReferenceAssemblyWithTypeResult>>(
+                var results = await _session.TryInvokeAsync<IList<ReferenceAssemblyWithTypeResult>>(
                     nameof(IRemoteSymbolSearchUpdateEngine.FindReferenceAssembliesWithTypeAsync),
                     new object[] { name, arity }, cancellationToken).ConfigureAwait(false);
 
-                return results.NullToEmpty();
+                return results.ToImmutableArrayOrEmpty();
             }
 
             public async Task UpdateContinuouslyAsync(
diff --git a/src/EditorFeatures/VisualBasicTest/Diagnostics/AddImport/AddImportTests_NuGet.vb b/src/EditorFeatures/VisualBasicTest/Diagnostics/AddImport/AddImportTests_NuGet.vb
index b2fb56157de3f..b0d626ebda015 100644
--- a/src/EditorFeatures/VisualBasicTest/Diagnostics/AddImport/AddImportTests_NuGet.vb
+++ b/src/EditorFeatures/VisualBasicTest/Diagnostics/AddImport/AddImportTests_NuGet.vb
@@ -239,7 +239,7 @@ End Class", fixProviderData:=New ProviderData(installerServiceMock.Object, packa
             installerServiceMock.Verify()
         End Function
 
-        Private Function CreateSearchResult(packageName As String, typeName As String, nameParts As ImmutableArray(Of String)) As Task(Of IReadOnlyList(Of PackageWithTypeResult))
+        Private Function CreateSearchResult(packageName As String, typeName As String, nameParts As ImmutableArray(Of String)) As Task(Of IList(Of PackageWithTypeResult))
             Return CreateSearchResult(New PackageWithTypeResult(
                 packageName:=packageName,
                 typeName:=typeName,
@@ -248,8 +248,8 @@ End Class", fixProviderData:=New ProviderData(installerServiceMock.Object, packa
                 containingNamespaceNames:=nameParts))
         End Function
 
-        Private Function CreateSearchResult(ParamArray results As PackageWithTypeResult()) As Task(Of IReadOnlyList(Of PackageWithTypeResult))
-            Return Task.FromResult(Of IReadOnlyList(Of PackageWithTypeResult))(ImmutableArray.Create(results))
+        Private Function CreateSearchResult(ParamArray results As PackageWithTypeResult()) As Task(Of IList(Of PackageWithTypeResult))
+            Return Task.FromResult(Of IList(Of PackageWithTypeResult))(ImmutableArray.Create(results))
         End Function
 
         Private Function CreateNameParts(ParamArray parts As String()) As ImmutableArray(Of String)
diff --git a/src/Features/CSharp/Portable/TodoComments/CSharpTodoCommentIncrementalAnalyzerProvider.cs b/src/Features/CSharp/Portable/TodoComments/CSharpTodoCommentIncrementalAnalyzerProvider.cs
index 6ec91af8f23bb..a2fca9fda9b74 100644
--- a/src/Features/CSharp/Portable/TodoComments/CSharpTodoCommentIncrementalAnalyzerProvider.cs
+++ b/src/Features/CSharp/Portable/TodoComments/CSharpTodoCommentIncrementalAnalyzerProvider.cs
@@ -28,7 +28,7 @@ public CSharpTodoCommentService(Workspace workspace) : base(workspace)
         {
         }
 
-        protected override void AppendTodoComments(IReadOnlyList<TodoCommentDescriptor> commentDescriptors, SyntacticDocument document, SyntaxTrivia trivia, List<TodoComment> todoList)
+        protected override void AppendTodoComments(IList<TodoCommentDescriptor> commentDescriptors, SyntacticDocument document, SyntaxTrivia trivia, List<TodoComment> todoList)
         {
             if (PreprocessorHasComment(trivia))
             {
diff --git a/src/Features/Core/Portable/AddImport/AbstractAddImportFeatureService.cs b/src/Features/Core/Portable/AddImport/AbstractAddImportFeatureService.cs
index f591a7a63ef7b..7b8b5ce36878e 100644
--- a/src/Features/Core/Portable/AddImport/AbstractAddImportFeatureService.cs
+++ b/src/Features/Core/Portable/AddImport/AbstractAddImportFeatureService.cs
@@ -61,7 +61,7 @@ protected AbstractAddImportFeatureService()
             if (RemoteSupportedLanguages.IsSupported(document.Project.Language))
             {
                 var callbackTarget = new RemoteSymbolSearchService(symbolSearchService, cancellationToken);
-                var result = await document.Project.Solution.TryRunCodeAnalysisRemoteAsync<ImmutableArray<AddImportFixData>>(
+                var result = await document.Project.Solution.TryRunCodeAnalysisRemoteAsync<IList<AddImportFixData>>(
                     RemoteFeatureOptions.AddImportEnabled,
                     callbackTarget,
                     nameof(IRemoteAddImportFeatureService.GetFixesAsync),
@@ -78,9 +78,9 @@ protected AbstractAddImportFeatureService()
 
                 var documentOptions = await document.GetOptionsAsync(cancellationToken).ConfigureAwait(false);
 
-                if (!result.IsDefault)
+                if (result != null)
                 {
-                    return result;
+                    return result.ToImmutableArray();
                 }
             }
 
diff --git a/src/Features/Core/Portable/AddImport/Remote/AbstractAddImportFeatureService_Remote.cs b/src/Features/Core/Portable/AddImport/Remote/AbstractAddImportFeatureService_Remote.cs
index 3a236ddf729c0..8fa8bf9509476 100644
--- a/src/Features/Core/Portable/AddImport/Remote/AbstractAddImportFeatureService_Remote.cs
+++ b/src/Features/Core/Portable/AddImport/Remote/AbstractAddImportFeatureService_Remote.cs
@@ -40,21 +40,21 @@ public Task UpdateContinuouslyAsync(string sourceName, string localSettingsDirec
                 throw new NotImplementedException();
             }
 
-            public Task<IReadOnlyList<PackageWithTypeResult>> FindPackagesWithTypeAsync(
+            public Task<IList<PackageWithTypeResult>> FindPackagesWithTypeAsync(
                 string source, string name, int arity, CancellationToken cancellationToken)
             {
                 return _symbolSearchService.FindPackagesWithTypeAsync(
                     source, name, arity, cancellationToken);
             }
 
-            public Task<IReadOnlyList<PackageWithAssemblyResult>> FindPackagesWithAssemblyAsync(
+            public Task<IList<PackageWithAssemblyResult>> FindPackagesWithAssemblyAsync(
                 string source, string name, CancellationToken cancellationToken)
             {
                 return _symbolSearchService.FindPackagesWithAssemblyAsync(
                     source, name, cancellationToken);
             }
 
-            public Task<IReadOnlyList<ReferenceAssemblyWithTypeResult>> FindReferenceAssembliesWithTypeAsync(
+            public Task<IList<ReferenceAssemblyWithTypeResult>> FindReferenceAssembliesWithTypeAsync(
                 string name, int arity, CancellationToken cancellationToken)
             {
                 return _symbolSearchService.FindReferenceAssembliesWithTypeAsync(
diff --git a/src/Features/Core/Portable/AddImport/Remote/IRemoteAddImportFeatureService.cs b/src/Features/Core/Portable/AddImport/Remote/IRemoteAddImportFeatureService.cs
index f1d93472c9f31..5fff125b7ef9a 100644
--- a/src/Features/Core/Portable/AddImport/Remote/IRemoteAddImportFeatureService.cs
+++ b/src/Features/Core/Portable/AddImport/Remote/IRemoteAddImportFeatureService.cs
@@ -11,8 +11,8 @@ namespace Microsoft.CodeAnalysis.AddImport
 {
     internal interface IRemoteAddImportFeatureService
     {
-        Task<IReadOnlyList<AddImportFixData>> GetFixesAsync(
+        Task<IList<AddImportFixData>> GetFixesAsync(
             DocumentId documentId, TextSpan span, string diagnosticId, bool placeSystemNamespaceFirst,
-            bool searchReferenceAssemblies, IReadOnlyList<PackageSource> packageSources, CancellationToken cancellationToken);
+            bool searchReferenceAssemblies, IList<PackageSource> packageSources, CancellationToken cancellationToken);
     }
 }
diff --git a/src/Features/Core/Portable/AddImport/SymbolReferenceFinder_PackageAssemblySearch.cs b/src/Features/Core/Portable/AddImport/SymbolReferenceFinder_PackageAssemblySearch.cs
index a2bc71f0cd822..7ab3d06324af3 100644
--- a/src/Features/Core/Portable/AddImport/SymbolReferenceFinder_PackageAssemblySearch.cs
+++ b/src/Features/Core/Portable/AddImport/SymbolReferenceFinder_PackageAssemblySearch.cs
@@ -5,6 +5,7 @@
 using Microsoft.CodeAnalysis.Packaging;
 using Microsoft.CodeAnalysis.PooledObjects;
 using Microsoft.CodeAnalysis.SymbolSearch;
+using Microsoft.CodeAnalysis.Utilities;
 using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.AddImport
@@ -163,7 +164,7 @@ private partial class SymbolReferenceFinder
 
                 var desiredName = GetDesiredName(isAttributeSearch, result.TypeName);
                 allReferences.Add(new AssemblyReference(
-                    _owner, new SearchResult(desiredName, nameNode, result.ContainingNamespaceNames, weight), result));
+                    _owner, new SearchResult(desiredName, nameNode, result.ContainingNamespaceNames.ToReadOnlyList(), weight), result));
             }
 
             private void HandleNugetReference(
@@ -177,7 +178,7 @@ private partial class SymbolReferenceFinder
             {
                 var desiredName = GetDesiredName(isAttributeSearch, result.TypeName);
                 allReferences.Add(new PackageReference(_owner,
-                    new SearchResult(desiredName, nameNode, result.ContainingNamespaceNames, weight),
+                    new SearchResult(desiredName, nameNode, result.ContainingNamespaceNames.ToReadOnlyList(), weight),
                     source, result.PackageName, result.Version));
             }
 
diff --git a/src/Features/Core/Portable/DesignerAttributes/IRemoteDesignerAttributeService.cs b/src/Features/Core/Portable/DesignerAttributes/IRemoteDesignerAttributeService.cs
index bd4076c010c78..3f09f0a062bc9 100644
--- a/src/Features/Core/Portable/DesignerAttributes/IRemoteDesignerAttributeService.cs
+++ b/src/Features/Core/Portable/DesignerAttributes/IRemoteDesignerAttributeService.cs
@@ -8,6 +8,6 @@ namespace Microsoft.CodeAnalysis.DesignerAttributes
 {
     internal interface IRemoteDesignerAttributeService
     {
-        Task<IReadOnlyList<DesignerAttributeDocumentData>> ScanDesignerAttributesAsync(ProjectId projectId, CancellationToken cancellationToken);
+        Task<IList<DesignerAttributeDocumentData>> ScanDesignerAttributesAsync(ProjectId projectId, CancellationToken cancellationToken);
     }
 }
diff --git a/src/Features/Core/Portable/DocumentHighlighting/AbstractDocumentHighlightsService.cs b/src/Features/Core/Portable/DocumentHighlighting/AbstractDocumentHighlightsService.cs
index 5d78c9d79f7ca..d8a5ad324e172 100644
--- a/src/Features/Core/Portable/DocumentHighlighting/AbstractDocumentHighlightsService.cs
+++ b/src/Features/Core/Portable/DocumentHighlighting/AbstractDocumentHighlightsService.cs
@@ -39,7 +39,7 @@ internal abstract partial class AbstractDocumentHighlightsService : IDocumentHig
         private async Task<(bool succeeded, ImmutableArray<DocumentHighlights> highlights)> GetDocumentHighlightsInRemoteProcessAsync(
             Document document, int position, IImmutableSet<Document> documentsToSearch, CancellationToken cancellationToken)
         {
-            var result = await document.Project.Solution.TryRunCodeAnalysisRemoteAsync<ImmutableArray<SerializableDocumentHighlights>>(
+            var result = await document.Project.Solution.TryRunCodeAnalysisRemoteAsync<IList<SerializableDocumentHighlights>>(
                 RemoteFeatureOptions.DocumentHighlightingEnabled,
                 nameof(IRemoteDocumentHighlights.GetDocumentHighlightsAsync),
                 new object[]
@@ -50,12 +50,12 @@ internal abstract partial class AbstractDocumentHighlightsService : IDocumentHig
                 },
                 cancellationToken).ConfigureAwait(false);
 
-            if (result.IsDefault)
+            if (result == null)
             {
                 return (succeeded: false, ImmutableArray<DocumentHighlights>.Empty);
             }
 
-            return (true, result.SelectAsArray(h => h.Rehydrate(document.Project.Solution)));
+            return (true, result.Select(h => h.Rehydrate(document.Project.Solution)).ToImmutableArray());
         }
 
         private async Task<ImmutableArray<DocumentHighlights>> GetDocumentHighlightsInCurrentProcessAsync(
diff --git a/src/Features/Core/Portable/DocumentHighlighting/IRemoteDocumentHighlights.cs b/src/Features/Core/Portable/DocumentHighlighting/IRemoteDocumentHighlights.cs
index 4078b4082413a..df95e87c8fe14 100644
--- a/src/Features/Core/Portable/DocumentHighlighting/IRemoteDocumentHighlights.cs
+++ b/src/Features/Core/Portable/DocumentHighlighting/IRemoteDocumentHighlights.cs
@@ -10,14 +10,14 @@ namespace Microsoft.CodeAnalysis.DocumentHighlighting
 {
     internal interface IRemoteDocumentHighlights
     {
-        Task<IReadOnlyList<SerializableDocumentHighlights>> GetDocumentHighlightsAsync(
+        Task<IList<SerializableDocumentHighlights>> GetDocumentHighlightsAsync(
             DocumentId documentId, int position, DocumentId[] documentIdsToSearch, CancellationToken cancellationToken);
     }
 
     internal struct SerializableDocumentHighlights
     {
         public DocumentId DocumentId;
-        public IReadOnlyList<HighlightSpan> HighlightSpans;
+        public IList<HighlightSpan> HighlightSpans;
 
         public DocumentHighlights Rehydrate(Solution solution)
             => new DocumentHighlights(solution.GetDocument(DocumentId), HighlightSpans.ToImmutableArray());
diff --git a/src/Features/Core/Portable/NavigateTo/AbstractNavigateToSearchService.Remote.cs b/src/Features/Core/Portable/NavigateTo/AbstractNavigateToSearchService.Remote.cs
index 55e53c71ee74a..f7bf8a75e7677 100644
--- a/src/Features/Core/Portable/NavigateTo/AbstractNavigateToSearchService.Remote.cs
+++ b/src/Features/Core/Portable/NavigateTo/AbstractNavigateToSearchService.Remote.cs
@@ -1,12 +1,14 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
 using System;
+using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.Experiments;
 using Microsoft.CodeAnalysis.Remote;
+using Roslyn.Utilities;
 
 namespace Microsoft.CodeAnalysis.NavigateTo
 {
@@ -17,11 +19,11 @@ internal abstract partial class AbstractNavigateToSearchService
         {
             var solution = document.Project.Solution;
 
-            var serializableResults = await client.TryRunCodeAnalysisRemoteAsync<ImmutableArray<SerializableNavigateToSearchResult>>(
+            var serializableResults = await client.TryRunCodeAnalysisRemoteAsync<IList<SerializableNavigateToSearchResult>>(
                 solution, nameof(IRemoteNavigateToSearchService.SearchDocumentAsync),
                 new object[] { document.Id, searchPattern }, cancellationToken).ConfigureAwait(false);
 
-            return serializableResults.NullToEmpty().SelectAsArray(r => r.Rehydrate(solution));
+            return serializableResults.SelectAsArray(r => r.Rehydrate(solution));
         }
 
         private async Task<ImmutableArray<INavigateToSearchResult>> SearchProjectInRemoteProcessAsync(
@@ -29,11 +31,11 @@ internal abstract partial class AbstractNavigateToSearchService
         {
             var solution = project.Solution;
 
-            var serializableResults = await client.TryRunCodeAnalysisRemoteAsync<ImmutableArray<SerializableNavigateToSearchResult>>(
+            var serializableResults = await client.TryRunCodeAnalysisRemoteAsync<IList<SerializableNavigateToSearchResult>>(
                 solution, nameof(IRemoteNavigateToSearchService.SearchProjectAsync),
                 new object[] { project.Id, searchPattern }, cancellationToken).ConfigureAwait(false);
 
-            return serializableResults.NullToEmpty().SelectAsArray(r => r.Rehydrate(solution));
+            return serializableResults.SelectAsArray(r => r.Rehydrate(solution));
         }
 
         private static async Task<RemoteHostClient> TryGetRemoteHostClientAsync(Project project, CancellationToken cancellationToken)
diff --git a/src/Features/Core/Portable/NavigateTo/IRemoteNavigateToSearchService.cs b/src/Features/Core/Portable/NavigateTo/IRemoteNavigateToSearchService.cs
index cf1089e29eb96..16f5a09bd0715 100644
--- a/src/Features/Core/Portable/NavigateTo/IRemoteNavigateToSearchService.cs
+++ b/src/Features/Core/Portable/NavigateTo/IRemoteNavigateToSearchService.cs
@@ -10,7 +10,7 @@ namespace Microsoft.CodeAnalysis.NavigateTo
 {
     internal interface IRemoteNavigateToSearchService
     {
-        Task<IReadOnlyList<SerializableNavigateToSearchResult>> SearchDocumentAsync(DocumentId documentId, string searchPattern, CancellationToken cancellationToken);
-        Task<IReadOnlyList<SerializableNavigateToSearchResult>> SearchProjectAsync(ProjectId projectId, string searchPattern, CancellationToken cancellationToken);
+        Task<IList<SerializableNavigateToSearchResult>> SearchDocumentAsync(DocumentId documentId, string searchPattern, CancellationToken cancellationToken);
+        Task<IList<SerializableNavigateToSearchResult>> SearchProjectAsync(ProjectId projectId, string searchPattern, CancellationToken cancellationToken);
     }
 }
diff --git a/src/Features/Core/Portable/TodoComments/AbstractTodoCommentService.cs b/src/Features/Core/Portable/TodoComments/AbstractTodoCommentService.cs
index a45cef7e5f114..d4eeb07e6259e 100644
--- a/src/Features/Core/Portable/TodoComments/AbstractTodoCommentService.cs
+++ b/src/Features/Core/Portable/TodoComments/AbstractTodoCommentService.cs
@@ -36,9 +36,9 @@ protected AbstractTodoCommentService(Workspace workspace)
 
         protected abstract string GetNormalizedText(string message);
         protected abstract int GetCommentStartingIndex(string message);
-        protected abstract void AppendTodoComments(IReadOnlyList<TodoCommentDescriptor> commentDescriptors, SyntacticDocument document, SyntaxTrivia trivia, List<TodoComment> todoList);
+        protected abstract void AppendTodoComments(IList<TodoCommentDescriptor> commentDescriptors, SyntacticDocument document, SyntaxTrivia trivia, List<TodoComment> todoList);
 
-        public async Task<IReadOnlyList<TodoComment>> GetTodoCommentsAsync(Document document, IReadOnlyList<TodoCommentDescriptor> commentDescriptors, CancellationToken cancellationToken)
+        public async Task<IList<TodoComment>> GetTodoCommentsAsync(Document document, IList<TodoCommentDescriptor> commentDescriptors, CancellationToken cancellationToken)
         {
             // make sure given input is right one
             Contract.ThrowIfFalse(_workspace == document.Project.Solution.Workspace);
@@ -58,17 +58,17 @@ public async Task<IReadOnlyList<TodoComment>> GetTodoCommentsAsync(Document docu
             return await GetTodoCommentsInCurrentProcessAsync(document, commentDescriptors, cancellationToken).ConfigureAwait(false);
         }
 
-        private async Task<IReadOnlyList<TodoComment>> GetTodoCommentsInRemoteHostAsync(
-            RemoteHostClient client, Document document, IReadOnlyList<TodoCommentDescriptor> commentDescriptors, CancellationToken cancellationToken)
+        private async Task<IList<TodoComment>> GetTodoCommentsInRemoteHostAsync(
+            RemoteHostClient client, Document document, IList<TodoCommentDescriptor> commentDescriptors, CancellationToken cancellationToken)
         {
             var keepAliveSession = await TryGetKeepAliveSessionAsync(client, cancellationToken).ConfigureAwait(false);
 
-            var result = await keepAliveSession.TryInvokeAsync<IReadOnlyList<TodoComment>>(
+            var result = await keepAliveSession.TryInvokeAsync<IList<TodoComment>>(
                 nameof(IRemoteTodoCommentService.GetTodoCommentsAsync),
                 document.Project.Solution,
                 new object[] { document.Id, commentDescriptors }, cancellationToken).ConfigureAwait(false);
 
-            return result ?? SpecializedCollections.EmptyReadOnlyList<TodoComment>();
+            return result ?? SpecializedCollections.EmptyList<TodoComment>();
         }
 
         private async Task<KeepAliveSession> TryGetKeepAliveSessionAsync(RemoteHostClient client, CancellationToken cancellationToken)
@@ -84,8 +84,8 @@ private async Task<KeepAliveSession> TryGetKeepAliveSessionAsync(RemoteHostClien
             }
         }
 
-        private async Task<IReadOnlyList<TodoComment>> GetTodoCommentsInCurrentProcessAsync(
-            Document document, IReadOnlyList<TodoCommentDescriptor> commentDescriptors, CancellationToken cancellationToken)
+        private async Task<IList<TodoComment>> GetTodoCommentsInCurrentProcessAsync(
+            Document document, IList<TodoCommentDescriptor> commentDescriptors, CancellationToken cancellationToken)
         {
             cancellationToken.ThrowIfCancellationRequested();
 
@@ -115,7 +115,7 @@ private bool ContainsComments(SyntaxTrivia trivia)
             return PreprocessorHasComment(trivia) || IsSingleLineComment(trivia) || IsMultilineComment(trivia);
         }
 
-        protected void AppendTodoCommentInfoFromSingleLine(IReadOnlyList<TodoCommentDescriptor> commentDescriptors, SyntacticDocument document, string message, int start, List<TodoComment> todoList)
+        protected void AppendTodoCommentInfoFromSingleLine(IList<TodoCommentDescriptor> commentDescriptors, SyntacticDocument document, string message, int start, List<TodoComment> todoList)
         {
             var index = GetCommentStartingIndex(message);
             if (index >= message.Length)
@@ -147,7 +147,7 @@ protected void AppendTodoCommentInfoFromSingleLine(IReadOnlyList<TodoCommentDesc
             }
         }
 
-        protected void ProcessMultilineComment(IReadOnlyList<TodoCommentDescriptor> commentDescriptors, SyntacticDocument document, SyntaxTrivia trivia, int postfixLength, List<TodoComment> todoList)
+        protected void ProcessMultilineComment(IList<TodoCommentDescriptor> commentDescriptors, SyntacticDocument document, SyntaxTrivia trivia, int postfixLength, List<TodoComment> todoList)
         {
             // this is okay since we know it is already alive
             var text = document.Text;
diff --git a/src/Features/Core/Portable/TodoComments/IRemoteTodoCommentService.cs b/src/Features/Core/Portable/TodoComments/IRemoteTodoCommentService.cs
index c65172d3f1032..c518327f06a39 100644
--- a/src/Features/Core/Portable/TodoComments/IRemoteTodoCommentService.cs
+++ b/src/Features/Core/Portable/TodoComments/IRemoteTodoCommentService.cs
@@ -13,6 +13,6 @@ namespace Microsoft.CodeAnalysis.TodoComments
     /// </summary>
     internal interface IRemoteTodoCommentService
     {
-        Task<IReadOnlyList<TodoComment>> GetTodoCommentsAsync(PinnedSolutionInfo solutionInfo, DocumentId documentId, IReadOnlyList<TodoCommentDescriptor> commentDescriptors, CancellationToken cancellationToken);
+        Task<IList<TodoComment>> GetTodoCommentsAsync(PinnedSolutionInfo solutionInfo, DocumentId documentId, IList<TodoCommentDescriptor> commentDescriptors, CancellationToken cancellationToken);
     }
 }
diff --git a/src/Features/Core/Portable/TodoComments/ITodoCommentService.cs b/src/Features/Core/Portable/TodoComments/ITodoCommentService.cs
index 3a378b5b409c6..e6a3689445361 100644
--- a/src/Features/Core/Portable/TodoComments/ITodoCommentService.cs
+++ b/src/Features/Core/Portable/TodoComments/ITodoCommentService.cs
@@ -42,6 +42,6 @@ public TodoComment(TodoCommentDescriptor descriptor, string message, int positio
 
     internal interface ITodoCommentService : ILanguageService
     {
-        Task<IReadOnlyList<TodoComment>> GetTodoCommentsAsync(Document document, IReadOnlyList<TodoCommentDescriptor> commentDescriptors, CancellationToken cancellationToken);
+        Task<IList<TodoComment>> GetTodoCommentsAsync(Document document, IList<TodoCommentDescriptor> commentDescriptors, CancellationToken cancellationToken);
     }
 }
diff --git a/src/Features/VisualBasic/Portable/TodoComments/BasicTodoCommentIncrementalAnalyzerProvider.vb b/src/Features/VisualBasic/Portable/TodoComments/BasicTodoCommentIncrementalAnalyzerProvider.vb
index dbcdfe3003f11..cca5bb7ea250e 100644
--- a/src/Features/VisualBasic/Portable/TodoComments/BasicTodoCommentIncrementalAnalyzerProvider.vb
+++ b/src/Features/VisualBasic/Portable/TodoComments/BasicTodoCommentIncrementalAnalyzerProvider.vb
@@ -25,7 +25,7 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.TodoComments
             MyBase.New(workspace)
         End Sub
 
-        Protected Overrides Sub AppendTodoComments(commentDescriptors As IReadOnlyList(Of TodoCommentDescriptor), document As SyntacticDocument, trivia As SyntaxTrivia, todoList As List(Of TodoComment))
+        Protected Overrides Sub AppendTodoComments(commentDescriptors As IList(Of TodoCommentDescriptor), document As SyntacticDocument, trivia As SyntaxTrivia, todoList As List(Of TodoComment))
             If PreprocessorHasComment(trivia) Then
                 Dim commentTrivia = trivia.GetStructure().DescendantTrivia().First(Function(t) t.RawKind = SyntaxKind.CommentTrivia)
 
diff --git a/src/VisualStudio/Core/Def/Implementation/DesignerAttribute/DesignerAttributeIncrementalAnalyzer.cs b/src/VisualStudio/Core/Def/Implementation/DesignerAttribute/DesignerAttributeIncrementalAnalyzer.cs
index 7dd8ee8705d5b..6ceaa77b5d7b7 100644
--- a/src/VisualStudio/Core/Def/Implementation/DesignerAttribute/DesignerAttributeIncrementalAnalyzer.cs
+++ b/src/VisualStudio/Core/Def/Implementation/DesignerAttribute/DesignerAttributeIncrementalAnalyzer.cs
@@ -130,7 +130,7 @@ public async Task AnalyzeProjectAsync(Project project, bool semanticsChanged, In
                     return null;
                 }
 
-                var serializedResults = await session.InvokeAsync<IReadOnlyList<DesignerAttributeDocumentData>>(
+                var serializedResults = await session.InvokeAsync<IList<DesignerAttributeDocumentData>>(
                     nameof(IRemoteDesignerAttributeService.ScanDesignerAttributesAsync), new object[] { project.Id }, cancellationToken).ConfigureAwait(false);
 
                 var data = serializedResults.ToImmutableDictionary(kvp => kvp.FilePath);
diff --git a/src/VisualStudio/Core/Def/SymbolSearch/VisualStudioSymbolSearchService.cs b/src/VisualStudio/Core/Def/SymbolSearch/VisualStudioSymbolSearchService.cs
index 6b7f9d79befc6..ccd06a3f2eee0 100644
--- a/src/VisualStudio/Core/Def/SymbolSearch/VisualStudioSymbolSearchService.cs
+++ b/src/VisualStudio/Core/Def/SymbolSearch/VisualStudioSymbolSearchService.cs
@@ -108,7 +108,7 @@ private async Task UpdateSourceInBackgroundAsync(string sourceName)
             await engine.UpdateContinuouslyAsync(sourceName, _localSettingsDirectory).ConfigureAwait(false);
         }
 
-        public async Task<IReadOnlyList<PackageWithTypeResult>> FindPackagesWithTypeAsync(
+        public async Task<IList<PackageWithTypeResult>> FindPackagesWithTypeAsync(
             string source, string name, int arity, CancellationToken cancellationToken)
         {
             var engine = await GetEngine(cancellationToken).ConfigureAwait(false);
@@ -118,7 +118,7 @@ private async Task UpdateSourceInBackgroundAsync(string sourceName)
             return FilterAndOrderPackages(allPackagesWithType);
         }
 
-        public async Task<IReadOnlyList<PackageWithAssemblyResult>> FindPackagesWithAssemblyAsync(
+        public async Task<IList<PackageWithAssemblyResult>> FindPackagesWithAssemblyAsync(
             string source, string assemblyName, CancellationToken cancellationToken)
         {
             var engine = await GetEngine(cancellationToken).ConfigureAwait(false);
@@ -170,7 +170,7 @@ private async Task UpdateSourceInBackgroundAsync(string sourceName)
             return result.ToImmutableAndFree();
         }
 
-        public async Task<IReadOnlyList<ReferenceAssemblyWithTypeResult>> FindReferenceAssembliesWithTypeAsync(
+        public async Task<IList<ReferenceAssemblyWithTypeResult>> FindReferenceAssembliesWithTypeAsync(
             string name, int arity, CancellationToken cancellationToken)
         {
             var engine = await GetEngine(cancellationToken).ConfigureAwait(false);
diff --git a/src/Workspaces/Core/Portable/FindSymbols/Declarations/DeclarationFinder_AllDeclarations.cs b/src/Workspaces/Core/Portable/FindSymbols/Declarations/DeclarationFinder_AllDeclarations.cs
index 5804518b3d3d2..2619fdcc5cef6 100644
--- a/src/Workspaces/Core/Portable/FindSymbols/Declarations/DeclarationFinder_AllDeclarations.cs
+++ b/src/Workspaces/Core/Portable/FindSymbols/Declarations/DeclarationFinder_AllDeclarations.cs
@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
 using System;
+using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Diagnostics;
 using System.Threading;
@@ -99,12 +100,12 @@ internal static partial class DeclarationFinder
                 return (false, ImmutableArray<SymbolAndProjectId>.Empty);
             }
 
-            var result = await project.Solution.TryRunCodeAnalysisRemoteAsync<ImmutableArray<SerializableSymbolAndProjectId>>(
+            var result = await project.Solution.TryRunCodeAnalysisRemoteAsync<IList<SerializableSymbolAndProjectId>>(
                 RemoteFeatureOptions.SymbolFinderEnabled,
                 nameof(IRemoteSymbolFinder.FindAllDeclarationsWithNormalQueryAsync),
                 new object[] { project.Id, query.Name, query.Kind, criteria }, cancellationToken).ConfigureAwait(false);
 
-            if (result.IsDefault)
+            if (result == null)
             {
                 return (false, ImmutableArray<SymbolAndProjectId>.Empty);
             }
@@ -116,9 +117,9 @@ internal static partial class DeclarationFinder
         }
 
         private static async Task<ImmutableArray<SymbolAndProjectId>> RehydrateAsync(
-            Solution solution, ImmutableArray<SerializableSymbolAndProjectId> array, CancellationToken cancellationToken)
+            Solution solution, IList<SerializableSymbolAndProjectId> array, CancellationToken cancellationToken)
         {
-            var result = ArrayBuilder<SymbolAndProjectId>.GetInstance(array.Length);
+            var result = ArrayBuilder<SymbolAndProjectId>.GetInstance(array.Count);
 
             foreach (var dehydrated in array)
             {
diff --git a/src/Workspaces/Core/Portable/FindSymbols/Declarations/DeclarationFinder_SourceDeclarations.cs b/src/Workspaces/Core/Portable/FindSymbols/Declarations/DeclarationFinder_SourceDeclarations.cs
index 60b80e14e5369..1f915167d00eb 100644
--- a/src/Workspaces/Core/Portable/FindSymbols/Declarations/DeclarationFinder_SourceDeclarations.cs
+++ b/src/Workspaces/Core/Portable/FindSymbols/Declarations/DeclarationFinder_SourceDeclarations.cs
@@ -1,6 +1,7 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
 using System;
+using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Threading;
 using System.Threading.Tasks;
@@ -115,12 +116,12 @@ internal static partial class DeclarationFinder
         private static async Task<(bool, ImmutableArray<SymbolAndProjectId>)> TryFindSourceDeclarationsWithNormalQueryInRemoteProcessAsync(
             Solution solution, string name, bool ignoreCase, SymbolFilter criteria, CancellationToken cancellationToken)
         {
-            var result = await solution.TryRunCodeAnalysisRemoteAsync<ImmutableArray<SerializableSymbolAndProjectId>>(
+            var result = await solution.TryRunCodeAnalysisRemoteAsync<IList<SerializableSymbolAndProjectId>>(
                 RemoteFeatureOptions.SymbolFinderEnabled,
                 nameof(IRemoteSymbolFinder.FindSolutionSourceDeclarationsWithNormalQueryAsync),
                 new object[] { name, ignoreCase, criteria }, cancellationToken).ConfigureAwait(false);
 
-            if (result.IsDefault)
+            if (result == null)
             {
                 return (false, ImmutableArray<SymbolAndProjectId>.Empty);
             }
@@ -139,12 +140,12 @@ internal static partial class DeclarationFinder
                 return (false, ImmutableArray<SymbolAndProjectId>.Empty);
             }
 
-            var result = await project.Solution.TryRunCodeAnalysisRemoteAsync<ImmutableArray<SerializableSymbolAndProjectId>>(
+            var result = await project.Solution.TryRunCodeAnalysisRemoteAsync<IList<SerializableSymbolAndProjectId>>(
                 RemoteFeatureOptions.SymbolFinderEnabled,
                 nameof(IRemoteSymbolFinder.FindProjectSourceDeclarationsWithNormalQueryAsync),
                 new object[] { project.Id, name, ignoreCase, criteria }, cancellationToken).ConfigureAwait(false);
 
-            if (result.IsDefault)
+            if (result == null)
             {
                 return (false, ImmutableArray<SymbolAndProjectId>.Empty);
             }
@@ -163,12 +164,12 @@ internal static partial class DeclarationFinder
                 return (false, ImmutableArray<SymbolAndProjectId>.Empty);
             }
 
-            var result = await project.Solution.TryRunCodeAnalysisRemoteAsync<ImmutableArray<SerializableSymbolAndProjectId>>(
+            var result = await project.Solution.TryRunCodeAnalysisRemoteAsync<IList<SerializableSymbolAndProjectId>>(
                 RemoteFeatureOptions.SymbolFinderEnabled,
                 nameof(IRemoteSymbolFinder.FindProjectSourceDeclarationsWithPatternAsync),
                 new object[] { project.Id, pattern, criteria }, cancellationToken).ConfigureAwait(false);
 
-            if (result.IsDefault)
+            if (result == null)
             {
                 return (false, ImmutableArray<SymbolAndProjectId>.Empty);
             }
diff --git a/src/Workspaces/Core/Portable/FindSymbols/IRemoteSymbolFinder.cs b/src/Workspaces/Core/Portable/FindSymbols/IRemoteSymbolFinder.cs
index c676d62ab248e..464535c989abd 100644
--- a/src/Workspaces/Core/Portable/FindSymbols/IRemoteSymbolFinder.cs
+++ b/src/Workspaces/Core/Portable/FindSymbols/IRemoteSymbolFinder.cs
@@ -14,16 +14,16 @@ internal interface IRemoteSymbolFinder
         Task FindReferencesAsync(SerializableSymbolAndProjectId symbolAndProjectIdArg, DocumentId[] documentArgs, CancellationToken cancellationToken);
         Task FindLiteralReferencesAsync(object value, TypeCode typeCode, CancellationToken cancellationToken);
 
-        Task<IReadOnlyList<SerializableSymbolAndProjectId>> FindAllDeclarationsWithNormalQueryAsync(
+        Task<IList<SerializableSymbolAndProjectId>> FindAllDeclarationsWithNormalQueryAsync(
             ProjectId projectId, string name, SearchKind searchKind, SymbolFilter criteria, CancellationToken cancellationToken);
 
-        Task<IReadOnlyList<SerializableSymbolAndProjectId>> FindSolutionSourceDeclarationsWithNormalQueryAsync(
+        Task<IList<SerializableSymbolAndProjectId>> FindSolutionSourceDeclarationsWithNormalQueryAsync(
             string name, bool ignoreCase, SymbolFilter criteria, CancellationToken cancellationToken);
 
-        Task<IReadOnlyList<SerializableSymbolAndProjectId>> FindProjectSourceDeclarationsWithNormalQueryAsync(
+        Task<IList<SerializableSymbolAndProjectId>> FindProjectSourceDeclarationsWithNormalQueryAsync(
             ProjectId projectId, string name, bool ignoreCase, SymbolFilter criteria, CancellationToken cancellationToken);
 
-        Task<IReadOnlyList<SerializableSymbolAndProjectId>> FindProjectSourceDeclarationsWithPatternAsync(
+        Task<IList<SerializableSymbolAndProjectId>> FindProjectSourceDeclarationsWithPatternAsync(
             ProjectId projectId, string pattern, SymbolFilter criteria, CancellationToken cancellationToken);
     }
 }
diff --git a/src/Workspaces/Core/Portable/SymbolSearch/IRemoteSymbolSearchUpdateEngine.cs b/src/Workspaces/Core/Portable/SymbolSearch/IRemoteSymbolSearchUpdateEngine.cs
index f784a9b343622..6f7a0a047d91f 100644
--- a/src/Workspaces/Core/Portable/SymbolSearch/IRemoteSymbolSearchUpdateEngine.cs
+++ b/src/Workspaces/Core/Portable/SymbolSearch/IRemoteSymbolSearchUpdateEngine.cs
@@ -11,8 +11,8 @@ internal interface IRemoteSymbolSearchUpdateEngine
     {
         Task UpdateContinuouslyAsync(string sourceName, string localSettingsDirectory);
 
-        Task<IReadOnlyList<PackageWithTypeResult>> FindPackagesWithTypeAsync(string source, string name, int arity, CancellationToken cancellationToken);
-        Task<IReadOnlyList<PackageWithAssemblyResult>> FindPackagesWithAssemblyAsync(string source, string name, CancellationToken cancellationToken);
-        Task<IReadOnlyList<ReferenceAssemblyWithTypeResult>> FindReferenceAssembliesWithTypeAsync(string name, int arity, CancellationToken cancellationToken);
+        Task<IList<PackageWithTypeResult>> FindPackagesWithTypeAsync(string source, string name, int arity, CancellationToken cancellationToken);
+        Task<IList<PackageWithAssemblyResult>> FindPackagesWithAssemblyAsync(string source, string name, CancellationToken cancellationToken);
+        Task<IList<ReferenceAssemblyWithTypeResult>> FindReferenceAssembliesWithTypeAsync(string name, int arity, CancellationToken cancellationToken);
     }
 }
diff --git a/src/Workspaces/Core/Portable/SymbolSearch/ISymbolSearchService.cs b/src/Workspaces/Core/Portable/SymbolSearch/ISymbolSearchService.cs
index 9a7725e331f58..c38f1e982ee21 100644
--- a/src/Workspaces/Core/Portable/SymbolSearch/ISymbolSearchService.cs
+++ b/src/Workspaces/Core/Portable/SymbolSearch/ISymbolSearchService.cs
@@ -23,7 +23,7 @@ internal interface ISymbolSearchService : IWorkspaceService
         /// Implementations should return results in order from best to worst (from their
         /// perspective).
         /// </summary>
-        Task<IReadOnlyList<PackageWithTypeResult>> FindPackagesWithTypeAsync(
+        Task<IList<PackageWithTypeResult>> FindPackagesWithTypeAsync(
             string source, string name, int arity, CancellationToken cancellationToken);
 
         /// <summary>
@@ -34,7 +34,7 @@ internal interface ISymbolSearchService : IWorkspaceService
         /// Implementations should return results in order from best to worst (from their
         /// perspective).
         /// </summary>
-        Task<IReadOnlyList<PackageWithAssemblyResult>> FindPackagesWithAssemblyAsync(
+        Task<IList<PackageWithAssemblyResult>> FindPackagesWithAssemblyAsync(
             string source, string assemblyName, CancellationToken cancellationToken);
 
         /// <summary>
@@ -46,7 +46,7 @@ internal interface ISymbolSearchService : IWorkspaceService
         /// Implementations should return results in order from best to worst (from their
         /// perspective).
         /// </summary>
-        Task<IReadOnlyList<ReferenceAssemblyWithTypeResult>> FindReferenceAssembliesWithTypeAsync(
+        Task<IList<ReferenceAssemblyWithTypeResult>> FindReferenceAssembliesWithTypeAsync(
             string name, int arity, CancellationToken cancellationToken);
     }
 
@@ -64,7 +64,7 @@ protected PackageResult(string packageName, int rank)
 
     internal class PackageWithTypeResult : PackageResult
     {
-        public readonly IReadOnlyList<string> ContainingNamespaceNames;
+        public readonly IList<string> ContainingNamespaceNames;
         public readonly string TypeName;
         public readonly string Version;
 
@@ -73,7 +73,7 @@ internal class PackageWithTypeResult : PackageResult
             string typeName,
             string version,
             int rank,
-            IReadOnlyList<string> containingNamespaceNames)
+            IList<string> containingNamespaceNames)
             : base(packageName, rank)
         {
             TypeName = typeName;
@@ -118,14 +118,14 @@ public int CompareTo(PackageWithAssemblyResult other)
 
     internal class ReferenceAssemblyWithTypeResult
     {
-        public readonly IReadOnlyList<string> ContainingNamespaceNames;
+        public readonly IList<string> ContainingNamespaceNames;
         public readonly string AssemblyName;
         public readonly string TypeName;
 
         public ReferenceAssemblyWithTypeResult(
             string assemblyName,
             string typeName,
-            IReadOnlyList<string> containingNamespaceNames)
+            IList<string> containingNamespaceNames)
         {
             AssemblyName = assemblyName;
             TypeName = typeName;
@@ -136,22 +136,22 @@ internal class ReferenceAssemblyWithTypeResult
     [ExportWorkspaceService(typeof(ISymbolSearchService)), Shared]
     internal class DefaultSymbolSearchService : ISymbolSearchService
     {
-        public Task<IReadOnlyList<PackageWithTypeResult>> FindPackagesWithTypeAsync(
+        public Task<IList<PackageWithTypeResult>> FindPackagesWithTypeAsync(
             string source, string name, int arity, CancellationToken cancellationToken)
         {
-            return SpecializedTasks.EmptyReadOnlyList<PackageWithTypeResult>();
+            return SpecializedTasks.EmptyList<PackageWithTypeResult>();
         }
 
-        public Task<IReadOnlyList<PackageWithAssemblyResult>> FindPackagesWithAssemblyAsync(
+        public Task<IList<PackageWithAssemblyResult>> FindPackagesWithAssemblyAsync(
             string source, string assemblyName, CancellationToken cancellationToken)
         {
-            return SpecializedTasks.EmptyReadOnlyList<PackageWithAssemblyResult>();
+            return SpecializedTasks.EmptyList<PackageWithAssemblyResult>();
         }
 
-        public Task<IReadOnlyList<ReferenceAssemblyWithTypeResult>> FindReferenceAssembliesWithTypeAsync(
+        public Task<IList<ReferenceAssemblyWithTypeResult>> FindReferenceAssembliesWithTypeAsync(
             string name, int arity, CancellationToken cancellationToken)
         {
-            return SpecializedTasks.EmptyReadOnlyList<ReferenceAssemblyWithTypeResult>();
+            return SpecializedTasks.EmptyList<ReferenceAssemblyWithTypeResult>();
         }
     }
 }
diff --git a/src/Workspaces/Core/Portable/Utilities/IReadOnlyListExtensions.cs b/src/Workspaces/Core/Portable/Utilities/IReadOnlyListExtensions.cs
index 1a4698cc9b540..b15e7de4427d1 100644
--- a/src/Workspaces/Core/Portable/Utilities/IReadOnlyListExtensions.cs
+++ b/src/Workspaces/Core/Portable/Utilities/IReadOnlyListExtensions.cs
@@ -1,12 +1,38 @@
-using System.Collections.Generic;
+using System.Collections;
+using System.Collections.Generic;
 
 namespace Microsoft.CodeAnalysis.Utilities
 {
     internal static class IReadOnlyListExtensions
     {
+        public static IReadOnlyList<T> ToReadOnlyList<T>(this IList<T> list)
+        {
+            if (list is IReadOnlyList<T> readOnlyList)
+            {
+                return readOnlyList;
+            }
+
+            return new ReadOnlyList<T>(list);
+        }
+
         public static T Last<T>(this IReadOnlyList<T> list)
         {
             return list[list.Count - 1];
         }
+
+        private class ReadOnlyList<T> : IReadOnlyList<T>
+        {
+            private readonly IList<T> _list;
+
+            public ReadOnlyList(IList<T> list)
+            {
+                _list = list;
+            }
+
+            public T this[int index] => _list[index];
+            public int Count => _list.Count;
+            public IEnumerator<T> GetEnumerator() => _list.GetEnumerator();
+            IEnumerator IEnumerable.GetEnumerator() => _list.GetEnumerator();
+        }
     }
 }
diff --git a/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_AddImport.cs b/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_AddImport.cs
index 004088f8b1ecd..3c5bad5880633 100644
--- a/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_AddImport.cs
+++ b/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_AddImport.cs
@@ -14,9 +14,9 @@ namespace Microsoft.CodeAnalysis.Remote
 {
     internal partial class CodeAnalysisService : IRemoteAddImportFeatureService
     {
-        public async Task<IReadOnlyList<AddImportFixData>> GetFixesAsync(
+        public async Task<IList<AddImportFixData>> GetFixesAsync(
             DocumentId documentId, TextSpan span, string diagnosticId, bool placeSystemNamespaceFirst,
-            bool searchReferenceAssemblies, IReadOnlyList<PackageSource> packageSources, CancellationToken cancellationToken)
+            bool searchReferenceAssemblies, IList<PackageSource> packageSources, CancellationToken cancellationToken)
         {
             using (UserOperationBooster.Boost())
             {
@@ -55,28 +55,28 @@ public SymbolSearchService(CodeAnalysisService codeAnalysisService)
                 this.codeAnalysisService = codeAnalysisService;
             }
 
-            public async Task<IReadOnlyList<PackageWithTypeResult>> FindPackagesWithTypeAsync(
+            public async Task<IList<PackageWithTypeResult>> FindPackagesWithTypeAsync(
                 string source, string name, int arity, CancellationToken cancellationToken)
             {
-                var result = await codeAnalysisService.Rpc.InvokeAsync<IReadOnlyList<PackageWithTypeResult>>(
+                var result = await codeAnalysisService.Rpc.InvokeAsync<IList<PackageWithTypeResult>>(
                     nameof(FindPackagesWithTypeAsync), source, name, arity).ConfigureAwait(false);
 
                 return result;
             }
 
-            public async Task<IReadOnlyList<PackageWithAssemblyResult>> FindPackagesWithAssemblyAsync(
+            public async Task<IList<PackageWithAssemblyResult>> FindPackagesWithAssemblyAsync(
                 string source, string assemblyName, CancellationToken cancellationToken)
             {
-                var result = await codeAnalysisService.Rpc.InvokeAsync<IReadOnlyList<PackageWithAssemblyResult>>(
+                var result = await codeAnalysisService.Rpc.InvokeAsync<IList<PackageWithAssemblyResult>>(
                     nameof(FindPackagesWithAssemblyAsync), source, assemblyName).ConfigureAwait(false);
 
                 return result;
             }
 
-            public async Task<IReadOnlyList<ReferenceAssemblyWithTypeResult>> FindReferenceAssembliesWithTypeAsync(
+            public async Task<IList<ReferenceAssemblyWithTypeResult>> FindReferenceAssembliesWithTypeAsync(
                 string name, int arity, CancellationToken cancellationToken)
             {
-                var result = await codeAnalysisService.Rpc.InvokeAsync<IReadOnlyList<ReferenceAssemblyWithTypeResult>>(
+                var result = await codeAnalysisService.Rpc.InvokeAsync<IList<ReferenceAssemblyWithTypeResult>>(
                     nameof(FindReferenceAssembliesWithTypeAsync), name, arity).ConfigureAwait(false);
 
                 return result;
diff --git a/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_DesignerAttributes.cs b/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_DesignerAttributes.cs
index 8a49d29bd7f8a..3aefc8e2ea1c3 100644
--- a/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_DesignerAttributes.cs
+++ b/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_DesignerAttributes.cs
@@ -19,7 +19,7 @@ internal partial class CodeAnalysisService : IRemoteDesignerAttributeService
         /// 
         /// This will be called by ServiceHub/JsonRpc framework
         /// </summary>
-        public async Task<IReadOnlyList<DesignerAttributeDocumentData>> ScanDesignerAttributesAsync(ProjectId projectId, CancellationToken cancellationToken)
+        public async Task<IList<DesignerAttributeDocumentData>> ScanDesignerAttributesAsync(ProjectId projectId, CancellationToken cancellationToken)
         {
             using (RoslynLogger.LogBlock(FunctionId.CodeAnalysisService_GetDesignerAttributesAsync, projectId.DebugName, cancellationToken))
             {
@@ -31,7 +31,7 @@ public async Task<IReadOnlyList<DesignerAttributeDocumentData>> ScanDesignerAttr
 
                 if (data.Count == 0)
                 {
-                    return SpecializedCollections.EmptyReadOnlyList<DesignerAttributeDocumentData>();
+                    return SpecializedCollections.EmptyList<DesignerAttributeDocumentData>();
                 }
 
                 return data.Values.ToList();
diff --git a/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_DocumentHighlights.cs b/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_DocumentHighlights.cs
index e8af78b445657..db3147ec915fd 100644
--- a/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_DocumentHighlights.cs
+++ b/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_DocumentHighlights.cs
@@ -14,7 +14,7 @@ namespace Microsoft.CodeAnalysis.Remote
     // root level service for all Roslyn services
     internal partial class CodeAnalysisService : IRemoteDocumentHighlights
     {
-        public async Task<IReadOnlyList<SerializableDocumentHighlights>> GetDocumentHighlightsAsync(
+        public async Task<IList<SerializableDocumentHighlights>> GetDocumentHighlightsAsync(
             DocumentId documentId, int position, DocumentId[] documentIdsToSearch, CancellationToken cancellationToken)
         {
             // NOTE: In projection scenarios, we might get a set of documents to search
diff --git a/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_NavigateTo.cs b/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_NavigateTo.cs
index 346f1714b25d4..7ceff52363cec 100644
--- a/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_NavigateTo.cs
+++ b/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_NavigateTo.cs
@@ -10,7 +10,7 @@ namespace Microsoft.CodeAnalysis.Remote
 {
     internal partial class CodeAnalysisService : IRemoteNavigateToSearchService
     {
-        public async Task<IReadOnlyList<SerializableNavigateToSearchResult>> SearchDocumentAsync(
+        public async Task<IList<SerializableNavigateToSearchResult>> SearchDocumentAsync(
             DocumentId documentId, string searchPattern, CancellationToken cancellationToken)
         {
             using (UserOperationBooster.Boost())
@@ -25,7 +25,7 @@ internal partial class CodeAnalysisService : IRemoteNavigateToSearchService
             }
         }
 
-        public async Task<IReadOnlyList<SerializableNavigateToSearchResult>> SearchProjectAsync(
+        public async Task<IList<SerializableNavigateToSearchResult>> SearchProjectAsync(
             ProjectId projectId, string searchPattern, CancellationToken cancellationToken)
         {
             using (UserOperationBooster.Boost())
diff --git a/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_SymbolFinder.cs b/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_SymbolFinder.cs
index 588a34983121d..740060c72ea09 100644
--- a/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_SymbolFinder.cs
+++ b/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_SymbolFinder.cs
@@ -60,7 +60,7 @@ public async Task FindLiteralReferencesAsync(object value, TypeCode typeCode, Ca
             }
         }
 
-        public async Task<IReadOnlyList<SerializableSymbolAndProjectId>> FindAllDeclarationsWithNormalQueryAsync(
+        public async Task<IList<SerializableSymbolAndProjectId>> FindAllDeclarationsWithNormalQueryAsync(
             ProjectId projectId, string name, SearchKind searchKind, SymbolFilter criteria, CancellationToken cancellationToken)
         {
             using (UserOperationBooster.Boost())
@@ -78,7 +78,7 @@ public async Task FindLiteralReferencesAsync(object value, TypeCode typeCode, Ca
             }
         }
 
-        public async Task<IReadOnlyList<SerializableSymbolAndProjectId>> FindSolutionSourceDeclarationsWithNormalQueryAsync(
+        public async Task<IList<SerializableSymbolAndProjectId>> FindSolutionSourceDeclarationsWithNormalQueryAsync(
             string name, bool ignoreCase, SymbolFilter criteria, CancellationToken cancellationToken)
         {
             using (UserOperationBooster.Boost())
@@ -91,7 +91,7 @@ public async Task FindLiteralReferencesAsync(object value, TypeCode typeCode, Ca
             }
         }
 
-        public async Task<IReadOnlyList<SerializableSymbolAndProjectId>> FindProjectSourceDeclarationsWithNormalQueryAsync(
+        public async Task<IList<SerializableSymbolAndProjectId>> FindProjectSourceDeclarationsWithNormalQueryAsync(
             ProjectId projectId, string name, bool ignoreCase, SymbolFilter criteria, CancellationToken cancellationToken)
         {
             using (UserOperationBooster.Boost())
@@ -106,7 +106,7 @@ public async Task FindLiteralReferencesAsync(object value, TypeCode typeCode, Ca
             }
         }
 
-        public async Task<IReadOnlyList<SerializableSymbolAndProjectId>> FindProjectSourceDeclarationsWithPatternAsync(
+        public async Task<IList<SerializableSymbolAndProjectId>> FindProjectSourceDeclarationsWithPatternAsync(
             ProjectId projectId, string pattern, SymbolFilter criteria, CancellationToken cancellationToken)
         {
             using (UserOperationBooster.Boost())
diff --git a/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_TodoComments.cs b/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_TodoComments.cs
index ad4323e5a9261..4dec373eb2039 100644
--- a/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_TodoComments.cs
+++ b/src/Workspaces/Remote/ServiceHub/Services/CodeAnalysisService_TodoComments.cs
@@ -23,7 +23,7 @@ internal partial class CodeAnalysisService : IRemoteTodoCommentService
         /// 
         /// This will be called by ServiceHub/JsonRpc framework
         /// </summary>
-        public async Task<IReadOnlyList<TodoComment>> GetTodoCommentsAsync(PinnedSolutionInfo solutionInfo, DocumentId documentId, IReadOnlyList<TodoCommentDescriptor> tokens, CancellationToken cancellationToken)
+        public async Task<IList<TodoComment>> GetTodoCommentsAsync(PinnedSolutionInfo solutionInfo, DocumentId documentId, IList<TodoCommentDescriptor> tokens, CancellationToken cancellationToken)
         {
             using (RoslynLogger.LogBlock(FunctionId.CodeAnalysisService_GetTodoCommentsAsync, documentId.ProjectId.DebugName, cancellationToken))
             {
@@ -37,7 +37,7 @@ public async Task<IReadOnlyList<TodoComment>> GetTodoCommentsAsync(PinnedSolutio
                     return await service.GetTodoCommentsAsync(document, tokens, cancellationToken).ConfigureAwait(false);
                 }
 
-                return SpecializedCollections.EmptyReadOnlyList<TodoComment>();
+                return SpecializedCollections.EmptyList<TodoComment>();
             }
         }
     }
diff --git a/src/Workspaces/Remote/ServiceHub/Services/RemoteSymbolSearchUpdateEngine.cs b/src/Workspaces/Remote/ServiceHub/Services/RemoteSymbolSearchUpdateEngine.cs
index 9d94411133f07..d46a9e47c43d0 100644
--- a/src/Workspaces/Remote/ServiceHub/Services/RemoteSymbolSearchUpdateEngine.cs
+++ b/src/Workspaces/Remote/ServiceHub/Services/RemoteSymbolSearchUpdateEngine.cs
@@ -29,7 +29,7 @@ public Task UpdateContinuouslyAsync(string sourceName, string localSettingsDirec
             return _updateEngine.UpdateContinuouslyAsync(sourceName, localSettingsDirectory);
         }
 
-        public async Task<IReadOnlyList<PackageWithTypeResult>> FindPackagesWithTypeAsync(string source, string name, int arity, CancellationToken cancellationToken)
+        public async Task<IList<PackageWithTypeResult>> FindPackagesWithTypeAsync(string source, string name, int arity, CancellationToken cancellationToken)
         {
             var results = await _updateEngine.FindPackagesWithTypeAsync(
                 source, name, arity, cancellationToken).ConfigureAwait(false);
@@ -37,7 +37,7 @@ public async Task<IReadOnlyList<PackageWithTypeResult>> FindPackagesWithTypeAsyn
             return results;
         }
 
-        public async Task<IReadOnlyList<PackageWithAssemblyResult>> FindPackagesWithAssemblyAsync(string source, string assemblyName, CancellationToken cancellationToken)
+        public async Task<IList<PackageWithAssemblyResult>> FindPackagesWithAssemblyAsync(string source, string assemblyName, CancellationToken cancellationToken)
         {
             var results = await _updateEngine.FindPackagesWithAssemblyAsync(
                 source, assemblyName, cancellationToken).ConfigureAwait(false);
@@ -45,7 +45,7 @@ public async Task<IReadOnlyList<PackageWithAssemblyResult>> FindPackagesWithAsse
             return results;
         }
 
-        public async Task<IReadOnlyList<ReferenceAssemblyWithTypeResult>> FindReferenceAssembliesWithTypeAsync(string name, int arity, CancellationToken cancellationToken)
+        public async Task<IList<ReferenceAssemblyWithTypeResult>> FindReferenceAssembliesWithTypeAsync(string name, int arity, CancellationToken cancellationToken)
         {
             var results = await _updateEngine.FindReferenceAssembliesWithTypeAsync(
                 name, arity, cancellationToken).ConfigureAwait(false);

From 49c4cafc78db63b6c6cae0d49bb973d84e1873bd Mon Sep 17 00:00:00 2001
From: Heejae Chang <hechang@microsoft.com>
Date: Thu, 10 Aug 2017 15:29:03 -0700
Subject: [PATCH 36/77] keep SelectAsArray

---
 .../DocumentHighlighting/AbstractDocumentHighlightsService.cs   | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Features/Core/Portable/DocumentHighlighting/AbstractDocumentHighlightsService.cs b/src/Features/Core/Portable/DocumentHighlighting/AbstractDocumentHighlightsService.cs
index d8a5ad324e172..d7d3b5506f387 100644
--- a/src/Features/Core/Portable/DocumentHighlighting/AbstractDocumentHighlightsService.cs
+++ b/src/Features/Core/Portable/DocumentHighlighting/AbstractDocumentHighlightsService.cs
@@ -55,7 +55,7 @@ internal abstract partial class AbstractDocumentHighlightsService : IDocumentHig
                 return (succeeded: false, ImmutableArray<DocumentHighlights>.Empty);
             }
 
-            return (true, result.Select(h => h.Rehydrate(document.Project.Solution)).ToImmutableArray());
+            return (true, result.SelectAsArray(h => h.Rehydrate(document.Project.Solution)));
         }
 
         private async Task<ImmutableArray<DocumentHighlights>> GetDocumentHighlightsInCurrentProcessAsync(

From f630b3fb26af3d43cceb88aa8e3643d449e43d3c Mon Sep 17 00:00:00 2001
From: Ashley Hauck <ashauck@microsoft.com>
Date: Fri, 4 Aug 2017 12:43:32 -0700
Subject: [PATCH 37/77] Fix calling generic local function with dynamic

---
 .../Portable/Binder/Binder_Invocation.cs      | 28 ++++++++++
 .../OverloadResolution/OverloadResolution.cs  |  3 +-
 .../Portable/CSharpResources.Designer.cs      |  9 ++++
 .../CSharp/Portable/CSharpResources.resx      |  3 ++
 .../CSharp/Portable/Errors/ErrorCode.cs       |  1 +
 .../Emit/CodeGen/CodeGenLocalFunctionTests.cs | 45 ++++++++++++++++
 .../Semantic/Semantics/LocalFunctionTests.cs  | 51 +++++++++++++++++++
 7 files changed, 139 insertions(+), 1 deletion(-)

diff --git a/src/Compilers/CSharp/Portable/Binder/Binder_Invocation.cs b/src/Compilers/CSharp/Portable/Binder/Binder_Invocation.cs
index b2ee2024f606f..d57dc6373cea4 100644
--- a/src/Compilers/CSharp/Portable/Binder/Binder_Invocation.cs
+++ b/src/Compilers/CSharp/Portable/Binder/Binder_Invocation.cs
@@ -682,6 +682,34 @@ private static bool HasApplicableConditionalMethod(OverloadResolutionResult<Meth
                 }
             }
 
+            // If we call an unconstructed generic local function with a dynamic argument, we need to
+            // dynamically dispatch the call (as the function must be constructed at runtime).
+            // Check for the situation where a dynamic argument influences a type parameter,
+            // and disallow it.
+            if (boundMethodGroup.TypeArgumentsOpt.IsDefaultOrEmpty && localFunction.IsGenericMethod)
+            {
+                var originalLocalFunction = localFunction.OriginalDefinition;
+                for (int i = 0; i < args.Length; ++i)
+                {
+                    var argument = args[i];
+                    var parameter = originalLocalFunction.Parameters[methodResult.ParameterFromArgument(i)];
+                    if (argument.HasDynamicType() &&
+                        parameter.Type.ContainsTypeParameter(parameterContainer: originalLocalFunction))
+                    {
+                        Error(diagnostics,
+                            ErrorCode.ERR_DynamicLocalFunctionTypeParameter,
+                            syntax, parameter.Name, localFunction.Name);
+                        return BindDynamicInvocation(
+                            syntax,
+                            boundMethodGroup,
+                            resolution.AnalyzedArguments,
+                            resolution.OverloadResolutionResult.GetAllApplicableMembers(),
+                            diagnostics,
+                            queryClause);
+                    }
+                }
+            }
+
             return BindInvocationExpressionContinued(
                 node: syntax,
                 expression: expression,
diff --git a/src/Compilers/CSharp/Portable/Binder/Semantics/OverloadResolution/OverloadResolution.cs b/src/Compilers/CSharp/Portable/Binder/Semantics/OverloadResolution/OverloadResolution.cs
index a5a3121d29fc5..792e30ec2ff0e 100644
--- a/src/Compilers/CSharp/Portable/Binder/Semantics/OverloadResolution/OverloadResolution.cs
+++ b/src/Compilers/CSharp/Portable/Binder/Semantics/OverloadResolution/OverloadResolution.cs
@@ -2801,7 +2801,8 @@ private RefKind GetEffectiveParameterRefKind(ParameterSymbol parameter, RefKind
             EffectiveParameters effectiveParameters;
             if (member.Kind == SymbolKind.Method && (method = (MethodSymbol)(Symbol)member).Arity > 0)
             {
-                if (typeArgumentsBuilder.Count == 0 && arguments.HasDynamicArgument && !inferWithDynamic)
+                var isLocalFunction = ((MethodSymbol)(Symbol)member).MethodKind == MethodKind.LocalFunction;
+                if (typeArgumentsBuilder.Count == 0 && arguments.HasDynamicArgument && !inferWithDynamic && !isLocalFunction)
                 {
                     // Spec 7.5.4: Compile-time checking of dynamic overload resolution:
                     // * First, if F is a generic method and type arguments were provided, 
diff --git a/src/Compilers/CSharp/Portable/CSharpResources.Designer.cs b/src/Compilers/CSharp/Portable/CSharpResources.Designer.cs
index 6ce5d2dfd64c5..408c90d361ab0 100644
--- a/src/Compilers/CSharp/Portable/CSharpResources.Designer.cs
+++ b/src/Compilers/CSharp/Portable/CSharpResources.Designer.cs
@@ -3724,6 +3724,15 @@ internal class CSharpResources {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Cannot pass argument with dynamic type to generic parameter &apos;{0}&apos; of local function &apos;{1}&apos;..
+        /// </summary>
+        internal static string ERR_DynamicLocalFunctionTypeParameter {
+            get {
+                return ResourceManager.GetString("ERR_DynamicLocalFunctionTypeParameter", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to One or more types required to compile a dynamic expression cannot be found. Are you missing a reference?.
         /// </summary>
diff --git a/src/Compilers/CSharp/Portable/CSharpResources.resx b/src/Compilers/CSharp/Portable/CSharpResources.resx
index 34aca0f43aa2c..7132932beed43 100644
--- a/src/Compilers/CSharp/Portable/CSharpResources.resx
+++ b/src/Compilers/CSharp/Portable/CSharpResources.resx
@@ -5108,4 +5108,7 @@ To remove the warning, you can use /reference instead (set the Embed Interop Typ
   <data name="ERR_InvalidDebugInfo" xml:space="preserve">
     <value>Unable to read debug information of method '{0}' (token 0x{1:X8}) from assembly '{2}'</value>
   </data>
+  <data name="ERR_DynamicLocalFunctionTypeParameter" xml:space="preserve">
+    <value>Cannot pass argument with dynamic type to generic parameter '{0}' of local function '{1}'.</value>
+  </data>
 </root>
\ No newline at end of file
diff --git a/src/Compilers/CSharp/Portable/Errors/ErrorCode.cs b/src/Compilers/CSharp/Portable/Errors/ErrorCode.cs
index db7e38ebf5ef0..5275822f95b00 100644
--- a/src/Compilers/CSharp/Portable/Errors/ErrorCode.cs
+++ b/src/Compilers/CSharp/Portable/Errors/ErrorCode.cs
@@ -1496,6 +1496,7 @@ internal enum ErrorCode
         #region diagnostics introduced for C# 7.2
         ERR_FeatureNotAvailableInVersion7_2 = 8320,
         WRN_UnreferencedLocalFunction = 8321,
+        ERR_DynamicLocalFunctionTypeParameter = 8322,
         #endregion diagnostics introduced for C# 7.2
     }
 }
diff --git a/src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenLocalFunctionTests.cs b/src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenLocalFunctionTests.cs
index 8e36dd14c2848..e12c90834c960 100644
--- a/src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenLocalFunctionTests.cs
+++ b/src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenLocalFunctionTests.cs
@@ -3445,6 +3445,51 @@ Action<int> L5(int x)
 00222");
         }
 
+        [Fact]
+        [WorkItem(21317, "https://github.com/dotnet/roslyn/issues/21317")]
+        [CompilerTrait(CompilerFeature.Dynamic)]
+        public void DynamicGenericArg()
+        {
+            var src = @"
+void L1<T>(T x)
+{
+    Console.WriteLine(x);
+    Console.WriteLine(typeof(T).ToString());
+}
+dynamic val = 2;
+L1<object>(val);
+L1<int>(val);
+
+void L2<T>(int x, T y)
+{
+    Console.WriteLine(x);
+    Console.WriteLine(y);
+    Console.WriteLine(typeof(T).ToString());
+}
+L2(val, 3.0f);
+
+List<dynamic> listOfDynamic = new List<dynamic> { 1, 2, 3 };
+void L3<T>(List<T> x)
+{
+    Console.WriteLine(string.Join("", "", x));
+    Console.WriteLine(typeof(T).ToString());
+}
+L3(listOfDynamic);
+";
+            var output = @"
+2
+System.Object
+2
+System.Int32
+2
+3
+System.Single
+1, 2, 3
+System.Object
+";
+            VerifyOutputInMain(src, output, "System", "System.Collections.Generic");
+        }
+
         [Fact]
         [CompilerTrait(CompilerFeature.Dynamic, CompilerFeature.Params)]
         public void DynamicArgsAndParams()
diff --git a/src/Compilers/CSharp/Test/Semantic/Semantics/LocalFunctionTests.cs b/src/Compilers/CSharp/Test/Semantic/Semantics/LocalFunctionTests.cs
index a5a761ddf1dd3..9fff5e37142e4 100644
--- a/src/Compilers/CSharp/Test/Semantic/Semantics/LocalFunctionTests.cs
+++ b/src/Compilers/CSharp/Test/Semantic/Semantics/LocalFunctionTests.cs
@@ -3163,5 +3163,56 @@ async Task<dynamic> L<T>(Func<dynamic, T> t, object p)
                 //             => await L(async m => L(async d => await d, m), p);
                 Diagnostic(ErrorCode.WRN_AsyncLacksAwaits, "=>").WithLocation(8, 32));
         }
+
+        [Fact]
+        [WorkItem(21317, "https://github.com/dotnet/roslyn/issues/21317")]
+        [CompilerTrait(CompilerFeature.Dynamic)]
+        public void DynamicGenericArg()
+        {
+            var src = @"
+using System;
+using System.Collections.Generic;
+class C
+{
+    static void M()
+    {
+        dynamic val = 2;
+
+        void L1<T>(T x)
+        {
+            Console.Write(x);
+        }
+        L1(val);
+
+        void L2<T>(int x, T y)
+        {
+            Console.Write(x);
+        }
+        L2(1, val);
+
+        dynamic dynamicList = new List<int>();
+        void L3<T>(List<T> x)
+        {
+            Console.Write(x);
+        }
+        L3(dynamicList);
+    }
+}
+";
+            VerifyDiagnostics(src,
+                // (14,9): error CS8322: Cannot pass argument with dynamic type to generic parameter 'x' of local function 'L1'.
+                //         L1(val);
+                Diagnostic(ErrorCode.ERR_DynamicLocalFunctionTypeParameter, "L1(val)").WithArguments("x", "L1").WithLocation(14, 9),
+                // (20,9): error CS8322: Cannot pass argument with dynamic type to generic parameter 'y' of local function 'L2'.
+                //         L2(1, val);
+                Diagnostic(ErrorCode.ERR_DynamicLocalFunctionTypeParameter, "L2(1, val)").WithArguments("y", "L2").WithLocation(20, 9),
+                // (27,9): error CS0411: The type arguments for method 'L3<T>(List<T>)' cannot be inferred from the usage. Try specifying the type arguments explicitly.
+                //         L3(dynamicList);
+                Diagnostic(ErrorCode.ERR_CantInferMethTypeArgs, "L3").WithArguments("L3<T>(System.Collections.Generic.List<T>)").WithLocation(27, 9),
+                // (23,14): warning CS8321: The local function 'L3' is declared but never used
+                //         void L3<T>(List<T> x)
+                Diagnostic(ErrorCode.WRN_UnreferencedLocalFunction, "L3").WithArguments("L3").WithLocation(23, 14)
+                );
+        }
     }
 }

From d515479a9ce2494f81966b811ac0dc6647a33beb Mon Sep 17 00:00:00 2001
From: Fredric Silberberg <frsilb@microsoft.com>
Date: Fri, 11 Aug 2017 13:04:25 -0700
Subject: [PATCH 38/77] Rename ILockStatement.LockedObject to Expression.

---
 .../Operations/CSharpOperationFactory.cs         |  4 ++--
 .../Generated/Operations.xml.Generated.cs        | 16 ++++++++--------
 .../Core/Portable/Operations/ILockStatement.cs   |  4 ++--
 .../Core/Portable/Operations/OperationCloner.cs  |  2 +-
 .../Core/Portable/PublicAPI.Unshipped.txt        |  2 +-
 .../Operations/VisualBasicOperationFactory.vb    |  4 ++--
 .../Compilation/OperationTreeVerifier.cs         |  2 +-
 7 files changed, 17 insertions(+), 17 deletions(-)

diff --git a/src/Compilers/CSharp/Portable/Operations/CSharpOperationFactory.cs b/src/Compilers/CSharp/Portable/Operations/CSharpOperationFactory.cs
index bd1721ce525c0..18bd7ab0484cf 100644
--- a/src/Compilers/CSharp/Portable/Operations/CSharpOperationFactory.cs
+++ b/src/Compilers/CSharp/Portable/Operations/CSharpOperationFactory.cs
@@ -1219,12 +1219,12 @@ private IReturnStatement CreateBoundYieldReturnStatementOperation(BoundYieldRetu
 
         private ILockStatement CreateBoundLockStatementOperation(BoundLockStatement boundLockStatement)
         {
-            Lazy<IOperation> lockedObject = new Lazy<IOperation>(() => Create(boundLockStatement.Argument));
+            Lazy<IOperation> expression = new Lazy<IOperation>(() => Create(boundLockStatement.Argument));
             Lazy<IOperation> body = new Lazy<IOperation>(() => Create(boundLockStatement.Body));
             SyntaxNode syntax = boundLockStatement.Syntax;
             ITypeSymbol type = null;
             Optional<object> constantValue = default(Optional<object>);
-            return new LazyLockStatement(lockedObject, body, _semanticModel, syntax, type, constantValue);
+            return new LazyLockStatement(expression, body, _semanticModel, syntax, type, constantValue);
         }
 
         private IInvalidStatement CreateBoundBadStatementOperation(BoundBadStatement boundBadStatement)
diff --git a/src/Compilers/Core/Portable/Generated/Operations.xml.Generated.cs b/src/Compilers/Core/Portable/Generated/Operations.xml.Generated.cs
index 2db8a93319f5b..e7c90f46bb3e6 100644
--- a/src/Compilers/Core/Portable/Generated/Operations.xml.Generated.cs
+++ b/src/Compilers/Core/Portable/Generated/Operations.xml.Generated.cs
@@ -2861,20 +2861,20 @@ internal abstract partial class BaseLockStatement : Operation, ILockStatement
         {
         }
 
-        protected abstract IOperation LockedObjectImpl { get; }
+        protected abstract IOperation ExpressionImpl { get; }
         protected abstract IOperation BodyImpl { get; }
         public override IEnumerable<IOperation> Children
         {
             get
             {
-                yield return LockedObject;
+                yield return Expression;
                 yield return Body;
             }
         }
         /// <summary>
-        /// Value to be locked.
+        /// Expression producing a value to be locked.
         /// </summary>
-        public IOperation LockedObject => Operation.SetParentOperation(LockedObjectImpl, this);
+        public IOperation Expression => Operation.SetParentOperation(ExpressionImpl, this);
         /// <summary>
         /// Body of the lock, to be executed while holding the lock.
         /// </summary>
@@ -2894,14 +2894,14 @@ public override void Accept(OperationVisitor visitor)
     /// </summary>
     internal sealed partial class LockStatement : BaseLockStatement, ILockStatement
     {
-        public LockStatement(IOperation lockedObject, IOperation body, SemanticModel semanticModel, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) :
+        public LockStatement(IOperation expression, IOperation body, SemanticModel semanticModel, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) :
             base(semanticModel, syntax, type, constantValue)
         {
-            LockedObjectImpl = lockedObject;
+            ExpressionImpl = expression;
             BodyImpl = body;
         }
 
-        protected override IOperation LockedObjectImpl { get; }
+        protected override IOperation ExpressionImpl { get; }
         protected override IOperation BodyImpl { get; }
     }
 
@@ -2919,7 +2919,7 @@ public LazyLockStatement(Lazy<IOperation> lockedObject, Lazy<IOperation> body, S
             _lazyBody = body ?? throw new System.ArgumentNullException(nameof(body));
         }
 
-        protected override IOperation LockedObjectImpl => _lazyLockedObject.Value;
+        protected override IOperation ExpressionImpl => _lazyLockedObject.Value;
 
         protected override IOperation BodyImpl => _lazyBody.Value;
     }
diff --git a/src/Compilers/Core/Portable/Operations/ILockStatement.cs b/src/Compilers/Core/Portable/Operations/ILockStatement.cs
index 7d1c893782837..d433f2c709af5 100644
--- a/src/Compilers/Core/Portable/Operations/ILockStatement.cs
+++ b/src/Compilers/Core/Portable/Operations/ILockStatement.cs
@@ -14,9 +14,9 @@ namespace Microsoft.CodeAnalysis.Semantics
     public interface ILockStatement : IOperation
     {
         /// <summary>
-        /// Value to be locked.
+        /// Expression producing a value to be locked.
         /// </summary>
-        IOperation LockedObject { get; }
+        IOperation Expression { get; }
         /// <summary>
         /// Body of the lock, to be executed while holding the lock.
         /// </summary>
diff --git a/src/Compilers/Core/Portable/Operations/OperationCloner.cs b/src/Compilers/Core/Portable/Operations/OperationCloner.cs
index 038de6c65fd1c..b7ea9b804b7ae 100644
--- a/src/Compilers/Core/Portable/Operations/OperationCloner.cs
+++ b/src/Compilers/Core/Portable/Operations/OperationCloner.cs
@@ -131,7 +131,7 @@ public override IOperation VisitReturnStatement(IReturnStatement operation, obje
 
         public override IOperation VisitLockStatement(ILockStatement operation, object argument)
         {
-            return new LockStatement(Visit(operation.LockedObject), Visit(operation.Body), ((Operation)operation).SemanticModel, operation.Syntax, operation.Type, operation.ConstantValue);
+            return new LockStatement(Visit(operation.Expression), Visit(operation.Body), ((Operation)operation).SemanticModel, operation.Syntax, operation.Type, operation.ConstantValue);
         }
 
         public override IOperation VisitTryStatement(ITryStatement operation, object argument)
diff --git a/src/Compilers/Core/Portable/PublicAPI.Unshipped.txt b/src/Compilers/Core/Portable/PublicAPI.Unshipped.txt
index a9d2055d6d0f1..0ee0bfb67085f 100644
--- a/src/Compilers/Core/Portable/PublicAPI.Unshipped.txt
+++ b/src/Compilers/Core/Portable/PublicAPI.Unshipped.txt
@@ -497,7 +497,7 @@ Microsoft.CodeAnalysis.Semantics.ILocalReferenceExpression
 Microsoft.CodeAnalysis.Semantics.ILocalReferenceExpression.Local.get -> Microsoft.CodeAnalysis.ILocalSymbol
 Microsoft.CodeAnalysis.Semantics.ILockStatement
 Microsoft.CodeAnalysis.Semantics.ILockStatement.Body.get -> Microsoft.CodeAnalysis.IOperation
-Microsoft.CodeAnalysis.Semantics.ILockStatement.LockedObject.get -> Microsoft.CodeAnalysis.IOperation
+Microsoft.CodeAnalysis.Semantics.ILockStatement.Expression.get -> Microsoft.CodeAnalysis.IOperation
 Microsoft.CodeAnalysis.Semantics.ILoopStatement
 Microsoft.CodeAnalysis.Semantics.ILoopStatement.Body.get -> Microsoft.CodeAnalysis.IOperation
 Microsoft.CodeAnalysis.Semantics.ILoopStatement.LoopKind.get -> Microsoft.CodeAnalysis.Semantics.LoopKind
diff --git a/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb b/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
index 8eed84d14b050..3bb0e669bc218 100644
--- a/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
+++ b/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
@@ -1036,12 +1036,12 @@ Namespace Microsoft.CodeAnalysis.Semantics
         End Function
 
         Private Function CreateBoundSyncLockStatementOperation(boundSyncLockStatement As BoundSyncLockStatement) As ILockStatement
-            Dim lockedObject As Lazy(Of IOperation) = New Lazy(Of IOperation)(Function() Create(boundSyncLockStatement.LockExpression))
+            Dim expression As Lazy(Of IOperation) = New Lazy(Of IOperation)(Function() Create(boundSyncLockStatement.LockExpression))
             Dim body As Lazy(Of IOperation) = New Lazy(Of IOperation)(Function() Create(boundSyncLockStatement.Body))
             Dim syntax As SyntaxNode = boundSyncLockStatement.Syntax
             Dim type As ITypeSymbol = Nothing
             Dim constantValue As [Optional](Of Object) = New [Optional](Of Object)()
-            Return New LazyLockStatement(lockedObject, body, _semanticModel, syntax, type, constantValue)
+            Return New LazyLockStatement(expression, body, _semanticModel, syntax, type, constantValue)
         End Function
 
         Private Function CreateBoundNoOpStatementOperation(boundNoOpStatement As BoundNoOpStatement) As IEmptyStatement
diff --git a/src/Test/Utilities/Portable/Compilation/OperationTreeVerifier.cs b/src/Test/Utilities/Portable/Compilation/OperationTreeVerifier.cs
index 25ba77ef569b7..78701d2cad640 100644
--- a/src/Test/Utilities/Portable/Compilation/OperationTreeVerifier.cs
+++ b/src/Test/Utilities/Portable/Compilation/OperationTreeVerifier.cs
@@ -531,7 +531,7 @@ public override void VisitLockStatement(ILockStatement operation)
             LogString(nameof(ILockStatement));
             LogCommonPropertiesAndNewLine(operation);
 
-            Visit(operation.LockedObject, "LockedObject");
+            Visit(operation.Expression, "Expression");
             Visit(operation.Body, "Body");
         }
 

From 4203970ac28e20a38dbfedd4fc1d02d7d200cd43 Mon Sep 17 00:00:00 2001
From: Ashley Hauck <ashauck@microsoft.com>
Date: Fri, 11 Aug 2017 13:36:25 -0700
Subject: [PATCH 39/77] Disallow any inferred locfuncs with dynamic args

---
 .../Portable/Binder/Binder_Invocation.cs      |  42 +++----
 .../OverloadResolution/OverloadResolution.cs  |   3 +-
 .../Portable/CSharpResources.Designer.cs      |   2 +-
 .../CSharp/Portable/CSharpResources.resx      |   2 +-
 .../Emit/CodeGen/CodeGenLocalFunctionTests.cs | 116 ++++++++++++++----
 .../Semantic/Semantics/LocalFunctionTests.cs  |  57 +++++----
 6 files changed, 148 insertions(+), 74 deletions(-)

diff --git a/src/Compilers/CSharp/Portable/Binder/Binder_Invocation.cs b/src/Compilers/CSharp/Portable/Binder/Binder_Invocation.cs
index d57dc6373cea4..4489ab8a78346 100644
--- a/src/Compilers/CSharp/Portable/Binder/Binder_Invocation.cs
+++ b/src/Compilers/CSharp/Portable/Binder/Binder_Invocation.cs
@@ -682,32 +682,26 @@ private static bool HasApplicableConditionalMethod(OverloadResolutionResult<Meth
                 }
             }
 
-            // If we call an unconstructed generic local function with a dynamic argument, we need to
-            // dynamically dispatch the call (as the function must be constructed at runtime).
-            // Check for the situation where a dynamic argument influences a type parameter,
-            // and disallow it.
+            // If we call an unconstructed generic local function with a dynamic argument in
+            // a place where it influences the type parameters, we need to dynamically dispatch the call
+            // (as the function must be constructed at runtime). We cannot do that, so disallow that.
+            // However, doing a specific analysis of each argument and its corresponding parameter
+            // to check if it's generic (and allow dynamic in non-generic parameters) may break
+            // overload resolution in the future, if we ever allow overloaded local functions.
+            // So, just disallow any mixing of dynamic and inferred generics.
+            // (Explicitly-provided generic arguments are fine)
             if (boundMethodGroup.TypeArgumentsOpt.IsDefaultOrEmpty && localFunction.IsGenericMethod)
             {
-                var originalLocalFunction = localFunction.OriginalDefinition;
-                for (int i = 0; i < args.Length; ++i)
-                {
-                    var argument = args[i];
-                    var parameter = originalLocalFunction.Parameters[methodResult.ParameterFromArgument(i)];
-                    if (argument.HasDynamicType() &&
-                        parameter.Type.ContainsTypeParameter(parameterContainer: originalLocalFunction))
-                    {
-                        Error(diagnostics,
-                            ErrorCode.ERR_DynamicLocalFunctionTypeParameter,
-                            syntax, parameter.Name, localFunction.Name);
-                        return BindDynamicInvocation(
-                            syntax,
-                            boundMethodGroup,
-                            resolution.AnalyzedArguments,
-                            resolution.OverloadResolutionResult.GetAllApplicableMembers(),
-                            diagnostics,
-                            queryClause);
-                    }
-                }
+                Error(diagnostics,
+                    ErrorCode.ERR_DynamicLocalFunctionTypeParameter,
+                    syntax, localFunction.Name);
+                return BindDynamicInvocation(
+                    syntax,
+                    boundMethodGroup,
+                    resolution.AnalyzedArguments,
+                    resolution.OverloadResolutionResult.GetAllApplicableMembers(),
+                    diagnostics,
+                    queryClause);
             }
 
             return BindInvocationExpressionContinued(
diff --git a/src/Compilers/CSharp/Portable/Binder/Semantics/OverloadResolution/OverloadResolution.cs b/src/Compilers/CSharp/Portable/Binder/Semantics/OverloadResolution/OverloadResolution.cs
index 792e30ec2ff0e..a5a3121d29fc5 100644
--- a/src/Compilers/CSharp/Portable/Binder/Semantics/OverloadResolution/OverloadResolution.cs
+++ b/src/Compilers/CSharp/Portable/Binder/Semantics/OverloadResolution/OverloadResolution.cs
@@ -2801,8 +2801,7 @@ private RefKind GetEffectiveParameterRefKind(ParameterSymbol parameter, RefKind
             EffectiveParameters effectiveParameters;
             if (member.Kind == SymbolKind.Method && (method = (MethodSymbol)(Symbol)member).Arity > 0)
             {
-                var isLocalFunction = ((MethodSymbol)(Symbol)member).MethodKind == MethodKind.LocalFunction;
-                if (typeArgumentsBuilder.Count == 0 && arguments.HasDynamicArgument && !inferWithDynamic && !isLocalFunction)
+                if (typeArgumentsBuilder.Count == 0 && arguments.HasDynamicArgument && !inferWithDynamic)
                 {
                     // Spec 7.5.4: Compile-time checking of dynamic overload resolution:
                     // * First, if F is a generic method and type arguments were provided, 
diff --git a/src/Compilers/CSharp/Portable/CSharpResources.Designer.cs b/src/Compilers/CSharp/Portable/CSharpResources.Designer.cs
index 408c90d361ab0..47edeb0810dd8 100644
--- a/src/Compilers/CSharp/Portable/CSharpResources.Designer.cs
+++ b/src/Compilers/CSharp/Portable/CSharpResources.Designer.cs
@@ -3725,7 +3725,7 @@ internal class CSharpResources {
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to Cannot pass argument with dynamic type to generic parameter &apos;{0}&apos; of local function &apos;{1}&apos;..
+        ///   Looks up a localized string similar to Cannot pass argument with dynamic type to generic local function &apos;{0}&apos;. Try specifying the type arguments explicitly..
         /// </summary>
         internal static string ERR_DynamicLocalFunctionTypeParameter {
             get {
diff --git a/src/Compilers/CSharp/Portable/CSharpResources.resx b/src/Compilers/CSharp/Portable/CSharpResources.resx
index 7132932beed43..2023491b3a815 100644
--- a/src/Compilers/CSharp/Portable/CSharpResources.resx
+++ b/src/Compilers/CSharp/Portable/CSharpResources.resx
@@ -5109,6 +5109,6 @@ To remove the warning, you can use /reference instead (set the Embed Interop Typ
     <value>Unable to read debug information of method '{0}' (token 0x{1:X8}) from assembly '{2}'</value>
   </data>
   <data name="ERR_DynamicLocalFunctionTypeParameter" xml:space="preserve">
-    <value>Cannot pass argument with dynamic type to generic parameter '{0}' of local function '{1}'.</value>
+    <value>Cannot pass argument with dynamic type to generic local function '{0}'. Try specifying the type arguments explicitly.</value>
   </data>
 </root>
\ No newline at end of file
diff --git a/src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenLocalFunctionTests.cs b/src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenLocalFunctionTests.cs
index e12c90834c960..a750713147d1c 100644
--- a/src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenLocalFunctionTests.cs
+++ b/src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenLocalFunctionTests.cs
@@ -3453,43 +3453,113 @@ public void DynamicGenericArg()
             var src = @"
 void L1<T>(T x)
 {
-    Console.WriteLine(x);
-    Console.WriteLine(typeof(T).ToString());
+    Console.WriteLine($""{x}: {typeof(T)}"");
 }
 dynamic val = 2;
 L1<object>(val);
 L1<int>(val);
+L1<dynamic>(val);
+L1<dynamic>(4);
 
-void L2<T>(int x, T y)
-{
-    Console.WriteLine(x);
-    Console.WriteLine(y);
-    Console.WriteLine(typeof(T).ToString());
-}
-L2(val, 3.0f);
+void L2<T>(int x, T y) => Console.WriteLine($""{x}, {y}: {typeof(T)}"");
+L2<double>(val, 3.0f);
 
 List<dynamic> listOfDynamic = new List<dynamic> { 1, 2, 3 };
-void L3<T>(List<T> x)
-{
-    Console.WriteLine(string.Join("", "", x));
-    Console.WriteLine(typeof(T).ToString());
-}
+void L3<T>(List<T> x) => Console.WriteLine($""{string.Join("", "", x)}: {typeof(T)}"");
 L3(listOfDynamic);
+
+void L4<T>(T x, params int[] y) => Console.WriteLine($""{x}, {string.Join("", "", y)}: {typeof(T)}"");
+L4<dynamic>(val, 3, 4);
+L4<int>(val, 3, 4);
+L4<int>(1, 3, val);
+
+void L5<T>(int x, params T[] y) => Console.WriteLine($""{x}, {string.Join("", "", y)}: {typeof(T)}"");
+L5<int>(val, 3, 4);
+L5<int>(1, 3, val);
+L5<dynamic>(1, 3, val);
 ";
             var output = @"
-2
-System.Object
-2
-System.Int32
-2
-3
-System.Single
-1, 2, 3
-System.Object
+2: System.Object
+2: System.Int32
+2: System.Object
+4: System.Object
+2, 3: System.Single
+1, 2, 3: System.Object
+2, 3, 4: System.Object
+2, 3, 4: System.Int32
+1, 3, 2: System.Int32
+2, 3, 4: System.Int32
+1, 3, 2: System.Int32
+1, 3, 2: System.Object
 ";
             VerifyOutputInMain(src, output, "System", "System.Collections.Generic");
         }
 
+        [Fact]
+        [WorkItem(21317, "https://github.com/dotnet/roslyn/issues/21317")]
+        [CompilerTrait(CompilerFeature.Dynamic)]
+        public void DynamicGenericClassMethod()
+        {
+            var src = @"
+using System;
+class C1<T1>
+{
+    public static void M1<T2>()
+    {
+        void F(int x)
+        {
+            Console.WriteLine($""C1<{typeof(T1)}>.M1<{typeof(T2)}>.F({x})"");
+        }
+        F((dynamic)2);
+    }
+    public static void M2()
+    {
+        void F(int x)
+        {
+            Console.WriteLine($""C1<{typeof(T1)}>.M2.F({x})"");
+        }
+        F((dynamic)2);
+    }
+}
+class C2
+{
+    public static void M1<T2>()
+    {
+        void F(int x)
+        {
+            Console.WriteLine($""C2.M1<{typeof(T2)}>.F({x})"");
+        }
+        F((dynamic)2);
+    }
+    public static void M2()
+    {
+        void F(int x)
+        {
+            Console.WriteLine($""C2.M2.F({x})"");
+        }
+        F((dynamic)2);
+    }
+}
+class Program
+{
+    static void Main()
+    {
+        C1<int>.M1<float>();
+        C1<int>.M2();
+        C2.M1<float>();
+        C2.M2();
+    }
+}
+";
+            var output = @"
+C1<System.Int32>.M1<System.Single>.F(2)
+C1<System.Int32>.M2.F(2)
+C2.M1<System.Single>.F(2)
+C2.M2.F(2)
+";
+            VerifyOutput(src, output);
+        }
+
         [Fact]
         [CompilerTrait(CompilerFeature.Dynamic, CompilerFeature.Params)]
         public void DynamicArgsAndParams()
diff --git a/src/Compilers/CSharp/Test/Semantic/Semantics/LocalFunctionTests.cs b/src/Compilers/CSharp/Test/Semantic/Semantics/LocalFunctionTests.cs
index 9fff5e37142e4..953efa4677a9b 100644
--- a/src/Compilers/CSharp/Test/Semantic/Semantics/LocalFunctionTests.cs
+++ b/src/Compilers/CSharp/Test/Semantic/Semantics/LocalFunctionTests.cs
@@ -3170,48 +3170,59 @@ async Task<dynamic> L<T>(Func<dynamic, T> t, object p)
         public void DynamicGenericArg()
         {
             var src = @"
-using System;
 using System.Collections.Generic;
 class C
 {
     static void M()
     {
         dynamic val = 2;
+        dynamic dynamicList = new List<int>();
 
-        void L1<T>(T x)
-        {
-            Console.Write(x);
-        }
+        void L1<T>(T x) { }
         L1(val);
 
-        void L2<T>(int x, T y)
-        {
-            Console.Write(x);
-        }
+        void L2<T>(int x, T y) { }
         L2(1, val);
+        L2(val, 3.0f);
 
-        dynamic dynamicList = new List<int>();
-        void L3<T>(List<T> x)
-        {
-            Console.Write(x);
-        }
+        void L3<T>(List<T> x) { }
         L3(dynamicList);
+
+        void L4<T>(int x, params T[] y) { }
+        L4(1, 2, val);
+        L4(val, 3, 4);
+
+        void L5<T>(T x, params int[] y) { }
+        L5(val, 1, 2);
+        L5(1, 3, val);
     }
 }
 ";
             VerifyDiagnostics(src,
-                // (14,9): error CS8322: Cannot pass argument with dynamic type to generic parameter 'x' of local function 'L1'.
+                // (11,9): error CS8322: Cannot pass argument with dynamic type to generic local function 'L1'. Try specifying the type arguments explicitly.
                 //         L1(val);
-                Diagnostic(ErrorCode.ERR_DynamicLocalFunctionTypeParameter, "L1(val)").WithArguments("x", "L1").WithLocation(14, 9),
-                // (20,9): error CS8322: Cannot pass argument with dynamic type to generic parameter 'y' of local function 'L2'.
+                Diagnostic(ErrorCode.ERR_DynamicLocalFunctionTypeParameter, "L1(val)").WithArguments("L1").WithLocation(11, 9),
+                // (14,9): error CS8322: Cannot pass argument with dynamic type to generic local function 'L2'. Try specifying the type arguments explicitly.
                 //         L2(1, val);
-                Diagnostic(ErrorCode.ERR_DynamicLocalFunctionTypeParameter, "L2(1, val)").WithArguments("y", "L2").WithLocation(20, 9),
-                // (27,9): error CS0411: The type arguments for method 'L3<T>(List<T>)' cannot be inferred from the usage. Try specifying the type arguments explicitly.
+                Diagnostic(ErrorCode.ERR_DynamicLocalFunctionTypeParameter, "L2(1, val)").WithArguments("L2").WithLocation(14, 9),
+                // (15,9): error CS8322: Cannot pass argument with dynamic type to generic local function 'L2'. Try specifying the type arguments explicitly.
+                //         L2(val, 3.0f);
+                Diagnostic(ErrorCode.ERR_DynamicLocalFunctionTypeParameter, "L2(val, 3.0f)").WithArguments("L2").WithLocation(15, 9),
+                // (18,9): error CS8322: Cannot pass argument with dynamic type to generic local function 'L3'. Try specifying the type arguments explicitly.
                 //         L3(dynamicList);
-                Diagnostic(ErrorCode.ERR_CantInferMethTypeArgs, "L3").WithArguments("L3<T>(System.Collections.Generic.List<T>)").WithLocation(27, 9),
-                // (23,14): warning CS8321: The local function 'L3' is declared but never used
-                //         void L3<T>(List<T> x)
-                Diagnostic(ErrorCode.WRN_UnreferencedLocalFunction, "L3").WithArguments("L3").WithLocation(23, 14)
+                Diagnostic(ErrorCode.ERR_DynamicLocalFunctionTypeParameter, "L3(dynamicList)").WithArguments("L3").WithLocation(18, 9),
+                // (21,9): error CS8322: Cannot pass argument with dynamic type to generic local function 'L4'. Try specifying the type arguments explicitly.
+                //         L4(1, 2, val);
+                Diagnostic(ErrorCode.ERR_DynamicLocalFunctionTypeParameter, "L4(1, 2, val)").WithArguments("L4").WithLocation(21, 9),
+                // (22,9): error CS8322: Cannot pass argument with dynamic type to generic local function 'L4'. Try specifying the type arguments explicitly.
+                //         L4(val, 3, 4);
+                Diagnostic(ErrorCode.ERR_DynamicLocalFunctionTypeParameter, "L4(val, 3, 4)").WithArguments("L4").WithLocation(22, 9),
+                // (25,9): error CS8322: Cannot pass argument with dynamic type to generic local function 'L5'. Try specifying the type arguments explicitly.
+                //         L5(val, 1, 2);
+                Diagnostic(ErrorCode.ERR_DynamicLocalFunctionTypeParameter, "L5(val, 1, 2)").WithArguments("L5").WithLocation(25, 9),
+                // (26,9): error CS8322: Cannot pass argument with dynamic type to generic local function 'L5'. Try specifying the type arguments explicitly.
+                //         L5(1, 3, val);
+                Diagnostic(ErrorCode.ERR_DynamicLocalFunctionTypeParameter, "L5(1, 3, val)").WithArguments("L5").WithLocation(26, 9)
                 );
         }
     }

From 68bb9579232f74b775c1e9516b129ceeeb7df455 Mon Sep 17 00:00:00 2001
From: Fredric Silberberg <frsilb@microsoft.com>
Date: Fri, 11 Aug 2017 14:01:46 -0700
Subject: [PATCH 40/77] Refactors INullCoalescingExpression to ICoalesce
 expression, and properties to sensible names.

---
 .../Operations/CSharpOperationFactory.cs      |  8 +--
 .../IOperationTests_IConversionExpression.cs  |  8 +--
 .../Generated/Operations.xml.Generated.cs     | 52 +++++++++----------
 ...ngExpression.cs => ICoalesceExpression.cs} |  8 +--
 .../Portable/Operations/OperationCloner.cs    |  4 +-
 .../Core/Portable/Operations/OperationKind.cs |  4 +-
 .../Portable/Operations/OperationVisitor.cs   |  4 +-
 .../Core/Portable/PublicAPI.Unshipped.txt     | 12 ++---
 .../Operations/VisualBasicOperationFactory.vb |  8 +--
 ...ddParameterCheckCodeRefactoringProvider.cs |  6 +--
 ...erCodeRefactoringProviderMemberCreation.cs |  4 +-
 .../Compilation/OperationTreeVerifier.cs      |  8 +--
 .../Compilation/TestOperationWalker.cs        |  4 +-
 13 files changed, 65 insertions(+), 65 deletions(-)
 rename src/Compilers/Core/Portable/Operations/{INullCoalescingExpression.cs => ICoalesceExpression.cs} (75%)

diff --git a/src/Compilers/CSharp/Portable/Operations/CSharpOperationFactory.cs b/src/Compilers/CSharp/Portable/Operations/CSharpOperationFactory.cs
index bd1721ce525c0..208325726c44d 100644
--- a/src/Compilers/CSharp/Portable/Operations/CSharpOperationFactory.cs
+++ b/src/Compilers/CSharp/Portable/Operations/CSharpOperationFactory.cs
@@ -869,14 +869,14 @@ private IConditionalChoiceExpression CreateBoundConditionalOperatorOperation(Bou
             return new LazyConditionalChoiceExpression(condition, ifTrueValue, ifFalseValue, _semanticModel, syntax, type, constantValue);
         }
 
-        private INullCoalescingExpression CreateBoundNullCoalescingOperatorOperation(BoundNullCoalescingOperator boundNullCoalescingOperator)
+        private ICoalesceExpression CreateBoundNullCoalescingOperatorOperation(BoundNullCoalescingOperator boundNullCoalescingOperator)
         {
-            Lazy<IOperation> primaryOperand = new Lazy<IOperation>(() => Create(boundNullCoalescingOperator.LeftOperand));
-            Lazy<IOperation> secondaryOperand = new Lazy<IOperation>(() => Create(boundNullCoalescingOperator.RightOperand));
+            Lazy<IOperation> expression = new Lazy<IOperation>(() => Create(boundNullCoalescingOperator.LeftOperand));
+            Lazy<IOperation> whenNull = new Lazy<IOperation>(() => Create(boundNullCoalescingOperator.RightOperand));
             SyntaxNode syntax = boundNullCoalescingOperator.Syntax;
             ITypeSymbol type = boundNullCoalescingOperator.Type;
             Optional<object> constantValue = ConvertToOptional(boundNullCoalescingOperator.ConstantValue);
-            return new LazyNullCoalescingExpression(primaryOperand, secondaryOperand, _semanticModel, syntax, type, constantValue);
+            return new LazyCoalesceExpression(expression, whenNull, _semanticModel, syntax, type, constantValue);
         }
 
         private IAwaitExpression CreateBoundAwaitExpressionOperation(BoundAwaitExpression boundAwaitExpression)
diff --git a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IConversionExpression.cs b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IConversionExpression.cs
index 3f9ef82c381f6..826c3e22ec371 100644
--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IConversionExpression.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IConversionExpression.cs
@@ -318,11 +318,11 @@ static void Main(string[] args)
 IVariableDeclarationStatement (1 declarations) (OperationKind.VariableDeclarationStatement) (Syntax: 'object /*<b ... *</bind>*/;')
   IVariableDeclaration (1 variables) (OperationKind.VariableDeclaration) (Syntax: 'object /*<b ... *</bind>*/;')
     Variables: Local_1: System.Object o
-    Initializer: INullCoalescingExpression (OperationKind.NullCoalescingExpression, Type: System.Object) (Syntax: 'new object( ... Exception()')
-        Left: IObjectCreationExpression (Constructor: System.Object..ctor()) (OperationKind.ObjectCreationExpression, Type: System.Object) (Syntax: 'new object()')
+    Initializer: ICoalesceExpression (OperationKind.CoalesceExpression, Type: System.Object) (Syntax: 'new object( ... Exception()')
+        Expression: IObjectCreationExpression (Constructor: System.Object..ctor()) (OperationKind.ObjectCreationExpression, Type: System.Object) (Syntax: 'new object()')
             Arguments(0)
             Initializer: null
-        Right: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Object) (Syntax: 'throw new Exception()')
+        WhenNull: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Object) (Syntax: 'throw new Exception()')
             Conversion: CommonConversion (Exists: True, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
             Operand: IThrowExpression (OperationKind.ThrowExpression, Type: null) (Syntax: 'throw new Exception()')
                 IObjectCreationExpression (Constructor: System.Exception..ctor()) (OperationKind.ObjectCreationExpression, Type: System.Exception) (Syntax: 'new Exception()')
@@ -342,7 +342,7 @@ static void Main(string[] args)
                     OperationSelector = (operation) =>
                     {
                         var initializer = ((IVariableDeclarationStatement)operation).Declarations.Single().Initializer;
-                        return (IConversionExpression)((INullCoalescingExpression)initializer).SecondaryOperand;
+                        return (IConversionExpression)((ICoalesceExpression)initializer).WhenNull;
                     }
                 }.Verify);
         }
diff --git a/src/Compilers/Core/Portable/Generated/Operations.xml.Generated.cs b/src/Compilers/Core/Portable/Generated/Operations.xml.Generated.cs
index 2db8a93319f5b..b2b3debc8adb9 100644
--- a/src/Compilers/Core/Portable/Generated/Operations.xml.Generated.cs
+++ b/src/Compilers/Core/Portable/Generated/Operations.xml.Generated.cs
@@ -3039,74 +3039,74 @@ internal sealed partial class LazyMethodBindingExpression : BaseMethodBindingExp
     /// <summary>
     /// Represents a null-coalescing expression.
     /// </summary>
-    internal abstract partial class BaseNullCoalescingExpression : Operation, INullCoalescingExpression
+    internal abstract partial class BaseCoalesceExpression : Operation, ICoalesceExpression
     {
-        protected BaseNullCoalescingExpression(SemanticModel semanticModel, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) :
-                    base(OperationKind.NullCoalescingExpression, semanticModel, syntax, type, constantValue)
+        protected BaseCoalesceExpression(SemanticModel semanticModel, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) :
+                    base(OperationKind.CoalesceExpression, semanticModel, syntax, type, constantValue)
         {
         }
 
-        protected abstract IOperation PrimaryOperandImpl { get; }
-        protected abstract IOperation SecondaryOperandImpl { get; }
+        protected abstract IOperation ExpressionImpl { get; }
+        protected abstract IOperation WhenNullImpl { get; }
         public override IEnumerable<IOperation> Children
         {
             get
             {
-                yield return PrimaryOperand;
-                yield return SecondaryOperand;
+                yield return Expression;
+                yield return WhenNull;
             }
         }
         /// <summary>
         /// Value to be unconditionally evaluated.
         /// </summary>
-        public IOperation PrimaryOperand => Operation.SetParentOperation(PrimaryOperandImpl, this);
+        public IOperation Expression => Operation.SetParentOperation(ExpressionImpl, this);
         /// <summary>
-        /// Value to be evaluated if Primary evaluates to null/Nothing.
+        /// Value to be evaluated if <see cref="Expression"/> evaluates to null/Nothing.
         /// </summary>
-        public IOperation SecondaryOperand => Operation.SetParentOperation(SecondaryOperandImpl, this);
+        public IOperation WhenNull => Operation.SetParentOperation(WhenNullImpl, this);
         public override void Accept(OperationVisitor visitor)
         {
-            visitor.VisitNullCoalescingExpression(this);
+            visitor.VisitCoalesceExpression(this);
         }
         public override TResult Accept<TArgument, TResult>(OperationVisitor<TArgument, TResult> visitor, TArgument argument)
         {
-            return visitor.VisitNullCoalescingExpression(this, argument);
+            return visitor.VisitCoalesceExpression(this, argument);
         }
     }
 
     /// <summary>
     /// Represents a null-coalescing expression.
     /// </summary>
-    internal sealed partial class NullCoalescingExpression : BaseNullCoalescingExpression, INullCoalescingExpression
+    internal sealed partial class CoalesceExpression : BaseCoalesceExpression, ICoalesceExpression
     {
-        public NullCoalescingExpression(IOperation primaryOperand, IOperation secondaryOperand, SemanticModel semanticModel, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) :
+        public CoalesceExpression(IOperation expression, IOperation whenNull, SemanticModel semanticModel, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) :
             base(semanticModel, syntax, type, constantValue)
         {
-            PrimaryOperandImpl = primaryOperand;
-            SecondaryOperandImpl = secondaryOperand;
+            ExpressionImpl = expression;
+            WhenNullImpl = whenNull;
         }
 
-        protected override IOperation PrimaryOperandImpl { get; }
-        protected override IOperation SecondaryOperandImpl { get; }
+        protected override IOperation ExpressionImpl { get; }
+        protected override IOperation WhenNullImpl { get; }
     }
 
     /// <summary>
     /// Represents a null-coalescing expression.
     /// </summary>
-    internal sealed partial class LazyNullCoalescingExpression : BaseNullCoalescingExpression, INullCoalescingExpression
+    internal sealed partial class LazyCoalesceExpression : BaseCoalesceExpression, ICoalesceExpression
     {
-        private readonly Lazy<IOperation> _lazyPrimaryOperand;
-        private readonly Lazy<IOperation> _lazySecondaryOperand;
+        private readonly Lazy<IOperation> _lazyExpression;
+        private readonly Lazy<IOperation> _lazyWhenNull;
 
-        public LazyNullCoalescingExpression(Lazy<IOperation> primaryOperand, Lazy<IOperation> secondaryOperand, SemanticModel semanticModel, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) : base(semanticModel, syntax, type, constantValue)
+        public LazyCoalesceExpression(Lazy<IOperation> expression, Lazy<IOperation> whenNull, SemanticModel semanticModel, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) : base(semanticModel, syntax, type, constantValue)
         {
-            _lazyPrimaryOperand = primaryOperand ?? throw new System.ArgumentNullException(nameof(primaryOperand));
-            _lazySecondaryOperand = secondaryOperand ?? throw new System.ArgumentNullException(nameof(secondaryOperand));
+            _lazyExpression = expression ?? throw new System.ArgumentNullException(nameof(expression));
+            _lazyWhenNull = whenNull ?? throw new System.ArgumentNullException(nameof(whenNull));
         }
 
-        protected override IOperation PrimaryOperandImpl => _lazyPrimaryOperand.Value;
+        protected override IOperation ExpressionImpl => _lazyExpression.Value;
 
-        protected override IOperation SecondaryOperandImpl => _lazySecondaryOperand.Value;
+        protected override IOperation WhenNullImpl => _lazyWhenNull.Value;
     }
 
     /// <summary>
diff --git a/src/Compilers/Core/Portable/Operations/INullCoalescingExpression.cs b/src/Compilers/Core/Portable/Operations/ICoalesceExpression.cs
similarity index 75%
rename from src/Compilers/Core/Portable/Operations/INullCoalescingExpression.cs
rename to src/Compilers/Core/Portable/Operations/ICoalesceExpression.cs
index 9f64b19bf8df0..197933ede9db0 100644
--- a/src/Compilers/Core/Portable/Operations/INullCoalescingExpression.cs
+++ b/src/Compilers/Core/Portable/Operations/ICoalesceExpression.cs
@@ -11,16 +11,16 @@ namespace Microsoft.CodeAnalysis.Semantics
     /// This interface is reserved for implementation by its associated APIs. We reserve the right to
     /// change it in the future.
     /// </remarks>
-    public interface INullCoalescingExpression : IOperation
+    public interface ICoalesceExpression : IOperation
     {
         /// <summary>
         /// Value to be unconditionally evaluated.
         /// </summary>
-        IOperation PrimaryOperand { get; }
+        IOperation Expression { get; }
         /// <summary>
-        /// Value to be evaluated if Primary evaluates to null/Nothing.
+        /// Value to be evaluated if <see cref="Expression"/> evaluates to null/Nothing.
         /// </summary>
-        IOperation SecondaryOperand { get; }
+        IOperation WhenNull { get; }
     }
 }
 
diff --git a/src/Compilers/Core/Portable/Operations/OperationCloner.cs b/src/Compilers/Core/Portable/Operations/OperationCloner.cs
index 038de6c65fd1c..29ff7552bbcef 100644
--- a/src/Compilers/Core/Portable/Operations/OperationCloner.cs
+++ b/src/Compilers/Core/Portable/Operations/OperationCloner.cs
@@ -274,9 +274,9 @@ public override IOperation VisitConditionalChoiceExpression(IConditionalChoiceEx
             return new ConditionalChoiceExpression(Visit(operation.Condition), Visit(operation.IfTrueValue), Visit(operation.IfFalseValue), ((Operation)operation).SemanticModel, operation.Syntax, operation.Type, operation.ConstantValue);
         }
 
-        public override IOperation VisitNullCoalescingExpression(INullCoalescingExpression operation, object argument)
+        public override IOperation VisitCoalesceExpression(ICoalesceExpression operation, object argument)
         {
-            return new NullCoalescingExpression(Visit(operation.PrimaryOperand), Visit(operation.SecondaryOperand), ((Operation)operation).SemanticModel, operation.Syntax, operation.Type, operation.ConstantValue);
+            return new CoalesceExpression(Visit(operation.Expression), Visit(operation.WhenNull), ((Operation)operation).SemanticModel, operation.Syntax, operation.Type, operation.ConstantValue);
         }
 
         public override IOperation VisitIsTypeExpression(IIsTypeExpression operation, object argument)
diff --git a/src/Compilers/Core/Portable/Operations/OperationKind.cs b/src/Compilers/Core/Portable/Operations/OperationKind.cs
index f0a17227330cd..5023d3c517a72 100644
--- a/src/Compilers/Core/Portable/Operations/OperationKind.cs
+++ b/src/Compilers/Core/Portable/Operations/OperationKind.cs
@@ -96,8 +96,8 @@ public enum OperationKind
         BinaryOperatorExpression = 0x10e,
         /// <summary>Indicates an <see cref="IConditionalChoiceExpression"/>.</summary>
         ConditionalChoiceExpression = 0x10f,
-        /// <summary>Indicates an <see cref="INullCoalescingExpression"/>.</summary>
-        NullCoalescingExpression = 0x110,
+        /// <summary>Indicates an <see cref="ICoalesceExpression"/>.</summary>
+        CoalesceExpression = 0x110,
         /// <summary>Indicates an <see cref="ILambdaExpression"/>.</summary>
         LambdaExpression = 0x111,
         /// <summary>Indicates an <see cref="IObjectCreationExpression"/>.</summary>
diff --git a/src/Compilers/Core/Portable/Operations/OperationVisitor.cs b/src/Compilers/Core/Portable/Operations/OperationVisitor.cs
index 56c1f3b4db093..65d6ffdf9c4ba 100644
--- a/src/Compilers/Core/Portable/Operations/OperationVisitor.cs
+++ b/src/Compilers/Core/Portable/Operations/OperationVisitor.cs
@@ -270,7 +270,7 @@ public virtual void VisitConditionalChoiceExpression(IConditionalChoiceExpressio
             DefaultVisit(operation);
         }
 
-        public virtual void VisitNullCoalescingExpression(INullCoalescingExpression operation)
+        public virtual void VisitCoalesceExpression(ICoalesceExpression operation)
         {
             DefaultVisit(operation);
         }
@@ -740,7 +740,7 @@ public virtual TResult VisitConditionalChoiceExpression(IConditionalChoiceExpres
             return DefaultVisit(operation, argument);
         }
 
-        public virtual TResult VisitNullCoalescingExpression(INullCoalescingExpression operation, TArgument argument)
+        public virtual TResult VisitCoalesceExpression(ICoalesceExpression operation, TArgument argument)
         {
             return DefaultVisit(operation, argument);
         }
diff --git a/src/Compilers/Core/Portable/PublicAPI.Unshipped.txt b/src/Compilers/Core/Portable/PublicAPI.Unshipped.txt
index a9d2055d6d0f1..a8b3b08991570 100644
--- a/src/Compilers/Core/Portable/PublicAPI.Unshipped.txt
+++ b/src/Compilers/Core/Portable/PublicAPI.Unshipped.txt
@@ -101,7 +101,7 @@ Microsoft.CodeAnalysis.OperationKind.MemberInitializerExpression = 289 -> Micros
 Microsoft.CodeAnalysis.OperationKind.MethodBindingExpression = 265 -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.OperationKind.NameOfExpression = 291 -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.OperationKind.None = 0 -> Microsoft.CodeAnalysis.OperationKind
-Microsoft.CodeAnalysis.OperationKind.NullCoalescingExpression = 272 -> Microsoft.CodeAnalysis.OperationKind
+Microsoft.CodeAnalysis.OperationKind.CoalesceExpression = 272 -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.OperationKind.ObjectCreationExpression = 274 -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.OperationKind.ObjectOrCollectionInitializerExpression = 288 -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.OperationKind.OmittedArgumentExpression = 768 -> Microsoft.CodeAnalysis.OperationKind
@@ -512,9 +512,9 @@ Microsoft.CodeAnalysis.Semantics.IMethodBindingExpression.IsVirtual.get -> bool
 Microsoft.CodeAnalysis.Semantics.IMethodBindingExpression.Method.get -> Microsoft.CodeAnalysis.IMethodSymbol
 Microsoft.CodeAnalysis.Semantics.INameOfExpression
 Microsoft.CodeAnalysis.Semantics.INameOfExpression.Argument.get -> Microsoft.CodeAnalysis.IOperation
-Microsoft.CodeAnalysis.Semantics.INullCoalescingExpression
-Microsoft.CodeAnalysis.Semantics.INullCoalescingExpression.PrimaryOperand.get -> Microsoft.CodeAnalysis.IOperation
-Microsoft.CodeAnalysis.Semantics.INullCoalescingExpression.SecondaryOperand.get -> Microsoft.CodeAnalysis.IOperation
+Microsoft.CodeAnalysis.Semantics.ICoalesceExpression
+Microsoft.CodeAnalysis.Semantics.ICoalesceExpression.Expression.get -> Microsoft.CodeAnalysis.IOperation
+Microsoft.CodeAnalysis.Semantics.ICoalesceExpression.WhenNull.get -> Microsoft.CodeAnalysis.IOperation
 Microsoft.CodeAnalysis.Semantics.IObjectCreationExpression
 Microsoft.CodeAnalysis.Semantics.IObjectCreationExpression.Constructor.get -> Microsoft.CodeAnalysis.IMethodSymbol
 Microsoft.CodeAnalysis.Semantics.IObjectCreationExpression.Initializer.get -> Microsoft.CodeAnalysis.Semantics.IObjectOrCollectionInitializerExpression
@@ -827,7 +827,7 @@ virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitLockStatement(Mic
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitMemberInitializerExpression(Microsoft.CodeAnalysis.Semantics.IMemberInitializerExpression operation) -> void
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitMethodBindingExpression(Microsoft.CodeAnalysis.Semantics.IMethodBindingExpression operation) -> void
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitNameOfExpression(Microsoft.CodeAnalysis.Semantics.INameOfExpression operation) -> void
-virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitNullCoalescingExpression(Microsoft.CodeAnalysis.Semantics.INullCoalescingExpression operation) -> void
+virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitCoalesceExpression(Microsoft.CodeAnalysis.Semantics.ICoalesceExpression operation) -> void
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitObjectCreationExpression(Microsoft.CodeAnalysis.Semantics.IObjectCreationExpression operation) -> void
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitObjectOrCollectionInitializerExpression(Microsoft.CodeAnalysis.Semantics.IObjectOrCollectionInitializerExpression operation) -> void
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitOmittedArgumentExpression(Microsoft.CodeAnalysis.Semantics.IOmittedArgumentExpression operation) -> void
@@ -917,7 +917,7 @@ virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.Vi
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitMemberInitializerExpression(Microsoft.CodeAnalysis.Semantics.IMemberInitializerExpression operation, TArgument argument) -> TResult
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitMethodBindingExpression(Microsoft.CodeAnalysis.Semantics.IMethodBindingExpression operation, TArgument argument) -> TResult
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitNameOfExpression(Microsoft.CodeAnalysis.Semantics.INameOfExpression operation, TArgument argument) -> TResult
-virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitNullCoalescingExpression(Microsoft.CodeAnalysis.Semantics.INullCoalescingExpression operation, TArgument argument) -> TResult
+virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitCoalesceExpression(Microsoft.CodeAnalysis.Semantics.ICoalesceExpression operation, TArgument argument) -> TResult
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitObjectCreationExpression(Microsoft.CodeAnalysis.Semantics.IObjectCreationExpression operation, TArgument argument) -> TResult
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitObjectOrCollectionInitializerExpression(Microsoft.CodeAnalysis.Semantics.IObjectOrCollectionInitializerExpression operation, TArgument argument) -> TResult
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitOmittedArgumentExpression(Microsoft.CodeAnalysis.Semantics.IOmittedArgumentExpression operation, TArgument argument) -> TResult
diff --git a/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb b/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
index 8eed84d14b050..a82baea454099 100644
--- a/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
+++ b/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
@@ -443,13 +443,13 @@ Namespace Microsoft.CodeAnalysis.Semantics
             Return New LazyBinaryOperatorExpression(binaryOperationKind, leftOperand, rightOperand, isLifted, usesOperatorMethod, operatorMethod, _semanticModel, syntax, type, constantValue)
         End Function
 
-        Private Function CreateBoundBinaryConditionalExpressionOperation(boundBinaryConditionalExpression As BoundBinaryConditionalExpression) As INullCoalescingExpression
-            Dim primaryOperand As Lazy(Of IOperation) = New Lazy(Of IOperation)(Function() Create(boundBinaryConditionalExpression.TestExpression))
-            Dim secondaryOperand As Lazy(Of IOperation) = New Lazy(Of IOperation)(Function() Create(boundBinaryConditionalExpression.ElseExpression))
+        Private Function CreateBoundBinaryConditionalExpressionOperation(boundBinaryConditionalExpression As BoundBinaryConditionalExpression) As ICoalesceExpression
+            Dim expression As Lazy(Of IOperation) = New Lazy(Of IOperation)(Function() Create(boundBinaryConditionalExpression.TestExpression))
+            Dim whenNull As Lazy(Of IOperation) = New Lazy(Of IOperation)(Function() Create(boundBinaryConditionalExpression.ElseExpression))
             Dim syntax As SyntaxNode = boundBinaryConditionalExpression.Syntax
             Dim type As ITypeSymbol = boundBinaryConditionalExpression.Type
             Dim constantValue As [Optional](Of Object) = ConvertToOptional(boundBinaryConditionalExpression.ConstantValueOpt)
-            Return New LazyNullCoalescingExpression(primaryOperand, secondaryOperand, _semanticModel, syntax, type, constantValue)
+            Return New LazyCoalesceExpression(expression, whenNull, _semanticModel, syntax, type, constantValue)
         End Function
 
         Private Function CreateBoundUserDefinedShortCircuitingOperatorOperation(boundUserDefinedShortCircuitingOperator As BoundUserDefinedShortCircuitingOperator) As IBinaryOperatorExpression
diff --git a/src/Features/Core/Portable/InitializeParameter/AbstractAddParameterCheckCodeRefactoringProvider.cs b/src/Features/Core/Portable/InitializeParameter/AbstractAddParameterCheckCodeRefactoringProvider.cs
index cbc58c586469f..86c89802aaae2 100644
--- a/src/Features/Core/Portable/InitializeParameter/AbstractAddParameterCheckCodeRefactoringProvider.cs
+++ b/src/Features/Core/Portable/InitializeParameter/AbstractAddParameterCheckCodeRefactoringProvider.cs
@@ -105,10 +105,10 @@ internal abstract partial class AbstractAddParameterCheckCodeRefactoringProvider
             foreach (var coalesceNode in syntax.DescendantNodes().OfType<TBinaryExpressionSyntax>())
             {
                 var operation = GetOperation(semanticModel, coalesceNode, cancellationToken);
-                if (operation is INullCoalescingExpression coalesceExpression)
+                if (operation is ICoalesceExpression coalesceExpression)
                 {
-                    if (IsParameterReference(coalesceExpression.PrimaryOperand, parameter) &&
-                        syntaxFacts.IsThrowExpression(coalesceExpression.SecondaryOperand.Syntax))
+                    if (IsParameterReference(coalesceExpression.Expression, parameter) &&
+                        syntaxFacts.IsThrowExpression(coalesceExpression.WhenNull.Syntax))
                     {
                         return true;
                     }
diff --git a/src/Features/Core/Portable/InitializeParameter/AbstractInitializeMemberFromParameterCodeRefactoringProviderMemberCreation.cs b/src/Features/Core/Portable/InitializeParameter/AbstractInitializeMemberFromParameterCodeRefactoringProviderMemberCreation.cs
index a66107af87256..8c74a89e48d9e 100644
--- a/src/Features/Core/Portable/InitializeParameter/AbstractInitializeMemberFromParameterCodeRefactoringProviderMemberCreation.cs
+++ b/src/Features/Core/Portable/InitializeParameter/AbstractInitializeMemberFromParameterCodeRefactoringProviderMemberCreation.cs
@@ -391,8 +391,8 @@ private IOperation TryFindFieldOrPropertyAssignmentStatement(IParameterSymbol pa
                 return true;
             }
 
-            if (UnwrapImplicitConversion(assignmentExpression.Value) is INullCoalescingExpression coalesceExpression &&
-                IsParameterReference(coalesceExpression.PrimaryOperand, parameter))
+            if (UnwrapImplicitConversion(assignmentExpression.Value) is ICoalesceExpression coalesceExpression &&
+                IsParameterReference(coalesceExpression.Expression, parameter))
             {
                 // We already have a member initialized with this parameter like:
                 //      this.field = parameter ?? ...
diff --git a/src/Test/Utilities/Portable/Compilation/OperationTreeVerifier.cs b/src/Test/Utilities/Portable/Compilation/OperationTreeVerifier.cs
index 25ba77ef569b7..5fbb7620ebbb1 100644
--- a/src/Test/Utilities/Portable/Compilation/OperationTreeVerifier.cs
+++ b/src/Test/Utilities/Portable/Compilation/OperationTreeVerifier.cs
@@ -865,13 +865,13 @@ public override void VisitConditionalChoiceExpression(IConditionalChoiceExpressi
             Visit(operation.IfFalseValue, "IfFalse");
         }
 
-        public override void VisitNullCoalescingExpression(INullCoalescingExpression operation)
+        public override void VisitCoalesceExpression(ICoalesceExpression operation)
         {
-            LogString(nameof(INullCoalescingExpression));
+            LogString(nameof(ICoalesceExpression));
             LogCommonPropertiesAndNewLine(operation);
 
-            Visit(operation.PrimaryOperand, "Left");
-            Visit(operation.SecondaryOperand, "Right");
+            Visit(operation.Expression, "Expression");
+            Visit(operation.WhenNull, "WhenNull");
         }
 
         public override void VisitIsTypeExpression(IIsTypeExpression operation)
diff --git a/src/Test/Utilities/Portable/Compilation/TestOperationWalker.cs b/src/Test/Utilities/Portable/Compilation/TestOperationWalker.cs
index ae9cdd4978e9c..31dfefd8af814 100644
--- a/src/Test/Utilities/Portable/Compilation/TestOperationWalker.cs
+++ b/src/Test/Utilities/Portable/Compilation/TestOperationWalker.cs
@@ -372,9 +372,9 @@ public override void VisitConditionalChoiceExpression(IConditionalChoiceExpressi
             base.VisitConditionalChoiceExpression(operation);
         }
 
-        public override void VisitNullCoalescingExpression(INullCoalescingExpression operation)
+        public override void VisitCoalesceExpression(ICoalesceExpression operation)
         {
-            base.VisitNullCoalescingExpression(operation);
+            base.VisitCoalesceExpression(operation);
         }
 
         public override void VisitIsTypeExpression(IIsTypeExpression operation)

From 557f12283269614ac96e1dc2025187aa813d653f Mon Sep 17 00:00:00 2001
From: Fredric Silberberg <frsilb@microsoft.com>
Date: Fri, 11 Aug 2017 15:22:21 -0700
Subject: [PATCH 41/77] Refactored ILambdaExpression to
 IAnonymousFunctionExpression, Signature to Symbol.

---
 .../Operations/CSharpOperationFactory.cs      | 10 ++---
 ...tionTests_IAnonymousFunctionExpression.cs} | 24 ++++++------
 .../IOperationTests_IConversionExpression.cs  | 32 +++++++--------
 ...nTests_IDynamicObjectCreationExpression.cs |  2 +-
 .../IOperationTests_IForLoopStatement.cs      | 16 ++++----
 ...tionTests_IParameterReferenceExpression.cs |  4 +-
 .../IOperationTests_InvalidExpression.cs      |  4 +-
 .../Symbols/AnonymousTypesSemanticsTests.cs   |  2 +-
 .../Generated/Operations.xml.Generated.cs     | 39 ++++++-------------
 ...ion.cs => IAnonymousFunctionExpression.cs} | 10 ++---
 .../Portable/Operations/OperationCloner.cs    |  4 +-
 .../Core/Portable/Operations/OperationKind.cs |  4 +-
 .../Portable/Operations/OperationVisitor.cs   |  4 +-
 .../Core/Portable/PublicAPI.Unshipped.txt     | 12 +++---
 .../Operations/VisualBasicOperationFactory.vb |  6 +--
 .../Binding/BindingObjectInitializerTests.vb  |  6 +--
 .../IOperationTests_IConversionExpression.vb  | 16 ++++----
 ...tionTests_IParameterReferenceExpression.vb |  2 +-
 .../IOperationTests_InvalidExpression.vb      |  2 +-
 .../Semantic/Semantics/AnonymousTypesTests.vb | 18 ++++-----
 .../Semantic/Semantics/SelectCaseTests.vb     |  2 +-
 .../Compilation/OperationTreeVerifier.cs      |  8 ++--
 .../Compilation/TestOperationWalker.cs        |  6 +--
 .../Diagnostics/OperationTestAnalyzer.cs      |  4 +-
 24 files changed, 111 insertions(+), 126 deletions(-)
 rename src/Compilers/CSharp/Test/Semantic/IOperation/{IOperationTests_ILambdaExpression.cs => IOperationTests_IAnonymousFunctionExpression.cs} (82%)
 rename src/Compilers/Core/Portable/Operations/{ILambdaExpression.cs => IAnonymousFunctionExpression.cs} (67%)

diff --git a/src/Compilers/CSharp/Portable/Operations/CSharpOperationFactory.cs b/src/Compilers/CSharp/Portable/Operations/CSharpOperationFactory.cs
index bd1721ce525c0..306d4af345964 100644
--- a/src/Compilers/CSharp/Portable/Operations/CSharpOperationFactory.cs
+++ b/src/Compilers/CSharp/Portable/Operations/CSharpOperationFactory.cs
@@ -611,22 +611,22 @@ private IOperation CreateUnboundLambdaOperation(UnboundLambda unboundLambda)
             // We are counting on the fact that will do the error recovery and actually create the BoundLambda node appropriate for
             // this syntax node.
             var lambdaOperation = _semanticModel.GetOperationInternal(unboundLambda.Syntax);
-            Debug.Assert(lambdaOperation.Kind == OperationKind.LambdaExpression);
+            Debug.Assert(lambdaOperation.Kind == OperationKind.AnonymousFunctionExpression);
             return lambdaOperation;
         }
 
-        private ILambdaExpression CreateBoundLambdaOperation(BoundLambda boundLambda)
+        private IAnonymousFunctionExpression CreateBoundLambdaOperation(BoundLambda boundLambda)
         {
-            IMethodSymbol signature = boundLambda.Symbol;
+            IMethodSymbol symbol = boundLambda.Symbol;
             Lazy<IBlockStatement> body = new Lazy<IBlockStatement>(() => (IBlockStatement)Create(boundLambda.Body));
             SyntaxNode syntax = boundLambda.Syntax;
             // This matches the SemanticModel implementation. This is because in VB, lambdas by themselves
             // do not have a type. To get the type of a lambda expression in the SemanticModel, you need to look at
             // TypeInfo.ConvertedType, rather than TypeInfo.Type. We replicate that behavior here. To get the type of
-            // an ILambdaExpression, you need to look at the parent IConversionExpression.
+            // an IAnonymousFunctionExpression, you need to look at the parent IConversionExpression.
             ITypeSymbol type = null;
             Optional<object> constantValue = ConvertToOptional(boundLambda.ConstantValue);
-            return new LazyLambdaExpression(signature, body, _semanticModel, syntax, type, constantValue);
+            return new LazyAnonymousFunctionExpression(symbol, body, _semanticModel, syntax, type, constantValue);
         }
 
         private ILocalFunctionStatement CreateBoundLocalFunctionStatementOperation(BoundLocalFunctionStatement boundLocalFunctionStatement)
diff --git a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_ILambdaExpression.cs b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IAnonymousFunctionExpression.cs
similarity index 82%
rename from src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_ILambdaExpression.cs
rename to src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IAnonymousFunctionExpression.cs
index 24ba5e3ae4b5c..d03618490dd96 100644
--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_ILambdaExpression.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IAnonymousFunctionExpression.cs
@@ -12,7 +12,7 @@ public partial class IOperationTests : SemanticModelTestBase
     {
         [CompilerTrait(CompilerFeature.IOperation)]
         [Fact]
-        public void ILambdaExpression_BoundLambda_HasValidLambdaExpressionTree()
+        public void IAnonymousFunctionExpression_BoundLambda_HasValidLambdaExpressionTree()
         {
             string source = @"
 using System;
@@ -35,7 +35,7 @@ static void F()
     Variables: Local_1: System.Action x
     Initializer: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Action) (Syntax: '() => F()')
         Conversion: CommonConversion (Exists: True, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-        Operand: ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null) (Syntax: '() => F()')
+        Operand: IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null) (Syntax: '() => F()')
             IBlockStatement (2 statements) (OperationKind.BlockStatement) (Syntax: 'F()')
               IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'F()')
                 Expression: IInvocationExpression (void Program.F()) (OperationKind.InvocationExpression, Type: System.Void) (Syntax: 'F()')
@@ -51,7 +51,7 @@ static void F()
 
         [CompilerTrait(CompilerFeature.IOperation)]
         [Fact]
-        public void ILambdaExpression_UnboundLambdaAsVar_HasValidLambdaExpressionTree()
+        public void IAnonymousFunctionExpression_UnboundLambdaAsVar_HasValidLambdaExpressionTree()
         {
             string source = @"
 using System;
@@ -72,7 +72,7 @@ static void F()
 IVariableDeclarationStatement (1 declarations) (OperationKind.VariableDeclarationStatement, IsInvalid) (Syntax: 'var x /*<bi ... *</bind>*/;')
   IVariableDeclaration (1 variables) (OperationKind.VariableDeclaration, IsInvalid) (Syntax: 'var x /*<bi ... *</bind>*/;')
     Variables: Local_1: var x
-    Initializer: ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null, IsInvalid) (Syntax: '() => F()')
+    Initializer: IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null, IsInvalid) (Syntax: '() => F()')
         IBlockStatement (1 statements) (OperationKind.BlockStatement, IsInvalid) (Syntax: 'F()')
           IExpressionStatement (OperationKind.ExpressionStatement, IsInvalid) (Syntax: 'F()')
             Expression: IInvocationExpression (void Program.F()) (OperationKind.InvocationExpression, Type: System.Void, IsInvalid) (Syntax: 'F()')
@@ -90,7 +90,7 @@ static void F()
 
         [CompilerTrait(CompilerFeature.IOperation)]
         [Fact]
-        public void ILambdaExpression_UnboundLambdaAsDelegate_HasValidLambdaExpressionTree()
+        public void IAnonymousFunctionExpression_UnboundLambdaAsDelegate_HasValidLambdaExpressionTree()
         {
             string source = @"
 using System;
@@ -113,7 +113,7 @@ static void F()
     Variables: Local_1: System.Action<System.Int32> x
     Initializer: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Action<System.Int32>, IsInvalid) (Syntax: '() => F()')
         Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-        Operand: ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null, IsInvalid) (Syntax: '() => F()')
+        Operand: IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null, IsInvalid) (Syntax: '() => F()')
             IBlockStatement (1 statements) (OperationKind.BlockStatement, IsInvalid) (Syntax: 'F()')
               IExpressionStatement (OperationKind.ExpressionStatement, IsInvalid) (Syntax: 'F()')
                 Expression: IInvocationExpression (void Program.F()) (OperationKind.InvocationExpression, Type: System.Void, IsInvalid) (Syntax: 'F()')
@@ -131,7 +131,7 @@ static void F()
 
         [CompilerTrait(CompilerFeature.IOperation)]
         [Fact]
-        public void ILambdaExpression_UnboundLambda_ReferenceEquality()
+        public void IAnonymousFunctionExpression_UnboundLambda_ReferenceEquality()
         {
             string source = @"
 using System;
@@ -157,19 +157,19 @@ static void F()
             var lambdaSyntax = (LambdaExpressionSyntax)variableDeclaration.Variables.Single().Initializer.Value;
 
             var variableDeclarationOperation = (IVariableDeclarationStatement)semanticModel.GetOperationInternal(variableDeclaration);
-            var variableTreeLambdaOperation = (ILambdaExpression)variableDeclarationOperation.Declarations.Single().Initializer;
-            var lambdaOperation = (ILambdaExpression)semanticModel.GetOperationInternal(lambdaSyntax);
+            var variableTreeLambdaOperation = (IAnonymousFunctionExpression)variableDeclarationOperation.Declarations.Single().Initializer;
+            var lambdaOperation = (IAnonymousFunctionExpression)semanticModel.GetOperationInternal(lambdaSyntax);
 
             // Assert that both ways of getting to the lambda (requesting the lambda directly, and requesting via the lambda syntax)
             // return the same bound node.
             Assert.Same(variableTreeLambdaOperation, lambdaOperation);
 
             var variableDeclarationOperationSecondRequest = (IVariableDeclarationStatement)semanticModel.GetOperationInternal(variableDeclaration);
-            var variableTreeLambdaOperationSecondRequest = (ILambdaExpression)variableDeclarationOperation.Declarations.Single().Initializer;
-            var lambdaOperationSecondRequest = (ILambdaExpression)semanticModel.GetOperationInternal(lambdaSyntax);
+            var variableTreeLambdaOperationSecondRequest = (IAnonymousFunctionExpression)variableDeclarationOperation.Declarations.Single().Initializer;
+            var lambdaOperationSecondRequest = (IAnonymousFunctionExpression)semanticModel.GetOperationInternal(lambdaSyntax);
 
             // Assert that, when request the variable declaration or the lambda for a second time, there is no rebinding of the
-            // underlying UnboundLambda, and we get the same ILambdaExpression as before
+            // underlying UnboundLambda, and we get the same IAnonymousFunctionExpression as before
             Assert.Same(variableTreeLambdaOperation, variableTreeLambdaOperationSecondRequest);
             Assert.Same(lambdaOperation, lambdaOperationSecondRequest);
         }
diff --git a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IConversionExpression.cs b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IConversionExpression.cs
index 3f9ef82c381f6..fbfbe774b21ce 100644
--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IConversionExpression.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IConversionExpression.cs
@@ -1614,7 +1614,7 @@ void Main()
     Variables: Local_1: Program.DType d1
     Initializer: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: Program.DType) (Syntax: '() => { }')
         Conversion: CommonConversion (Exists: True, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-        Operand: ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null) (Syntax: '() => { }')
+        Operand: IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null) (Syntax: '() => { }')
             IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: '{ }')
               IReturnStatement (OperationKind.ReturnStatement) (Syntax: '{ }')
                 ReturnedValue: null
@@ -1645,7 +1645,7 @@ void Main()
     Variables: Local_1: Program.DType d1
     Initializer: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: Program.DType, IsInvalid) (Syntax: '(string s) => { }')
         Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-        Operand: ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null, IsInvalid) (Syntax: '(string s) => { }')
+        Operand: IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null, IsInvalid) (Syntax: '(string s) => { }')
             IBlockStatement (0 statements) (OperationKind.BlockStatement, IsInvalid) (Syntax: '{ }')
 ";
             var expectedDiagnostics = new DiagnosticDescription[] {
@@ -1679,7 +1679,7 @@ void Main()
     Variables: Local_1: Program.DType d1
     Initializer: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: Program.DType, IsInvalid) (Syntax: '() =>/*</bind>*/')
         Conversion: CommonConversion (Exists: True, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-        Operand: ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null, IsInvalid) (Syntax: '() =>/*</bind>*/')
+        Operand: IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null, IsInvalid) (Syntax: '() =>/*</bind>*/')
             IBlockStatement (2 statements) (OperationKind.BlockStatement, IsInvalid) (Syntax: '')
               IExpressionStatement (OperationKind.ExpressionStatement, IsInvalid) (Syntax: '')
                 Expression: IInvalidExpression (OperationKind.InvalidExpression, Type: ?, IsInvalid) (Syntax: '')
@@ -1719,7 +1719,7 @@ static void Main(string[] args)
             string expectedOperationTree = @"
 IOperation:  (OperationKind.None) (Syntax: 'new Action(() => { })')
   Children(1):
-      ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null) (Syntax: '() => { }')
+      IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null) (Syntax: '() => { }')
         IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: '{ }')
           IReturnStatement (OperationKind.ReturnStatement) (Syntax: '{ }')
             ReturnedValue: null
@@ -2989,7 +2989,7 @@ void M1()
     Variables: Local_1: System.Action a
     Initializer: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Action) (Syntax: 'delegate { }')
         Conversion: CommonConversion (Exists: True, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-        Operand: ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null) (Syntax: 'delegate { }')
+        Operand: IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null) (Syntax: 'delegate { }')
             IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: '{ }')
               IReturnStatement (OperationKind.ReturnStatement) (Syntax: '{ }')
                 ReturnedValue: null
@@ -3021,7 +3021,7 @@ void M1()
     Variables: Local_1: System.Action<System.Int32> a
     Initializer: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Action<System.Int32>) (Syntax: 'delegate(int i) { }')
         Conversion: CommonConversion (Exists: True, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-        Operand: ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null) (Syntax: 'delegate(int i) { }')
+        Operand: IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null) (Syntax: 'delegate(int i) { }')
             IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: '{ }')
               IReturnStatement (OperationKind.ReturnStatement) (Syntax: '{ }')
                 ReturnedValue: null
@@ -3053,7 +3053,7 @@ void M1()
     Variables: Local_1: System.Action<System.Int32> a
     Initializer: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Action<System.Int32>, IsInvalid) (Syntax: 'delegate() { }')
         Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-        Operand: ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null, IsInvalid) (Syntax: 'delegate() { }')
+        Operand: IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null, IsInvalid) (Syntax: 'delegate() { }')
             IBlockStatement (0 statements) (OperationKind.BlockStatement, IsInvalid) (Syntax: '{ }')
 ";
             var expectedDiagnostics = new DiagnosticDescription[] {
@@ -3217,7 +3217,7 @@ static void Main(string[] args)
     Variables: Local_1: System.Linq.Expressions.Expression<System.Func<System.Int32, System.Boolean>> exp
     Initializer: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Linq.Expressions.Expression<System.Func<System.Int32, System.Boolean>>) (Syntax: 'num => num < 5')
         Conversion: CommonConversion (Exists: True, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-        Operand: ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null) (Syntax: 'num => num < 5')
+        Operand: IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null) (Syntax: 'num => num < 5')
             IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: 'num < 5')
               IReturnStatement (OperationKind.ReturnStatement) (Syntax: 'num < 5')
                 ReturnedValue: IBinaryOperatorExpression (BinaryOperationKind.IntegerLessThan) (OperationKind.BinaryOperatorExpression, Type: System.Boolean) (Syntax: 'num < 5')
@@ -3250,7 +3250,7 @@ static void Main(string[] args)
   IVariableDeclaration (1 variables) (OperationKind.VariableDeclaration, IsInvalid) (Syntax: 'Expression< ... *</bind>*/;')
     Variables: Local_1: System.Linq.Expressions.Expression<System.Func<System.Int32, System.Boolean>> exp
     Initializer: IConversionExpression (ConversionKind.Invalid, Implicit) (OperationKind.ConversionExpression, Type: System.Linq.Expressions.Expression<System.Func<System.Int32, System.Boolean>>, IsInvalid) (Syntax: 'num => num')
-        ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null, IsInvalid) (Syntax: 'num => num')
+        IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null, IsInvalid) (Syntax: 'num => num')
           IBlockStatement (1 statements) (OperationKind.BlockStatement, IsInvalid) (Syntax: 'num')
             IReturnStatement (OperationKind.ReturnStatement, IsInvalid) (Syntax: 'num')
               IConversionExpression (ConversionKind.Invalid, Implicit) (OperationKind.ConversionExpression, Type: System.Boolean, IsInvalid) (Syntax: 'num')
@@ -3293,7 +3293,7 @@ static void Main(string[] args)
     Variables: Local_1: System.Linq.Expressions.Expression<System.Func<System.Int32, System.Boolean>> exp
     Initializer: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Linq.Expressions.Expression<System.Func<System.Int32, System.Boolean>>, IsInvalid) (Syntax: 'num =>/*</bind>*/')
         Conversion: CommonConversion (Exists: True, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-        Operand: ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null, IsInvalid) (Syntax: 'num =>/*</bind>*/')
+        Operand: IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null, IsInvalid) (Syntax: 'num =>/*</bind>*/')
             IBlockStatement (1 statements) (OperationKind.BlockStatement, IsInvalid) (Syntax: '')
               IReturnStatement (OperationKind.ReturnStatement, IsInvalid) (Syntax: '')
                 ReturnedValue: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Boolean, IsInvalid) (Syntax: '')
@@ -4902,7 +4902,7 @@ void M1()
     Variables: Local_1: System.Action a
     Initializer: IConversionExpression (Explicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Action) (Syntax: '(Action)(() => { })')
         Conversion: CommonConversion (Exists: True, IsIdentity: True, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-        Operand: ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null) (Syntax: '() => { }')
+        Operand: IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null) (Syntax: '() => { }')
             IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: '{ }')
               IReturnStatement (OperationKind.ReturnStatement) (Syntax: '{ }')
                 ReturnedValue: null
@@ -4933,7 +4933,7 @@ void M1()
     Variables: Local_1: System.Action a
     Initializer: IConversionExpression (Explicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Action, IsInvalid) (Syntax: '(Action)(() => 1)')
         Conversion: CommonConversion (Exists: True, IsIdentity: True, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-        Operand: ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null, IsInvalid) (Syntax: '() => 1')
+        Operand: IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null, IsInvalid) (Syntax: '() => 1')
             IBlockStatement (2 statements) (OperationKind.BlockStatement, IsInvalid) (Syntax: '1')
               IExpressionStatement (OperationKind.ExpressionStatement, IsInvalid) (Syntax: '1')
                 Expression: ILiteralExpression (Text: 1) (OperationKind.LiteralExpression, Type: System.Int32, Constant: 1, IsInvalid) (Syntax: '1')
@@ -4970,7 +4970,7 @@ void M1()
     Variables: Local_1: System.Action a
     Initializer: IConversionExpression (Explicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Action, IsInvalid) (Syntax: '(Action)((s ...  s) => { })')
         Conversion: CommonConversion (Exists: True, IsIdentity: True, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-        Operand: ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null, IsInvalid) (Syntax: '(string s) => { }')
+        Operand: IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null, IsInvalid) (Syntax: '(string s) => { }')
             IBlockStatement (0 statements) (OperationKind.BlockStatement, IsInvalid) (Syntax: '{ }')
 ";
             var expectedDiagnostics = new DiagnosticDescription[] {
@@ -5002,7 +5002,7 @@ void M1()
   Children(1):
       IConversionExpression (Explicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Action) (Syntax: '(Action)(() => { })')
         Conversion: CommonConversion (Exists: True, IsIdentity: True, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-        Operand: ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null) (Syntax: '() => { }')
+        Operand: IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null) (Syntax: '() => { }')
             IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: '{ }')
               IReturnStatement (OperationKind.ReturnStatement) (Syntax: '{ }')
                 ReturnedValue: null
@@ -5032,7 +5032,7 @@ void M1()
   Children(1):
       IConversionExpression (Explicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Action, IsInvalid) (Syntax: '(Action)(() => 1)')
         Conversion: CommonConversion (Exists: True, IsIdentity: True, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-        Operand: ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null, IsInvalid) (Syntax: '() => 1')
+        Operand: IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null, IsInvalid) (Syntax: '() => 1')
             IBlockStatement (2 statements) (OperationKind.BlockStatement, IsInvalid) (Syntax: '1')
               IExpressionStatement (OperationKind.ExpressionStatement, IsInvalid) (Syntax: '1')
                 Expression: ILiteralExpression (Text: 1) (OperationKind.LiteralExpression, Type: System.Int32, Constant: 1, IsInvalid) (Syntax: '1')
@@ -5068,7 +5068,7 @@ void M1()
   Children(1):
       IConversionExpression (Explicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Action, IsInvalid) (Syntax: '(Action)((s ...  s) => { })')
         Conversion: CommonConversion (Exists: True, IsIdentity: True, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-        Operand: ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null, IsInvalid) (Syntax: '(string s) => { }')
+        Operand: IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null, IsInvalid) (Syntax: '(string s) => { }')
             IBlockStatement (0 statements) (OperationKind.BlockStatement, IsInvalid) (Syntax: '{ }')
 ";
             var expectedDiagnostics = new DiagnosticDescription[] {
diff --git a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IDynamicObjectCreationExpression.cs b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IDynamicObjectCreationExpression.cs
index b113b2ff8d391..0195cedd8f22a 100644
--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IDynamicObjectCreationExpression.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IDynamicObjectCreationExpression.cs
@@ -310,7 +310,7 @@ public C(Action a, Action y)
   ApplicableSymbols(1):
     Symbol: C..ctor(System.Action a, System.Action y)
   Arguments(2):
-      ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null, IsInvalid) (Syntax: 'delegate { }')
+      IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null, IsInvalid) (Syntax: 'delegate { }')
         IBlockStatement (1 statements) (OperationKind.BlockStatement, IsInvalid) (Syntax: '{ }')
           IReturnStatement (OperationKind.ReturnStatement, IsInvalid) (Syntax: '{ }')
             ReturnedValue: null
diff --git a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IForLoopStatement.cs b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IForLoopStatement.cs
index 934286e1d5292..a962c15b7921f 100644
--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IForLoopStatement.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IForLoopStatement.cs
@@ -1398,7 +1398,7 @@ static void Main(string[] args)
                                                                       IArgument (ArgumentKind.Explicit, Matching Parameter: selector) (OperationKind.Argument) (Syntax: 'x.ToString()')
                                                                         IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Func<System.Char, <anonymous type: System.Char x, System.String z>>) (Syntax: 'x.ToString()')
                                                                           Conversion: CommonConversion (Exists: True, IsIdentity: True, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-                                                                          Operand: ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null) (Syntax: 'x.ToString()')
+                                                                          Operand: IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null) (Syntax: 'x.ToString()')
                                                                               IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: 'x.ToString()')
                                                                                 IReturnStatement (OperationKind.ReturnStatement) (Syntax: 'x.ToString()')
                                                                                   ReturnedValue: IObjectCreationExpression (Constructor: <anonymous type: System.Char x, System.String z>..ctor(System.Char x, System.String z)) (OperationKind.ObjectCreationExpression, Type: <anonymous type: System.Char x, System.String z>) (Syntax: 'let z = x.ToString()')
@@ -1421,7 +1421,7 @@ static void Main(string[] args)
                                                         IArgument (ArgumentKind.Explicit, Matching Parameter: selector) (OperationKind.Argument) (Syntax: 'z')
                                                           IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Func<<anonymous type: System.Char x, System.String z>, System.String>) (Syntax: 'z')
                                                             Conversion: CommonConversion (Exists: True, IsIdentity: True, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-                                                            Operand: ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null) (Syntax: 'z')
+                                                            Operand: IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null) (Syntax: 'z')
                                                                 IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: 'z')
                                                                   IReturnStatement (OperationKind.ReturnStatement) (Syntax: 'z')
                                                                     ReturnedValue: IOperation:  (OperationKind.None) (Syntax: 'z')
@@ -1432,7 +1432,7 @@ static void Main(string[] args)
                                           IArgument (ArgumentKind.Explicit, Matching Parameter: selector) (OperationKind.Argument) (Syntax: 'w')
                                             IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Func<System.String, System.String>) (Syntax: 'w')
                                               Conversion: CommonConversion (Exists: True, IsIdentity: True, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-                                              Operand: ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null) (Syntax: 'w')
+                                              Operand: IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null) (Syntax: 'w')
                                                   IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: 'w')
                                                     IReturnStatement (OperationKind.ReturnStatement) (Syntax: 'w')
                                                       ReturnedValue: IOperation:  (OperationKind.None) (Syntax: 'w')
@@ -1538,7 +1538,7 @@ private static IEnumerable<string> fun()
                                                                     IArgument (ArgumentKind.Explicit, Matching Parameter: selector) (OperationKind.Argument) (Syntax: 'x.ToString()')
                                                                       IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Func<System.Char, <anonymous type: System.Char x, System.String z>>) (Syntax: 'x.ToString()')
                                                                         Conversion: CommonConversion (Exists: True, IsIdentity: True, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-                                                                        Operand: ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null) (Syntax: 'x.ToString()')
+                                                                        Operand: IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null) (Syntax: 'x.ToString()')
                                                                             IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: 'x.ToString()')
                                                                               IReturnStatement (OperationKind.ReturnStatement) (Syntax: 'x.ToString()')
                                                                                 ReturnedValue: IObjectCreationExpression (Constructor: <anonymous type: System.Char x, System.String z>..ctor(System.Char x, System.String z)) (OperationKind.ObjectCreationExpression, Type: <anonymous type: System.Char x, System.String z>) (Syntax: 'let z = x.ToString()')
@@ -1561,7 +1561,7 @@ private static IEnumerable<string> fun()
                                                       IArgument (ArgumentKind.Explicit, Matching Parameter: selector) (OperationKind.Argument) (Syntax: 'z')
                                                         IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Func<<anonymous type: System.Char x, System.String z>, System.String>) (Syntax: 'z')
                                                           Conversion: CommonConversion (Exists: True, IsIdentity: True, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-                                                          Operand: ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null) (Syntax: 'z')
+                                                          Operand: IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null) (Syntax: 'z')
                                                               IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: 'z')
                                                                 IReturnStatement (OperationKind.ReturnStatement) (Syntax: 'z')
                                                                   ReturnedValue: IOperation:  (OperationKind.None) (Syntax: 'z')
@@ -1572,7 +1572,7 @@ private static IEnumerable<string> fun()
                                         IArgument (ArgumentKind.Explicit, Matching Parameter: selector) (OperationKind.Argument) (Syntax: 'w')
                                           IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Func<System.String, System.String>) (Syntax: 'w')
                                             Conversion: CommonConversion (Exists: True, IsIdentity: True, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-                                            Operand: ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null) (Syntax: 'w')
+                                            Operand: IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null) (Syntax: 'w')
                                                 IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: 'w')
                                                   IReturnStatement (OperationKind.ReturnStatement) (Syntax: 'w')
                                                     ReturnedValue: IOperation:  (OperationKind.None) (Syntax: 'w')
@@ -1613,7 +1613,7 @@ static void Main(string[] args)
             Left: ILocalReferenceExpression: e (OperationKind.LocalReferenceExpression, Type: System.Linq.Expressions.Expression<System.Func<System.Int32, System.Int32>>) (Syntax: 'e')
             Right: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Linq.Expressions.Expression<System.Func<System.Int32, System.Int32>>) (Syntax: 'x => x * x')
                 Conversion: CommonConversion (Exists: True, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-                Operand: ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null) (Syntax: 'x => x * x')
+                Operand: IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null) (Syntax: 'x => x * x')
                     IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: 'x * x')
                       IReturnStatement (OperationKind.ReturnStatement) (Syntax: 'x * x')
                         ReturnedValue: IBinaryOperatorExpression (BinaryOperationKind.IntegerMultiply) (OperationKind.BinaryOperatorExpression, Type: System.Int32) (Syntax: 'x * x')
@@ -1685,7 +1685,7 @@ static void Main(string[] args)
             Left: ILocalReferenceExpression: e (OperationKind.LocalReferenceExpression, Type: System.Linq.Expressions.Expression<System.Func<System.Int32, System.Int32>>) (Syntax: 'e')
             Right: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Linq.Expressions.Expression<System.Func<System.Int32, System.Int32>>) (Syntax: 'x => x * x')
                 Conversion: CommonConversion (Exists: True, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-                Operand: ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null) (Syntax: 'x => x * x')
+                Operand: IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null) (Syntax: 'x => x * x')
                     IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: 'x * x')
                       IReturnStatement (OperationKind.ReturnStatement) (Syntax: 'x * x')
                         ReturnedValue: IBinaryOperatorExpression (BinaryOperationKind.IntegerMultiply) (OperationKind.BinaryOperatorExpression, Type: System.Int32) (Syntax: 'x * x')
diff --git a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IParameterReferenceExpression.cs b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IParameterReferenceExpression.cs
index 6de4f1159e9cc..d99fa6881ff4c 100644
--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IParameterReferenceExpression.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_IParameterReferenceExpression.cs
@@ -161,7 +161,7 @@ public void M(List<Customer> customers)
                   IArgument (ArgumentKind.Explicit, Matching Parameter: selector) (OperationKind.Argument) (Syntax: 'cust.Name')
                     IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Func<Customer, System.String>) (Syntax: 'cust.Name')
                       Conversion: CommonConversion (Exists: True, IsIdentity: True, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-                      Operand: ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null) (Syntax: 'cust.Name')
+                      Operand: IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null) (Syntax: 'cust.Name')
                           IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: 'cust.Name')
                             IReturnStatement (OperationKind.ReturnStatement) (Syntax: 'cust.Name')
                               ReturnedValue: IPropertyReferenceExpression: System.String Customer.Name { get; set; } (OperationKind.PropertyReferenceExpression, Type: System.String) (Syntax: 'cust.Name')
@@ -263,7 +263,7 @@ public void UsedParameterMethod1(Action a)
             string expectedOperationTree = @"
 IOperation:  (OperationKind.None) (Syntax: 'new Action( ... })')
   Children(1):
-      ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null) (Syntax: '() => ... }')
+      IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null) (Syntax: '() => ... }')
         IBlockStatement (2 statements) (OperationKind.BlockStatement) (Syntax: '{ ... }')
           IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'a();')
             Expression: IInvocationExpression (virtual void System.Action.Invoke()) (OperationKind.InvocationExpression, Type: System.Void) (Syntax: 'a()')
diff --git a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_InvalidExpression.cs b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_InvalidExpression.cs
index 4faf27423e007..c440d7c101de1 100644
--- a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_InvalidExpression.cs
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_InvalidExpression.cs
@@ -328,7 +328,7 @@ static void F()
 IVariableDeclarationStatement (1 variables) (OperationKind.VariableDeclarationStatement, IsInvalid) (Syntax: 'var x /*<bi ... *</bind>*/;')
   IVariableDeclaration: var x (OperationKind.VariableDeclaration) (Syntax: 'var x /*<bi ... *</bind>*/;')
     Initializer: IUnboundLambdaExpression (OperationKind.UnboundLambdaExpression, Type: null) (Syntax: '() => F()
-        ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null) (Syntax: '() => F()')
+        IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null) (Syntax: '() => F()')
           IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: 'F()')
             IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'F()')
               IInvocationExpression (static void Program.F()) (OperationKind.InvocationExpression, Type: System.Void) (Syntax: 'F()')')
@@ -362,7 +362,7 @@ static void F()
 }
 ";
             string expectedOperationTree = @"
-ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null, IsInvalid) (Syntax: '() => F()')
+IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null, IsInvalid) (Syntax: '() => F()')
   IBlockStatement (1 statements) (OperationKind.BlockStatement, IsInvalid) (Syntax: 'F()')
     IExpressionStatement (OperationKind.ExpressionStatement, IsInvalid) (Syntax: 'F()')
       Expression: IInvocationExpression (void Program.F()) (OperationKind.InvocationExpression, Type: System.Void, IsInvalid) (Syntax: 'F()')
diff --git a/src/Compilers/CSharp/Test/Symbol/Symbols/AnonymousTypesSemanticsTests.cs b/src/Compilers/CSharp/Test/Symbol/Symbols/AnonymousTypesSemanticsTests.cs
index 19cf329bccd3f..f4389ed4bce06 100644
--- a/src/Compilers/CSharp/Test/Symbol/Symbols/AnonymousTypesSemanticsTests.cs
+++ b/src/Compilers/CSharp/Test/Symbol/Symbols/AnonymousTypesSemanticsTests.cs
@@ -349,7 +349,7 @@ void Main()
             Instance Receiver: null
         Right: IConversionExpression (Explicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: D1) (Syntax: '(D1)(() => false)')
             Conversion: CommonConversion (Exists: True, IsIdentity: True, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-            Operand: ILambdaExpression (Signature: lambda expression) (OperationKind.LambdaExpression, Type: null) (Syntax: '() => false')
+            Operand: IAnonymousFunctionExpression (Symbol: lambda expression) (OperationKind.AnonymousFunctionExpression, Type: null) (Syntax: '() => false')
                 IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: 'false')
                   IReturnStatement (OperationKind.ReturnStatement) (Syntax: 'false')
                     ReturnedValue: ILiteralExpression (OperationKind.LiteralExpression, Type: System.Boolean, Constant: False) (Syntax: 'false')
diff --git a/src/Compilers/Core/Portable/Generated/Operations.xml.Generated.cs b/src/Compilers/Core/Portable/Generated/Operations.xml.Generated.cs
index 2db8a93319f5b..04af71a22adf2 100644
--- a/src/Compilers/Core/Portable/Generated/Operations.xml.Generated.cs
+++ b/src/Compilers/Core/Portable/Generated/Operations.xml.Generated.cs
@@ -2645,20 +2645,14 @@ public LazyLabelStatement(ILabelSymbol label, Lazy<IOperation> labeledStatement,
         protected override IOperation LabeledStatementImpl => _lazyLabeledStatement.Value;
     }
 
-    /// <summary>
-    /// Represents a lambda expression.
-    /// </summary>
-    internal abstract partial class BaseLambdaExpression : Operation, ILambdaExpression
+    internal abstract partial class BaseAnonymousFunctionExpression : Operation, IAnonymousFunctionExpression
     {
-        protected BaseLambdaExpression(IMethodSymbol signature, SemanticModel semanticModel, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) :
-                    base(OperationKind.LambdaExpression, semanticModel, syntax, type, constantValue)
+        protected BaseAnonymousFunctionExpression(IMethodSymbol symbol, SemanticModel semanticModel, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) :
+                    base(OperationKind.AnonymousFunctionExpression, semanticModel, syntax, type, constantValue)
         {
-            Signature = signature;
+            Symbol = symbol;
         }
-        /// <summary>
-        /// Signature of the lambda.
-        /// </summary>
-        public IMethodSymbol Signature { get; }
+        public IMethodSymbol Symbol { get; }
         protected abstract IBlockStatement BodyImpl { get; }
         public override IEnumerable<IOperation> Children
         {
@@ -2667,27 +2661,21 @@ public override IEnumerable<IOperation> Children
                 yield return Body;
             }
         }
-        /// <summary>
-        /// Body of the lambda.
-        /// </summary>
         public IBlockStatement Body => Operation.SetParentOperation(BodyImpl, this);
         public override void Accept(OperationVisitor visitor)
         {
-            visitor.VisitLambdaExpression(this);
+            visitor.VisitAnonymousFunctionExpression(this);
         }
         public override TResult Accept<TArgument, TResult>(OperationVisitor<TArgument, TResult> visitor, TArgument argument)
         {
-            return visitor.VisitLambdaExpression(this, argument);
+            return visitor.VisitAnonymousFunctionExpression(this, argument);
         }
     }
 
-    /// <summary>
-    /// Represents a lambda expression.
-    /// </summary>
-    internal sealed partial class LambdaExpression : BaseLambdaExpression, ILambdaExpression
+    internal sealed partial class AnonymousFunctionExpression : BaseAnonymousFunctionExpression, IAnonymousFunctionExpression
     {
-        public LambdaExpression(IMethodSymbol signature, IBlockStatement body, SemanticModel semanticModel, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) :
-            base(signature, semanticModel, syntax, type, constantValue)
+        public AnonymousFunctionExpression(IMethodSymbol symbol, IBlockStatement body, SemanticModel semanticModel, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) :
+            base(symbol, semanticModel, syntax, type, constantValue)
         {
             BodyImpl = body;
         }
@@ -2695,14 +2683,11 @@ internal sealed partial class LambdaExpression : BaseLambdaExpression, ILambdaEx
         protected override IBlockStatement BodyImpl { get; }
     }
 
-    /// <summary>
-    /// Represents a lambda expression.
-    /// </summary>
-    internal sealed partial class LazyLambdaExpression : BaseLambdaExpression, ILambdaExpression
+    internal sealed partial class LazyAnonymousFunctionExpression : BaseAnonymousFunctionExpression, IAnonymousFunctionExpression
     {
         private readonly Lazy<IBlockStatement> _lazyBody;
 
-        public LazyLambdaExpression(IMethodSymbol signature, Lazy<IBlockStatement> body, SemanticModel semanticModel, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) : base(signature, semanticModel, syntax, type, constantValue)
+        public LazyAnonymousFunctionExpression(IMethodSymbol symbol, Lazy<IBlockStatement> body, SemanticModel semanticModel, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) : base(symbol, semanticModel, syntax, type, constantValue)
         {
             _lazyBody = body ?? throw new System.ArgumentNullException(nameof(body));
         }
diff --git a/src/Compilers/Core/Portable/Operations/ILambdaExpression.cs b/src/Compilers/Core/Portable/Operations/IAnonymousFunctionExpression.cs
similarity index 67%
rename from src/Compilers/Core/Portable/Operations/ILambdaExpression.cs
rename to src/Compilers/Core/Portable/Operations/IAnonymousFunctionExpression.cs
index d39c83b44bca9..4eb29d38732e4 100644
--- a/src/Compilers/Core/Portable/Operations/ILambdaExpression.cs
+++ b/src/Compilers/Core/Portable/Operations/IAnonymousFunctionExpression.cs
@@ -5,20 +5,20 @@
 namespace Microsoft.CodeAnalysis.Semantics
 {
     /// <summary>
-    /// Represents a lambda expression.
+    /// Represents a anonymous function expression, such as a lambda or anonymous delegate.
     /// </summary>
     /// <remarks>
     /// This interface is reserved for implementation by its associated APIs. We reserve the right to
     /// change it in the future.
     /// </remarks>
-    public interface ILambdaExpression : IOperation
+    public interface IAnonymousFunctionExpression : IOperation
     {
         /// <summary>
-        /// Signature of the lambda.
+        /// Symbol of the anonymous function.
         /// </summary>
-        IMethodSymbol Signature { get; }
+        IMethodSymbol Symbol { get; }
         /// <summary>
-        /// Body of the lambda.
+        /// Body of the anonymous function.
         /// </summary>
         IBlockStatement Body { get; }
     }
diff --git a/src/Compilers/Core/Portable/Operations/OperationCloner.cs b/src/Compilers/Core/Portable/Operations/OperationCloner.cs
index 038de6c65fd1c..b69ac0dc06a99 100644
--- a/src/Compilers/Core/Portable/Operations/OperationCloner.cs
+++ b/src/Compilers/Core/Portable/Operations/OperationCloner.cs
@@ -294,9 +294,9 @@ public override IOperation VisitTypeOfExpression(ITypeOfExpression operation, ob
             return new TypeOfExpression(operation.TypeOperand, ((Operation)operation).SemanticModel, operation.Syntax, operation.Type, operation.ConstantValue);
         }
 
-        public override IOperation VisitLambdaExpression(ILambdaExpression operation, object argument)
+        public override IOperation VisitAnonymousFunctionExpression(IAnonymousFunctionExpression operation, object argument)
         {
-            return new LambdaExpression(operation.Signature, Visit(operation.Body), ((Operation)operation).SemanticModel, operation.Syntax, operation.Type, operation.ConstantValue);
+            return new AnonymousFunctionExpression(operation.Symbol, Visit(operation.Body), ((Operation)operation).SemanticModel, operation.Syntax, operation.Type, operation.ConstantValue);
         }
 
         public override IOperation VisitLiteralExpression(ILiteralExpression operation, object argument)
diff --git a/src/Compilers/Core/Portable/Operations/OperationKind.cs b/src/Compilers/Core/Portable/Operations/OperationKind.cs
index f0a17227330cd..fa875f4828f23 100644
--- a/src/Compilers/Core/Portable/Operations/OperationKind.cs
+++ b/src/Compilers/Core/Portable/Operations/OperationKind.cs
@@ -98,8 +98,8 @@ public enum OperationKind
         ConditionalChoiceExpression = 0x10f,
         /// <summary>Indicates an <see cref="INullCoalescingExpression"/>.</summary>
         NullCoalescingExpression = 0x110,
-        /// <summary>Indicates an <see cref="ILambdaExpression"/>.</summary>
-        LambdaExpression = 0x111,
+        /// <summary>Indicates an <see cref="IAnonymousFunctionExpression"/>.</summary>
+        AnonymousFunctionExpression = 0x111,
         /// <summary>Indicates an <see cref="IObjectCreationExpression"/>.</summary>
         ObjectCreationExpression = 0x112,
         /// <summary>Indicates an <see cref="ITypeParameterObjectCreationExpression"/>.</summary>
diff --git a/src/Compilers/Core/Portable/Operations/OperationVisitor.cs b/src/Compilers/Core/Portable/Operations/OperationVisitor.cs
index 56c1f3b4db093..712417ed90f9a 100644
--- a/src/Compilers/Core/Portable/Operations/OperationVisitor.cs
+++ b/src/Compilers/Core/Portable/Operations/OperationVisitor.cs
@@ -290,7 +290,7 @@ public virtual void VisitTypeOfExpression(ITypeOfExpression operation)
             DefaultVisit(operation);
         }
 
-        public virtual void VisitLambdaExpression(ILambdaExpression operation)
+        public virtual void VisitAnonymousFunctionExpression(IAnonymousFunctionExpression operation)
         {
             DefaultVisit(operation);
         }
@@ -760,7 +760,7 @@ public virtual TResult VisitTypeOfExpression(ITypeOfExpression operation, TArgum
             return DefaultVisit(operation, argument);
         }
 
-        public virtual TResult VisitLambdaExpression(ILambdaExpression operation, TArgument argument)
+        public virtual TResult VisitAnonymousFunctionExpression(IAnonymousFunctionExpression operation, TArgument argument)
         {
             return DefaultVisit(operation, argument);
         }
diff --git a/src/Compilers/Core/Portable/PublicAPI.Unshipped.txt b/src/Compilers/Core/Portable/PublicAPI.Unshipped.txt
index a9d2055d6d0f1..58259f22ea71f 100644
--- a/src/Compilers/Core/Portable/PublicAPI.Unshipped.txt
+++ b/src/Compilers/Core/Portable/PublicAPI.Unshipped.txt
@@ -91,7 +91,7 @@ Microsoft.CodeAnalysis.OperationKind.InvocationExpression = 259 -> Microsoft.Cod
 Microsoft.CodeAnalysis.OperationKind.IsPatternExpression = 517 -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.OperationKind.IsTypeExpression = 278 -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.OperationKind.LabelStatement = 7 -> Microsoft.CodeAnalysis.OperationKind
-Microsoft.CodeAnalysis.OperationKind.LambdaExpression = 273 -> Microsoft.CodeAnalysis.OperationKind
+Microsoft.CodeAnalysis.OperationKind.AnonymousFunctionExpression = 273 -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.OperationKind.LiteralExpression = 257 -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.OperationKind.LocalFunctionStatement = 49 -> Microsoft.CodeAnalysis.OperationKind
 Microsoft.CodeAnalysis.OperationKind.LocalReferenceExpression = 261 -> Microsoft.CodeAnalysis.OperationKind
@@ -485,9 +485,9 @@ Microsoft.CodeAnalysis.Semantics.IIsTypeExpression.Operand.get -> Microsoft.Code
 Microsoft.CodeAnalysis.Semantics.ILabelStatement
 Microsoft.CodeAnalysis.Semantics.ILabelStatement.Label.get -> Microsoft.CodeAnalysis.ILabelSymbol
 Microsoft.CodeAnalysis.Semantics.ILabelStatement.LabeledStatement.get -> Microsoft.CodeAnalysis.IOperation
-Microsoft.CodeAnalysis.Semantics.ILambdaExpression
-Microsoft.CodeAnalysis.Semantics.ILambdaExpression.Body.get -> Microsoft.CodeAnalysis.Semantics.IBlockStatement
-Microsoft.CodeAnalysis.Semantics.ILambdaExpression.Signature.get -> Microsoft.CodeAnalysis.IMethodSymbol
+Microsoft.CodeAnalysis.Semantics.IAnonymousFunctionExpression
+Microsoft.CodeAnalysis.Semantics.IAnonymousFunctionExpression.Body.get -> Microsoft.CodeAnalysis.Semantics.IBlockStatement
+Microsoft.CodeAnalysis.Semantics.IAnonymousFunctionExpression.Symbol.get -> Microsoft.CodeAnalysis.IMethodSymbol
 Microsoft.CodeAnalysis.Semantics.ILiteralExpression
 Microsoft.CodeAnalysis.Semantics.ILiteralExpression.Text.get -> string
 Microsoft.CodeAnalysis.Semantics.ILocalFunctionStatement
@@ -819,7 +819,7 @@ virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitInvocationExpress
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitIsPatternExpression(Microsoft.CodeAnalysis.Semantics.IIsPatternExpression operation) -> void
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitIsTypeExpression(Microsoft.CodeAnalysis.Semantics.IIsTypeExpression operation) -> void
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitLabelStatement(Microsoft.CodeAnalysis.Semantics.ILabelStatement operation) -> void
-virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitLambdaExpression(Microsoft.CodeAnalysis.Semantics.ILambdaExpression operation) -> void
+virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitAnonymousFunctionExpression(Microsoft.CodeAnalysis.Semantics.IAnonymousFunctionExpression operation) -> void
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitLiteralExpression(Microsoft.CodeAnalysis.Semantics.ILiteralExpression operation) -> void
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitLocalFunctionStatement(Microsoft.CodeAnalysis.Semantics.ILocalFunctionStatement operation) -> void
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor.VisitLocalReferenceExpression(Microsoft.CodeAnalysis.Semantics.ILocalReferenceExpression operation) -> void
@@ -909,7 +909,7 @@ virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.Vi
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitIsPatternExpression(Microsoft.CodeAnalysis.Semantics.IIsPatternExpression operation, TArgument argument) -> TResult
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitIsTypeExpression(Microsoft.CodeAnalysis.Semantics.IIsTypeExpression operation, TArgument argument) -> TResult
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitLabelStatement(Microsoft.CodeAnalysis.Semantics.ILabelStatement operation, TArgument argument) -> TResult
-virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitLambdaExpression(Microsoft.CodeAnalysis.Semantics.ILambdaExpression operation, TArgument argument) -> TResult
+virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitAnonymousFunctionExpression(Microsoft.CodeAnalysis.Semantics.IAnonymousFunctionExpression operation, TArgument argument) -> TResult
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitLiteralExpression(Microsoft.CodeAnalysis.Semantics.ILiteralExpression operation, TArgument argument) -> TResult
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitLocalFunctionStatement(Microsoft.CodeAnalysis.Semantics.ILocalFunctionStatement operation, TArgument argument) -> TResult
 virtual Microsoft.CodeAnalysis.Semantics.OperationVisitor<TArgument, TResult>.VisitLocalReferenceExpression(Microsoft.CodeAnalysis.Semantics.ILocalReferenceExpression operation, TArgument argument) -> TResult
diff --git a/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb b/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
index 8eed84d14b050..40e5db347d2f9 100644
--- a/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
+++ b/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
@@ -331,13 +331,13 @@ Namespace Microsoft.CodeAnalysis.Semantics
             Return New LazyNameOfExpression(argument, _semanticModel, syntax, type, constantValue)
         End Function
 
-        Private Function CreateBoundLambdaOperation(boundLambda As BoundLambda) As ILambdaExpression
-            Dim signature As IMethodSymbol = boundLambda.LambdaSymbol
+        Private Function CreateBoundLambdaOperation(boundLambda As BoundLambda) As IAnonymousFunctionExpression
+            Dim symbol As IMethodSymbol = boundLambda.LambdaSymbol
             Dim body As Lazy(Of IBlockStatement) = New Lazy(Of IBlockStatement)(Function() DirectCast(Create(boundLambda.Body), IBlockStatement))
             Dim syntax As SyntaxNode = boundLambda.Syntax
             Dim type As ITypeSymbol = boundLambda.Type
             Dim constantValue As [Optional](Of Object) = ConvertToOptional(boundLambda.ConstantValueOpt)
-            Return New LazyLambdaExpression(signature, body, _semanticModel, syntax, type, constantValue)
+            Return New LazyAnonymousFunctionExpression(symbol, body, _semanticModel, syntax, type, constantValue)
         End Function
 
         Private Function CreateBoundCallOperation(boundCall As BoundCall) As IInvocationExpression
diff --git a/src/Compilers/VisualBasic/Test/Semantic/Binding/BindingObjectInitializerTests.vb b/src/Compilers/VisualBasic/Test/Semantic/Binding/BindingObjectInitializerTests.vb
index 29d1540ef04df..c689c3ebc2bd2 100644
--- a/src/Compilers/VisualBasic/Test/Semantic/Binding/BindingObjectInitializerTests.vb
+++ b/src/Compilers/VisualBasic/Test/Semantic/Binding/BindingObjectInitializerTests.vb
@@ -1125,7 +1125,7 @@ IObjectCreationExpression (Constructor: Sub C1..ctor()) (OperationKind.ObjectCre
                 Instance Receiver: IOperation:  (OperationKind.None) (Syntax: 'New C1 With ... d Function}')
             Right: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Func(Of System.Int32)) (Syntax: 'Function()  ... nd Function')
                 Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-                Operand: ILambdaExpression (Signature: Function () As System.Int32) (OperationKind.LambdaExpression, Type: null) (Syntax: 'Function()  ... nd Function')
+                Operand: IAnonymousFunctionExpression (Symbol: Function () As System.Int32) (OperationKind.AnonymousFunctionExpression, Type: null) (Syntax: 'Function()  ... nd Function')
                     IBlockStatement (3 statements, 1 locals) (OperationKind.BlockStatement) (Syntax: 'Function()  ... nd Function')
                       Locals: Local_1: <anonymous local> As System.Int32
                       IReturnStatement (OperationKind.ReturnStatement) (Syntax: 'Return .Field')
@@ -1395,7 +1395,7 @@ IObjectCreationExpression (Constructor: Sub C2..ctor()) (OperationKind.ObjectCre
                 Instance Receiver: IOperation:  (OperationKind.None) (Syntax: 'As New C2 W ... d Function}')
             Right: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Func(Of System.Object)) (Syntax: 'Function()' ... nd Function')
                 Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-                Operand: ILambdaExpression (Signature: Function () As System.Object) (OperationKind.LambdaExpression, Type: null) (Syntax: 'Function()' ... nd Function')
+                Operand: IAnonymousFunctionExpression (Symbol: Function () As System.Object) (OperationKind.AnonymousFunctionExpression, Type: null) (Syntax: 'Function()' ... nd Function')
                     IBlockStatement (3 statements, 1 locals) (OperationKind.BlockStatement) (Syntax: 'Function()' ... nd Function')
                       Locals: Local_1: <anonymous local> As System.Object
                       IReturnStatement (OperationKind.ReturnStatement) (Syntax: 'Return .Field')
@@ -1412,7 +1412,7 @@ IObjectCreationExpression (Constructor: Sub C2..ctor()) (OperationKind.ObjectCre
                 Instance Receiver: IOperation:  (OperationKind.None) (Syntax: 'As New C2 W ... d Function}')
             Right: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Func(Of System.Object)) (Syntax: 'Function() ... nd Function')
                 Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-                Operand: ILambdaExpression (Signature: Function () As System.Object) (OperationKind.LambdaExpression, Type: null) (Syntax: 'Function() ... nd Function')
+                Operand: IAnonymousFunctionExpression (Symbol: Function () As System.Object) (OperationKind.AnonymousFunctionExpression, Type: null) (Syntax: 'Function() ... nd Function')
                     IBlockStatement (3 statements, 1 locals) (OperationKind.BlockStatement) (Syntax: 'Function() ... nd Function')
                       Locals: Local_1: <anonymous local> As System.Object
                       IReturnStatement (OperationKind.ReturnStatement) (Syntax: 'Return .Field')
diff --git a/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_IConversionExpression.vb b/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_IConversionExpression.vb
index 3a23439ffd2e0..dfc2799ce813e 100644
--- a/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_IConversionExpression.vb
+++ b/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_IConversionExpression.vb
@@ -762,7 +762,7 @@ IVariableDeclarationStatement (1 declarations) (OperationKind.VariableDeclaratio
     Variables: Local_1: a As System.Action(Of System.Int32)
     Initializer: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Action(Of System.Int32)) (Syntax: 'Sub(i As In ... End Sub')
         Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-        Operand: ILambdaExpression (Signature: Sub (i As System.Int32)) (OperationKind.LambdaExpression, Type: null) (Syntax: 'Sub(i As In ... End Sub')
+        Operand: IAnonymousFunctionExpression (Symbol: Sub (i As System.Int32)) (OperationKind.AnonymousFunctionExpression, Type: null) (Syntax: 'Sub(i As In ... End Sub')
             IBlockStatement (2 statements) (OperationKind.BlockStatement) (Syntax: 'Sub(i As In ... End Sub')
               ILabelStatement (Label: exit) (OperationKind.LabelStatement) (Syntax: 'End Sub')
                 LabeledStatement: null
@@ -795,7 +795,7 @@ IVariableDeclarationStatement (1 declarations) (OperationKind.VariableDeclaratio
     Variables: Local_1: a As System.Action(Of System.Int32)
     Initializer: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Action(Of System.Int32)) (Syntax: 'Sub()'BIND: ... End Sub')
         Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-        Operand: ILambdaExpression (Signature: Sub ()) (OperationKind.LambdaExpression, Type: null) (Syntax: 'Sub()'BIND: ... End Sub')
+        Operand: IAnonymousFunctionExpression (Symbol: Sub ()) (OperationKind.AnonymousFunctionExpression, Type: null) (Syntax: 'Sub()'BIND: ... End Sub')
             IBlockStatement (2 statements) (OperationKind.BlockStatement) (Syntax: 'Sub()'BIND: ... End Sub')
               ILabelStatement (Label: exit) (OperationKind.LabelStatement) (Syntax: 'End Sub')
                 LabeledStatement: null
@@ -828,7 +828,7 @@ IVariableDeclarationStatement (1 declarations) (OperationKind.VariableDeclaratio
     Variables: Local_1: a As System.Action
     Initializer: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Action, IsInvalid) (Syntax: 'Sub(i As In ... End Sub')
         Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-        Operand: ILambdaExpression (Signature: Sub (i As System.Int32)) (OperationKind.LambdaExpression, Type: null, IsInvalid) (Syntax: 'Sub(i As In ... End Sub')
+        Operand: IAnonymousFunctionExpression (Symbol: Sub (i As System.Int32)) (OperationKind.AnonymousFunctionExpression, Type: null, IsInvalid) (Syntax: 'Sub(i As In ... End Sub')
             IBlockStatement (2 statements) (OperationKind.BlockStatement, IsInvalid) (Syntax: 'Sub(i As In ... End Sub')
               ILabelStatement (Label: exit) (OperationKind.LabelStatement, IsInvalid) (Syntax: 'End Sub')
                 LabeledStatement: null
@@ -866,7 +866,7 @@ IVariableDeclarationStatement (1 declarations) (OperationKind.VariableDeclaratio
     Variables: Local_1: a As System.Func(Of System.Int64)
     Initializer: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Func(Of System.Int64)) (Syntax: 'Function()  ... nd Function')
         Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-        Operand: ILambdaExpression (Signature: Function () As System.Int32) (OperationKind.LambdaExpression, Type: null) (Syntax: 'Function()  ... nd Function')
+        Operand: IAnonymousFunctionExpression (Symbol: Function () As System.Int32) (OperationKind.AnonymousFunctionExpression, Type: null) (Syntax: 'Function()  ... nd Function')
             IBlockStatement (3 statements, 1 locals) (OperationKind.BlockStatement) (Syntax: 'Function()  ... nd Function')
               Locals: Local_1: <anonymous local> As System.Int32
               IReturnStatement (OperationKind.ReturnStatement) (Syntax: 'Return 1')
@@ -903,7 +903,7 @@ IVariableDeclarationStatement (1 declarations) (OperationKind.VariableDeclaratio
     Variables: Local_1: a As System.Action(Of System.Int32)
     Initializer: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Action(Of System.Int32)) (Syntax: 'Function()  ... nd Function')
         Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-        Operand: ILambdaExpression (Signature: Function () As System.Int32) (OperationKind.LambdaExpression, Type: null) (Syntax: 'Function()  ... nd Function')
+        Operand: IAnonymousFunctionExpression (Symbol: Function () As System.Int32) (OperationKind.AnonymousFunctionExpression, Type: null) (Syntax: 'Function()  ... nd Function')
             IBlockStatement (3 statements, 1 locals) (OperationKind.BlockStatement) (Syntax: 'Function()  ... nd Function')
               Locals: Local_1: <anonymous local> As System.Int32
               IReturnStatement (OperationKind.ReturnStatement) (Syntax: 'Return 1')
@@ -939,7 +939,7 @@ IVariableDeclarationStatement (1 declarations) (OperationKind.VariableDeclaratio
     Variables: Local_1: a As System.Func(Of System.Int32)
     Initializer: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Func(Of System.Int32), IsInvalid) (Syntax: 'Sub()'BIND: ... End Sub')
         Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-        Operand: ILambdaExpression (Signature: Sub ()) (OperationKind.LambdaExpression, Type: null, IsInvalid) (Syntax: 'Sub()'BIND: ... End Sub')
+        Operand: IAnonymousFunctionExpression (Symbol: Sub ()) (OperationKind.AnonymousFunctionExpression, Type: null, IsInvalid) (Syntax: 'Sub()'BIND: ... End Sub')
             IBlockStatement (2 statements) (OperationKind.BlockStatement, IsInvalid) (Syntax: 'Sub()'BIND: ... End Sub')
               ILabelStatement (Label: exit) (OperationKind.LabelStatement, IsInvalid) (Syntax: 'End Sub')
                 LabeledStatement: null
@@ -2097,7 +2097,7 @@ IVariableDeclarationStatement (1 declarations) (OperationKind.VariableDeclaratio
     Variables: Local_1: expr As System.Linq.Expressions.Expression(Of System.Func(Of System.Int32, System.Boolean))
     Initializer: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Linq.Expressions.Expression(Of System.Func(Of System.Int32, System.Boolean))) (Syntax: 'Function(num) num < 5')
         Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-        Operand: ILambdaExpression (Signature: Function (num As System.Int32) As System.Boolean) (OperationKind.LambdaExpression, Type: null) (Syntax: 'Function(num) num < 5')
+        Operand: IAnonymousFunctionExpression (Symbol: Function (num As System.Int32) As System.Boolean) (OperationKind.AnonymousFunctionExpression, Type: null) (Syntax: 'Function(num) num < 5')
             IBlockStatement (3 statements, 1 locals) (OperationKind.BlockStatement) (Syntax: 'Function(num) num < 5')
               Locals: Local_1: <anonymous local> As System.Boolean
               IReturnStatement (OperationKind.ReturnStatement) (Syntax: 'num < 5')
@@ -2137,7 +2137,7 @@ IVariableDeclarationStatement (1 declarations) (OperationKind.VariableDeclaratio
     Variables: Local_1: expr As System.Linq.Expressions.Expression(Of System.Func(Of System.Int32, System.Boolean))
     Initializer: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Linq.Expressions.Expression(Of System.Func(Of System.Int32, System.Boolean)), IsInvalid) (Syntax: 'Function(num) num')
         Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-        Operand: ILambdaExpression (Signature: Function (num As System.Int32) As System.Boolean) (OperationKind.LambdaExpression, Type: null, IsInvalid) (Syntax: 'Function(num) num')
+        Operand: IAnonymousFunctionExpression (Symbol: Function (num As System.Int32) As System.Boolean) (OperationKind.AnonymousFunctionExpression, Type: null, IsInvalid) (Syntax: 'Function(num) num')
             IBlockStatement (3 statements, 1 locals) (OperationKind.BlockStatement, IsInvalid) (Syntax: 'Function(num) num')
               Locals: Local_1: <anonymous local> As System.Boolean
               IReturnStatement (OperationKind.ReturnStatement, IsInvalid) (Syntax: 'num')
diff --git a/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_IParameterReferenceExpression.vb b/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_IParameterReferenceExpression.vb
index 745f3c679c0b9..b3517fcf46a36 100644
--- a/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_IParameterReferenceExpression.vb
+++ b/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_IParameterReferenceExpression.vb
@@ -380,7 +380,7 @@ End Class]]>.Value
             Dim expectedOperationTree = <![CDATA[
 IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.EventHandler) (Syntax: 'New EventHa ... nction() x)')
   Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-  Operand: ILambdaExpression (Signature: Function () As System.Object) (OperationKind.LambdaExpression, Type: null) (Syntax: 'Function() x')
+  Operand: IAnonymousFunctionExpression (Symbol: Function () As System.Object) (OperationKind.AnonymousFunctionExpression, Type: null) (Syntax: 'Function() x')
       IBlockStatement (3 statements, 1 locals) (OperationKind.BlockStatement) (Syntax: 'Function() x')
         Locals: Local_1: <anonymous local> As System.Object
         IReturnStatement (OperationKind.ReturnStatement) (Syntax: 'x')
diff --git a/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_InvalidExpression.vb b/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_InvalidExpression.vb
index d777d2ff1589c..5ce2555eea031 100644
--- a/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_InvalidExpression.vb
+++ b/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_InvalidExpression.vb
@@ -278,7 +278,7 @@ End Class]]>.Value
 Dim expectedOperationTree = <![CDATA[
 IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: Function <generated method>() As ?, IsInvalid) (Syntax: 'Function() F()')
   Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-  Operand: ILambdaExpression (Signature: Function () As ?) (OperationKind.LambdaExpression, Type: null, IsInvalid) (Syntax: 'Function() F()')
+  Operand: IAnonymousFunctionExpression (Symbol: Function () As ?) (OperationKind.AnonymousFunctionExpression, Type: null, IsInvalid) (Syntax: 'Function() F()')
       IBlockStatement (3 statements, 1 locals) (OperationKind.BlockStatement, IsInvalid) (Syntax: 'Function() F()')
         Locals: Local_1: <anonymous local> As ?
         IReturnStatement (OperationKind.ReturnStatement, IsInvalid) (Syntax: 'F()')
diff --git a/src/Compilers/VisualBasic/Test/Semantic/Semantics/AnonymousTypesTests.vb b/src/Compilers/VisualBasic/Test/Semantic/Semantics/AnonymousTypesTests.vb
index d08e07a0fe626..76c2d0927d791 100644
--- a/src/Compilers/VisualBasic/Test/Semantic/Semantics/AnonymousTypesTests.vb
+++ b/src/Compilers/VisualBasic/Test/Semantic/Semantics/AnonymousTypesTests.vb
@@ -812,7 +812,7 @@ Module Program
     End Sub
 End Module]]>.Value
 
-            ' The IOperation tree for this test seems to have an unexpected ILocalReferenceExpression within ILambdaExpression.
+            ' The IOperation tree for this test seems to have an unexpected ILocalReferenceExpression within IAnonymousFunctionExpression.
             ' See https://github.com/dotnet/roslyn/issues/20357.
             Dim expectedOperationTree = <![CDATA[
 IAnonymousObjectCreationExpression (OperationKind.AnonymousObjectCreationExpression, Type: <anonymous type: Key x As System.String, Key a As System.String>, IsInvalid) (Syntax: 'New With {' ... ).Invoke()}')
@@ -827,7 +827,7 @@ IAnonymousObjectCreationExpression (OperationKind.AnonymousObjectCreationExpress
         Right: IInvocationExpression (virtual Function System.Func(Of System.String).Invoke() As System.String) (OperationKind.InvocationExpression, Type: System.String, IsInvalid) (Syntax: 'DirectCast( ... )).Invoke()')
             Instance Receiver: IConversionExpression (Explicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Func(Of System.String), IsInvalid) (Syntax: 'DirectCast( ... Of String))')
                 Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-                Operand: ILambdaExpression (Signature: Function () As System.String) (OperationKind.LambdaExpression, Type: null, IsInvalid) (Syntax: 'Function()  ... nd Function')
+                Operand: IAnonymousFunctionExpression (Symbol: Function () As System.String) (OperationKind.AnonymousFunctionExpression, Type: null, IsInvalid) (Syntax: 'Function()  ... nd Function')
                     IBlockStatement (3 statements, 1 locals) (OperationKind.BlockStatement, IsInvalid) (Syntax: 'Function()  ... nd Function')
                       Locals: Local_1: <anonymous local> As System.String
                       IReturnStatement (OperationKind.ReturnStatement, IsInvalid) (Syntax: 'Return .x.ToString()')
@@ -864,7 +864,7 @@ Module Program
     End Sub
 End Module]]>.Value
 
-            ' The IOperation tree for this test seems to have an unexpected ILocalReferenceExpression within ILambdaExpression.
+            ' The IOperation tree for this test seems to have an unexpected ILocalReferenceExpression within IAnonymousFunctionExpression.
             ' See https://github.com/dotnet/roslyn/issues/20357.
             Dim expectedOperationTree = <![CDATA[
 IAnonymousObjectCreationExpression (OperationKind.AnonymousObjectCreationExpression, Type: <anonymous type: Key a As System.String>, IsInvalid) (Syntax: 'New With {' ... ).Invoke()}')
@@ -875,7 +875,7 @@ IAnonymousObjectCreationExpression (OperationKind.AnonymousObjectCreationExpress
         Right: IInvocationExpression (virtual Function System.Func(Of System.String).Invoke() As System.String) (OperationKind.InvocationExpression, Type: System.String, IsInvalid) (Syntax: 'DirectCast( ... )).Invoke()')
             Instance Receiver: IConversionExpression (Explicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Func(Of System.String), IsInvalid) (Syntax: 'DirectCast( ... Of String))')
                 Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-                Operand: ILambdaExpression (Signature: Function () As System.String) (OperationKind.LambdaExpression, Type: null, IsInvalid) (Syntax: 'Function()  ... nd Function')
+                Operand: IAnonymousFunctionExpression (Symbol: Function () As System.String) (OperationKind.AnonymousFunctionExpression, Type: null, IsInvalid) (Syntax: 'Function()  ... nd Function')
                     IBlockStatement (3 statements, 1 locals) (OperationKind.BlockStatement, IsInvalid) (Syntax: 'Function()  ... nd Function')
                       Locals: Local_1: <anonymous local> As System.String
                       IReturnStatement (OperationKind.ReturnStatement, IsInvalid) (Syntax: 'Return .a.ToString()')
@@ -918,7 +918,7 @@ Module Program
     End Sub
 End Module]]>.Value
 
-            ' The IOperation tree for this test seems to have an unexpected ILocalReferenceExpression within ILambdaExpression.
+            ' The IOperation tree for this test seems to have an unexpected ILocalReferenceExpression within IAnonymousFunctionExpression.
             ' See https://github.com/dotnet/roslyn/issues/20357.
             Dim expectedOperationTree = <![CDATA[
 IAnonymousObjectCreationExpression (OperationKind.AnonymousObjectCreationExpression, Type: <anonymous type: Key a As System.String>, IsInvalid) (Syntax: 'New With {' ... ).Invoke()}')
@@ -929,7 +929,7 @@ IAnonymousObjectCreationExpression (OperationKind.AnonymousObjectCreationExpress
         Right: IInvocationExpression (virtual Function System.Func(Of System.String).Invoke() As System.String) (OperationKind.InvocationExpression, Type: System.String, IsInvalid) (Syntax: 'DirectCast( ... )).Invoke()')
             Instance Receiver: IConversionExpression (Explicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Func(Of System.String), IsInvalid) (Syntax: 'DirectCast( ... Of String))')
                 Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-                Operand: ILambdaExpression (Signature: Function () As System.String) (OperationKind.LambdaExpression, Type: null, IsInvalid) (Syntax: 'Function()  ... nd Function')
+                Operand: IAnonymousFunctionExpression (Symbol: Function () As System.String) (OperationKind.AnonymousFunctionExpression, Type: null, IsInvalid) (Syntax: 'Function()  ... nd Function')
                     IBlockStatement (3 statements, 1 locals) (OperationKind.BlockStatement, IsInvalid) (Syntax: 'Function()  ... nd Function')
                       Locals: Local_1: <anonymous local> As System.String
                       IReturnStatement (OperationKind.ReturnStatement, IsInvalid) (Syntax: 'Return .x.ToString()')
@@ -974,7 +974,7 @@ Module Program
     End Sub
 End Module]]>.Value
 
-            ' The IOperation tree for this test seems to have an unexpected ILocalReferenceExpression within ILambdaExpression.
+            ' The IOperation tree for this test seems to have an unexpected ILocalReferenceExpression within IAnonymousFunctionExpression.
             ' See https://github.com/dotnet/roslyn/issues/20357.
             Dim expectedOperationTree = <![CDATA[
 IAnonymousObjectCreationExpression (OperationKind.AnonymousObjectCreationExpression, Type: <anonymous type: Key a As System.String>, IsInvalid) (Syntax: 'New With {' ... ).Invoke()}')
@@ -985,14 +985,14 @@ IAnonymousObjectCreationExpression (OperationKind.AnonymousObjectCreationExpress
         Right: IInvocationExpression (virtual Function System.Func(Of System.String).Invoke() As System.String) (OperationKind.InvocationExpression, Type: System.String, IsInvalid) (Syntax: 'DirectCast( ... )).Invoke()')
             Instance Receiver: IConversionExpression (Explicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Func(Of System.String), IsInvalid) (Syntax: 'DirectCast( ... Of String))')
                 Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-                Operand: ILambdaExpression (Signature: Function () As System.String) (OperationKind.LambdaExpression, Type: null, IsInvalid) (Syntax: 'Function()  ... nd Function')
+                Operand: IAnonymousFunctionExpression (Symbol: Function () As System.String) (OperationKind.AnonymousFunctionExpression, Type: null, IsInvalid) (Syntax: 'Function()  ... nd Function')
                     IBlockStatement (3 statements, 1 locals) (OperationKind.BlockStatement, IsInvalid) (Syntax: 'Function()  ... nd Function')
                       Locals: Local_1: <anonymous local> As System.String
                       IReturnStatement (OperationKind.ReturnStatement, IsInvalid) (Syntax: 'Return Dire ... )).Invoke()')
                         ReturnedValue: IInvocationExpression (virtual Function System.Func(Of System.String).Invoke() As System.String) (OperationKind.InvocationExpression, Type: System.String, IsInvalid) (Syntax: 'DirectCast( ... )).Invoke()')
                             Instance Receiver: IConversionExpression (Explicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: System.Func(Of System.String), IsInvalid) (Syntax: 'DirectCast( ... Of String))')
                                 Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-                                Operand: ILambdaExpression (Signature: Function () As System.String) (OperationKind.LambdaExpression, Type: null, IsInvalid) (Syntax: 'Function()  ... nd Function')
+                                Operand: IAnonymousFunctionExpression (Symbol: Function () As System.String) (OperationKind.AnonymousFunctionExpression, Type: null, IsInvalid) (Syntax: 'Function()  ... nd Function')
                                     IBlockStatement (3 statements, 1 locals) (OperationKind.BlockStatement, IsInvalid) (Syntax: 'Function()  ... nd Function')
                                       Locals: Local_1: <anonymous local> As System.String
                                       IReturnStatement (OperationKind.ReturnStatement, IsInvalid) (Syntax: 'Return .x.ToString()')
diff --git a/src/Compilers/VisualBasic/Test/Semantic/Semantics/SelectCaseTests.vb b/src/Compilers/VisualBasic/Test/Semantic/Semantics/SelectCaseTests.vb
index c59efb3e28eb0..c557d7516b7c6 100644
--- a/src/Compilers/VisualBasic/Test/Semantic/Semantics/SelectCaseTests.vb
+++ b/src/Compilers/VisualBasic/Test/Semantic/Semantics/SelectCaseTests.vb
@@ -592,7 +592,7 @@ ISwitchStatement (2 cases) (OperationKind.SwitchStatement) (Syntax: 'Select Case
                     Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
                     Operand: IConversionExpression (Implicit, TryCast: False, Unchecked) (OperationKind.ConversionExpression, Type: Function <generated method>() As System.Int32) (Syntax: 'Function() 5')
                         Conversion: CommonConversion (Exists: False, IsIdentity: False, IsNumeric: False, IsReference: False, IsUserDefined: False) (MethodSymbol: null)
-                        Operand: ILambdaExpression (Signature: Function () As System.Int32) (OperationKind.LambdaExpression, Type: null) (Syntax: 'Function() 5')
+                        Operand: IAnonymousFunctionExpression (Symbol: Function () As System.Int32) (OperationKind.AnonymousFunctionExpression, Type: null) (Syntax: 'Function() 5')
                             IBlockStatement (3 statements, 1 locals) (OperationKind.BlockStatement) (Syntax: 'Function() 5')
                               Locals: Local_1: <anonymous local> As System.Int32
                               IReturnStatement (OperationKind.ReturnStatement) (Syntax: '5')
diff --git a/src/Test/Utilities/Portable/Compilation/OperationTreeVerifier.cs b/src/Test/Utilities/Portable/Compilation/OperationTreeVerifier.cs
index 25ba77ef569b7..7637f8195a321 100644
--- a/src/Test/Utilities/Portable/Compilation/OperationTreeVerifier.cs
+++ b/src/Test/Utilities/Portable/Compilation/OperationTreeVerifier.cs
@@ -906,15 +906,15 @@ public override void VisitTypeOfExpression(ITypeOfExpression operation)
             LogTypeOperationExpressionCommon(operation);
         }
 
-        public override void VisitLambdaExpression(ILambdaExpression operation)
+        public override void VisitAnonymousFunctionExpression(IAnonymousFunctionExpression operation)
         {
-            LogString(nameof(ILambdaExpression));
+            LogString(nameof(IAnonymousFunctionExpression));
 
-            LogSymbol(operation.Signature, header: " (Signature");
+            LogSymbol(operation.Symbol, header: " (Symbol");
             LogString(")");
             LogCommonPropertiesAndNewLine(operation);
 
-            base.VisitLambdaExpression(operation);
+            base.VisitAnonymousFunctionExpression(operation);
         }
 
         public override void VisitLiteralExpression(ILiteralExpression operation)
diff --git a/src/Test/Utilities/Portable/Compilation/TestOperationWalker.cs b/src/Test/Utilities/Portable/Compilation/TestOperationWalker.cs
index ae9cdd4978e9c..cbcf856a56e67 100644
--- a/src/Test/Utilities/Portable/Compilation/TestOperationWalker.cs
+++ b/src/Test/Utilities/Portable/Compilation/TestOperationWalker.cs
@@ -398,11 +398,11 @@ public override void VisitTypeOfExpression(ITypeOfExpression operation)
             base.VisitTypeOfExpression(operation);
         }
 
-        public override void VisitLambdaExpression(ILambdaExpression operation)
+        public override void VisitAnonymousFunctionExpression(IAnonymousFunctionExpression operation)
         {
-            var signature = operation.Signature;
+            var signature = operation.Symbol;
 
-            base.VisitLambdaExpression(operation);
+            base.VisitAnonymousFunctionExpression(operation);
         }
 
         public override void VisitLocalFunctionStatement(ILocalFunctionStatement operation)
diff --git a/src/Test/Utilities/Portable/Diagnostics/OperationTestAnalyzer.cs b/src/Test/Utilities/Portable/Diagnostics/OperationTestAnalyzer.cs
index dc3600b9ad6f3..de1e67a687ae0 100644
--- a/src/Test/Utilities/Portable/Diagnostics/OperationTestAnalyzer.cs
+++ b/src/Test/Utilities/Portable/Diagnostics/OperationTestAnalyzer.cs
@@ -1332,7 +1332,7 @@ public sealed override void Initialize(AnalysisContext context)
             context.RegisterOperationAction(
                  (operationContext) =>
                  {
-                     var lambdaExpression = (ILambdaExpression)operationContext.Operation;
+                     var lambdaExpression = (IAnonymousFunctionExpression)operationContext.Operation;
                      operationContext.ReportDiagnostic(Diagnostic.Create(LambdaExpressionDescriptor, operationContext.Operation.Syntax.GetLocation()));
                      var block = lambdaExpression.Body;
                      // TODO: Can this possibly be null? Remove check if not.
@@ -1358,7 +1358,7 @@ public sealed override void Initialize(AnalysisContext context)
                          operationContext.ReportDiagnostic(Diagnostic.Create(NoneOperationInLambdaExpressionDescriptor, operationContext.Operation.Syntax.GetLocation()));
                      }
                  },
-                 OperationKind.LambdaExpression);
+                 OperationKind.AnonymousFunctionExpression);
         }
     }
 

From d08809177c706f7db9e025811a85c15a81ef42b2 Mon Sep 17 00:00:00 2001
From: CyrusNajmabadi <cyrusn@microsoft.com>
Date: Sat, 12 Aug 2017 16:23:11 -0700
Subject: [PATCH 42/77] Initial work to offer to convert text in a doc comment
 to a real tag.

---
 ...ntTextWithSeeTagCodeRefactoringProvider.cs | 179 ++++++++++++++++++
 .../Portable/FeaturesResources.Designer.cs    |   9 +
 .../Core/Portable/FeaturesResources.resx      |   3 +
 3 files changed, 191 insertions(+)
 create mode 100644 src/Features/CSharp/Portable/ReplaceDocCommentTextWithSeeElement/ReplaceDocCommentTextWithSeeTagCodeRefactoringProvider.cs

diff --git a/src/Features/CSharp/Portable/ReplaceDocCommentTextWithSeeElement/ReplaceDocCommentTextWithSeeTagCodeRefactoringProvider.cs b/src/Features/CSharp/Portable/ReplaceDocCommentTextWithSeeElement/ReplaceDocCommentTextWithSeeTagCodeRefactoringProvider.cs
new file mode 100644
index 0000000000000..3e7eafe2f2527
--- /dev/null
+++ b/src/Features/CSharp/Portable/ReplaceDocCommentTextWithSeeElement/ReplaceDocCommentTextWithSeeTagCodeRefactoringProvider.cs
@@ -0,0 +1,179 @@
+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Composition;
+using System.Text;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.CodeAnalysis.CodeActions;
+using Microsoft.CodeAnalysis.CodeRefactorings;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Shared.Extensions;
+using Microsoft.CodeAnalysis.Text;
+
+namespace Microsoft.CodeAnalysis.CSharp.ReplaceDocCommentTextWithSeeElement
+{
+    [ExportCodeRefactoringProvider(LanguageNames.CSharp), Shared]
+    internal class ReplaceDocCommentTextWithSeeTagCodeRefactoringProvider : CodeRefactoringProvider
+    {
+        public override async Task ComputeRefactoringsAsync(CodeRefactoringContext context)
+        {
+            var document = context.Document;
+            var span = context.Span;
+            var cancellationToken = context.CancellationToken;
+
+            var root = await document.GetSyntaxRootAsync(cancellationToken).ConfigureAwait(false);
+            var token = root.FindToken(span.Start, findInsideTrivia: true);
+
+            if (token.Kind() != SyntaxKind.XmlTextLiteralToken &&
+                token.Kind() != SyntaxKind.XmlTextLiteralNewLineToken)
+            {
+                return;
+            }
+
+            if (!token.FullSpan.Contains(span))
+            {
+                return;
+            }
+
+            var sourceText = await document.GetTextAsync(cancellationToken).ConfigureAwait(false);
+
+            var expandedSpan = ExpandSpan(sourceText, span, includeDots: false);
+            var text = sourceText.ToString(expandedSpan);
+
+            if (SyntaxFacts.GetKeywordKind(text) != SyntaxKind.None ||
+                SyntaxFacts.GetContextualKeywordKind(text) != SyntaxKind.None)
+            {
+                RegisterRefactoring(context, expandedSpan, $@"<see langword=""{text}""/>");
+                return;
+            }
+
+            var memberDecl = token.Parent.GetAncestorOrThis<MemberDeclarationSyntax>();
+            if (memberDecl == null)
+            {
+                return;
+            }
+
+            expandedSpan = ExpandSpan(sourceText, span, includeDots: true);
+            text = sourceText.ToString(expandedSpan);
+
+            var semanticModel = await document.GetSemanticModelAsync(cancellationToken).ConfigureAwait(false);
+
+            var speculativePosition = memberDecl.GetLastToken().FullSpan.Start - 1;
+            if (!TryMatchTextAsSymbol(context, expandedSpan, text, semanticModel, speculativePosition, SpeculativeBindingOption.BindAsTypeOrNamespace) &&
+                !TryMatchTextAsSymbol(context, expandedSpan, text, semanticModel, speculativePosition, SpeculativeBindingOption.BindAsExpression))
+            {
+                return;
+            }
+        }
+
+        private void RegisterRefactoring(
+            CodeRefactoringContext context, TextSpan expandedSpan, string replacement)
+        {
+            context.RegisterRefactoring(new MyCodeAction(
+                string.Format(FeaturesResources.Use_0, replacement),
+                c => ReplaceTextAsync(context.Document, expandedSpan, replacement, c)));
+        }
+
+        private bool TryMatchTextAsSymbol(
+            CodeRefactoringContext context, TextSpan expandedSpan, 
+            string text, SemanticModel semanticModel, 
+            int speculativePosition, SpeculativeBindingOption binding)
+        {
+            var parsed = SyntaxFactory.ParseExpression(text);
+
+            var symbolInfo = semanticModel.GetSpeculativeSymbolInfo(speculativePosition, parsed, binding);
+            switch (symbolInfo.GetAnySymbol())
+            {
+                case IParameterSymbol parameter:
+                    RegisterRefactoring(context, expandedSpan, $@"<paramref name=""{text}""/>");
+                    return true;
+                case ITypeParameterSymbol typeParameter:
+                    RegisterRefactoring(context, expandedSpan, $@"<typeparamref name=""{text}""/>");
+                    return true;
+                case ISymbol symbol:
+                    RegisterRefactoring(context, expandedSpan, $@"<see cref=""{text}""/>");
+                    return true;
+                default:
+                    return false;
+            }
+        }
+
+        private async Task<Document> ReplaceTextAsync(
+            Document document, TextSpan span, string replacement, CancellationToken cancellationToken)
+        {
+            var text = await document.GetTextAsync(cancellationToken).ConfigureAwait(false);
+            var newText = text.Replace(span, replacement);
+
+            return document.WithText(newText);
+        }
+
+        private TextSpan ExpandSpan(SourceText sourceText, TextSpan span, bool includeDots)
+        {
+            if (span.Length != 0)
+            {
+                return span;
+            }
+
+            var start = span.Start;
+            var end = span.Start;
+            while (start > 0 && ExpandBackward(sourceText, start, includeDots))
+            {
+                start--;
+            }
+
+            while (end < sourceText.Length && ExpandForward(sourceText, end, includeDots))
+            {
+                end++;
+            }
+
+            return TextSpan.FromBounds(start, end);
+        }
+
+        private bool ExpandForward(SourceText sourceText, int end, bool includeDots)
+        {
+            var currentChar = sourceText[end];
+
+            if (char.IsLetterOrDigit(currentChar))
+            {
+                return true;
+            }
+
+            // Only consume a dot in front of the current word if it is part of a dotted
+            // word chain, and isn't just the end of a sentence.
+            if (includeDots && currentChar == '.' &&
+                end + 1 < sourceText.Length && char.IsLetterOrDigit(sourceText[end + 1]))
+            {
+                return true;
+            }
+
+            return false;
+        }
+
+        private bool ExpandBackward(
+            SourceText sourceText, int start, bool includeDots)
+        {
+            var previousCharacter = sourceText[start - 1];
+            if (char.IsLetterOrDigit(previousCharacter))
+            {
+                return true;
+            }
+
+            if (includeDots && previousCharacter == '.')
+            {
+                return true;
+            }
+
+            return false;
+        }
+
+        private class MyCodeAction : CodeAction.DocumentChangeAction
+        {
+            public MyCodeAction(string title, Func<CancellationToken, Task<Document>> createChangedDocument) 
+                : base(title, createChangedDocument)
+            {
+            }
+        }
+    }
+}
diff --git a/src/Features/Core/Portable/FeaturesResources.Designer.cs b/src/Features/Core/Portable/FeaturesResources.Designer.cs
index 84d9b1dd30be9..0e0ac0b45e2d7 100644
--- a/src/Features/Core/Portable/FeaturesResources.Designer.cs
+++ b/src/Features/Core/Portable/FeaturesResources.Designer.cs
@@ -3354,6 +3354,15 @@ internal class FeaturesResources {
             }
         }
         
+        /// <summary>
+        ///   Looks up a localized string similar to Use {0}.
+        /// </summary>
+        internal static string Use_0 {
+            get {
+                return ResourceManager.GetString("Use_0", resourceCulture);
+            }
+        }
+        
         /// <summary>
         ///   Looks up a localized string similar to Use auto property.
         /// </summary>
diff --git a/src/Features/Core/Portable/FeaturesResources.resx b/src/Features/Core/Portable/FeaturesResources.resx
index 78f762609b8cb..c2c7d0a5f392a 100644
--- a/src/Features/Core/Portable/FeaturesResources.resx
+++ b/src/Features/Core/Portable/FeaturesResources.resx
@@ -1301,4 +1301,7 @@ This version used in: {2}</value>
   <data name="Warning_Method_overrides_symbol_from_metadata" xml:space="preserve">
     <value>Warning: Method overrides symbol from metadata</value>
   </data>
+  <data name="Use_0" xml:space="preserve">
+    <value>Use {0}</value>
+  </data>
 </root>
\ No newline at end of file

From 930d5f219e6930f56b746b40060fcae4569fa658 Mon Sep 17 00:00:00 2001
From: CyrusNajmabadi <cyrusn@microsoft.com>
Date: Sat, 12 Aug 2017 16:27:04 -0700
Subject: [PATCH 43/77] rename types.

---
 ...SharpReplaceDocCommentTextWithTagCodeRefactoringProvider.cs} | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
 rename src/Features/CSharp/Portable/{ReplaceDocCommentTextWithSeeElement/ReplaceDocCommentTextWithSeeTagCodeRefactoringProvider.cs => ReplaceDocCommentTextWithTag/CSharpReplaceDocCommentTextWithTagCodeRefactoringProvider.cs} (98%)

diff --git a/src/Features/CSharp/Portable/ReplaceDocCommentTextWithSeeElement/ReplaceDocCommentTextWithSeeTagCodeRefactoringProvider.cs b/src/Features/CSharp/Portable/ReplaceDocCommentTextWithTag/CSharpReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
similarity index 98%
rename from src/Features/CSharp/Portable/ReplaceDocCommentTextWithSeeElement/ReplaceDocCommentTextWithSeeTagCodeRefactoringProvider.cs
rename to src/Features/CSharp/Portable/ReplaceDocCommentTextWithTag/CSharpReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
index 3e7eafe2f2527..f02a3307f2e93 100644
--- a/src/Features/CSharp/Portable/ReplaceDocCommentTextWithSeeElement/ReplaceDocCommentTextWithSeeTagCodeRefactoringProvider.cs
+++ b/src/Features/CSharp/Portable/ReplaceDocCommentTextWithTag/CSharpReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
@@ -15,7 +15,7 @@
 namespace Microsoft.CodeAnalysis.CSharp.ReplaceDocCommentTextWithSeeElement
 {
     [ExportCodeRefactoringProvider(LanguageNames.CSharp), Shared]
-    internal class ReplaceDocCommentTextWithSeeTagCodeRefactoringProvider : CodeRefactoringProvider
+    internal class CSharpReplaceDocCommentTextWithTagCodeRefactoringProvider : CodeRefactoringProvider
     {
         public override async Task ComputeRefactoringsAsync(CodeRefactoringContext context)
         {

From 11d1432cc2c38e8f6c1abbea07c6e6d1719aac24 Mon Sep 17 00:00:00 2001
From: CyrusNajmabadi <cyrusn@microsoft.com>
Date: Sat, 12 Aug 2017 16:51:38 -0700
Subject: [PATCH 44/77] Add tests.

---
 .../ReplaceDocCommentTextWithTagTests.cs      | 373 ++++++++++++++++++
 src/EditorFeatures/TestUtilities/Traits.cs    |   1 +
 2 files changed, 374 insertions(+)
 create mode 100644 src/EditorFeatures/CSharpTest/ReplaceDocCommentTextWithTag/ReplaceDocCommentTextWithTagTests.cs

diff --git a/src/EditorFeatures/CSharpTest/ReplaceDocCommentTextWithTag/ReplaceDocCommentTextWithTagTests.cs b/src/EditorFeatures/CSharpTest/ReplaceDocCommentTextWithTag/ReplaceDocCommentTextWithTagTests.cs
new file mode 100644
index 0000000000000..201f77c0ce374
--- /dev/null
+++ b/src/EditorFeatures/CSharpTest/ReplaceDocCommentTextWithTag/ReplaceDocCommentTextWithTagTests.cs
@@ -0,0 +1,373 @@
+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using System.Threading.Tasks;
+using Microsoft.CodeAnalysis.CodeRefactorings;
+using Microsoft.CodeAnalysis.CSharp.ReplaceDocCommentTextWithSeeElement;
+using Microsoft.CodeAnalysis.Editor.CSharp.UnitTests.CodeRefactorings;
+using Roslyn.Test.Utilities;
+using Xunit;
+
+namespace Microsoft.CodeAnalysis.Editor.CSharp.UnitTests.ReplaceDocCommentTextWithTag
+{
+    public class ReplaceDocCommentTextWithTagTests : AbstractCSharpCodeActionTest
+    {
+        protected override CodeRefactoringProvider CreateCodeRefactoringProvider(Workspace workspace, TestParameters parameters)
+            => new CSharpReplaceDocCommentTextWithTagCodeRefactoringProvider();
+
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)]
+        public async Task TestStartOfKeyword()
+        {
+            await TestInRegularAndScriptAsync(
+@"
+/// TKey must implement the System.IDisposable [||]interface.
+class C<TKey>
+{
+}",
+
+@"
+/// TKey must implement the System.IDisposable <see langword=""interface""/>.
+class C<TKey>
+{
+}");
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)]
+        public async Task TestEndOfKeyword()
+        {
+            await TestInRegularAndScriptAsync(
+@"
+/// TKey must implement the System.IDisposable interface[||].
+class C<TKey>
+{
+}",
+
+@"
+/// TKey must implement the System.IDisposable <see langword=""interface""/>.
+class C<TKey>
+{
+}");
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)]
+        public async Task TestEndOfKeyword_NewLineFollowing()
+        {
+            await TestInRegularAndScriptAsync(
+@"
+/// TKey must implement the System.IDisposable interface[||]
+class C<TKey>
+{
+}",
+
+@"
+/// TKey must implement the System.IDisposable <see langword=""interface""/>
+class C<TKey>
+{
+}");
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)]
+        public async Task TestSelectedKeyword()
+        {
+            await TestInRegularAndScriptAsync(
+@"
+/// TKey must implement the System.IDisposable [|interface|].
+class C<TKey>
+{
+}",
+
+@"
+/// TKey must implement the System.IDisposable <see langword=""interface""/>.
+class C<TKey>
+{
+}");
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)]
+        public async Task TestInsideKeyword()
+        {
+            await TestInRegularAndScriptAsync(
+@"
+/// TKey must implement the System.IDisposable int[||]erface.
+class C<TKey>
+{
+}",
+
+@"
+/// TKey must implement the System.IDisposable <see langword=""interface""/>.
+class C<TKey>
+{
+}");
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)]
+        public async Task TestNotInsideKeywordIfNonEmptySpan()
+        {
+            await TestMissingAsync(
+@"
+/// TKey must implement the System.IDisposable int[|erf|]ace
+class C<TKey>
+{
+}");
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)]
+        public async Task TestStartOfFullyQualifiedTypeName_Start()
+        {
+            await TestInRegularAndScriptAsync(
+@"
+/// TKey must implement the [||]System.IDisposable interface.
+class C<TKey>
+{
+}",
+
+@"
+/// TKey must implement the <see cref=""System.IDisposable""/> interface.
+class C<TKey>
+{
+}");
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)]
+        public async Task TestStartOfFullyQualifiedTypeName_Mid1()
+        {
+            await TestInRegularAndScriptAsync(
+@"
+/// TKey must implement the System[||].IDisposable interface.
+class C<TKey>
+{
+}",
+
+@"
+/// TKey must implement the <see cref=""System.IDisposable""/> interface.
+class C<TKey>
+{
+}");
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)]
+        public async Task TestStartOfFullyQualifiedTypeName_Mid2()
+        {
+            await TestInRegularAndScriptAsync(
+@"
+/// TKey must implement the System.[||]IDisposable interface.
+class C<TKey>
+{
+}",
+
+@"
+/// TKey must implement the <see cref=""System.IDisposable""/> interface.
+class C<TKey>
+{
+}");
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)]
+        public async Task TestStartOfFullyQualifiedTypeName_End()
+        {
+            await TestInRegularAndScriptAsync(
+@"
+/// TKey must implement the System.IDisposable[||] interface.
+class C<TKey>
+{
+}",
+
+@"
+/// TKey must implement the <see cref=""System.IDisposable""/> interface.
+class C<TKey>
+{
+}");
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)]
+        public async Task TestStartOfFullyQualifiedTypeName_Selected()
+        {
+            await TestInRegularAndScriptAsync(
+@"
+/// TKey must implement the [|System.IDisposable|] interface.
+class C<TKey>
+{
+}",
+
+@"
+/// TKey must implement the <see cref=""System.IDisposable""/> interface.
+class C<TKey>
+{
+}");
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)]
+        public async Task TestTypeParameterReference()
+        {
+            await TestInRegularAndScriptAsync(
+@"
+/// [||]TKey must implement the System.IDisposable interface.
+class C<TKey>
+{
+}",
+
+@"
+/// <typeparamref name=""TKey""/> must implement the System.IDisposable interface.
+class C<TKey>
+{
+}");
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)]
+        public async Task TestTypeParameterReference_EmptyClassBody()
+        {
+            await TestInRegularAndScriptAsync(
+@"
+/// [||]TKey must implement the System.IDisposable interface.
+class C<TKey>{}",
+
+@"
+/// <typeparamref name=""TKey""/> must implement the System.IDisposable interface.
+class C<TKey>{}");
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)]
+        public async Task TestCanSeeInnerMethod()
+        {
+            await TestInRegularAndScriptAsync(
+@"
+/// Use WriteLine[||] as a Console.WriteLine replacement
+class C
+{
+    void WriteLine<TKey>(TKey value) { }
+}",
+
+@"
+/// Use <see cref=""WriteLine""/> as a Console.WriteLine replacement
+class C
+{
+    void WriteLine<TKey>(TKey value) { }
+}");
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)]
+        public async Task TestNotOnMispelledName()
+        {
+            await TestMissingAsync(
+@"
+/// Use WriteLine1[||] as a Console.WriteLine replacement
+class C
+{
+    void WriteLine<TKey>(TKey value) { }
+}");
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)]
+        public async Task TestMethodTypeParameterSymbol()
+        {
+            await TestInRegularAndScriptAsync(
+@"
+class C
+{
+    /// value has type TKey[||] so we don't box primitives.
+    void WriteLine<TKey>(TKey value) { }
+}",
+
+@"
+class C
+{
+    /// value has type <typeparamref name=""TKey""/> so we don't box primitives.
+    void WriteLine<TKey>(TKey value) { }
+}");
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)]
+        public async Task TestMethodTypeParameterSymbol_EmptyBody()
+        {
+            await TestInRegularAndScriptAsync(
+@"
+class C
+{
+    /// value has type TKey[||] so we don't box primitives.
+    void WriteLine<TKey>(TKey value){}
+}",
+
+@"
+class C
+{
+    /// value has type <typeparamref name=""TKey""/> so we don't box primitives.
+    void WriteLine<TKey>(TKey value){}
+}");
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)]
+        public async Task TestMethodTypeParameterSymbol_ExpressionBody()
+        {
+            await TestInRegularAndScriptAsync(
+@"
+class C
+{
+    /// value has type TKey[||] so we don't box primitives.
+    object WriteLine<TKey>(TKey value) => null;
+}",
+
+@"
+class C
+{
+    /// value has type <typeparamref name=""TKey""/> so we don't box primitives.
+    object WriteLine<TKey>(TKey value) => null;
+}");
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)]
+        public async Task TestMethodParameterSymbol()
+        {
+            await TestInRegularAndScriptAsync(
+@"
+class C
+{
+    /// value[||] has type TKey so we don't box primitives.
+    void WriteLine<TKey>(TKey value) { }
+}",
+
+@"
+class C
+{
+    /// <paramref name=""value""/> has type TKey so we don't box primitives.
+    void WriteLine<TKey>(TKey value) { }
+}");
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)]
+        public async Task TestMethodParameterSymbol_EmptyBody()
+        {
+            await TestInRegularAndScriptAsync(
+@"
+class C
+{
+    /// value[||] has type TKey so we don't box primitives.
+    void WriteLine<TKey>(TKey value){}
+}",
+
+@"
+class C
+{
+    /// <paramref name=""value""/> has type TKey so we don't box primitives.
+    void WriteLine<TKey>(TKey value){}
+}");
+        }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)]
+        public async Task TestMethodParameterSymbol_ExpressionBody()
+        {
+            await TestInRegularAndScriptAsync(
+@"
+class C
+{
+    /// value[||] has type TKey so we don't box primitives.
+    object WriteLine<TKey>(TKey value) => null;
+}",
+
+@"
+class C
+{
+    /// <paramref name=""value""/> has type TKey so we don't box primitives.
+    object WriteLine<TKey>(TKey value) => null;
+}");
+        }
+    }
+}
diff --git a/src/EditorFeatures/TestUtilities/Traits.cs b/src/EditorFeatures/TestUtilities/Traits.cs
index 8e03c0de49996..3c650a7d7d7f5 100644
--- a/src/EditorFeatures/TestUtilities/Traits.cs
+++ b/src/EditorFeatures/TestUtilities/Traits.cs
@@ -85,6 +85,7 @@ public static class Features
             public const string CodeActionsOrderModifiers = "CodeActions.OrderModifiers";
             public const string CodeActionsPopulateSwitch = "CodeActions.PopulateSwitch";
             public const string CodeActionsQualifyMemberAccess = "CodeActions.QualifyMemberAccess";
+            public const string CodeActionsReplaceDocCommentTextWithTag = "CodeActions.ReplaceDocCommentTextWithTag";
             public const string CodeActionsReplaceMethodWithProperty = "CodeActions.ReplaceMethodWithProperty";
             public const string CodeActionsReplacePropertyWithMethods = "CodeActions.ReplacePropertyWithMethods";
             public const string CodeActionsRemoveByVal = "CodeActions.RemoveByVal";

From 8e298f2a26297255c5d38d316becce1fcbb2be99 Mon Sep 17 00:00:00 2001
From: CyrusNajmabadi <cyrusn@microsoft.com>
Date: Sat, 12 Aug 2017 16:59:10 -0700
Subject: [PATCH 45/77] Update namespace

---
 .../ReplaceDocCommentTextWithTagTests.cs                      | 2 +-
 ...harpReplaceDocCommentTextWithTagCodeRefactoringProvider.cs | 4 +---
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/src/EditorFeatures/CSharpTest/ReplaceDocCommentTextWithTag/ReplaceDocCommentTextWithTagTests.cs b/src/EditorFeatures/CSharpTest/ReplaceDocCommentTextWithTag/ReplaceDocCommentTextWithTagTests.cs
index 201f77c0ce374..4734906bac1af 100644
--- a/src/EditorFeatures/CSharpTest/ReplaceDocCommentTextWithTag/ReplaceDocCommentTextWithTagTests.cs
+++ b/src/EditorFeatures/CSharpTest/ReplaceDocCommentTextWithTag/ReplaceDocCommentTextWithTagTests.cs
@@ -2,7 +2,7 @@
 
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.CodeRefactorings;
-using Microsoft.CodeAnalysis.CSharp.ReplaceDocCommentTextWithSeeElement;
+using Microsoft.CodeAnalysis.CSharp.ReplaceDocCommentTextWithTag;
 using Microsoft.CodeAnalysis.Editor.CSharp.UnitTests.CodeRefactorings;
 using Roslyn.Test.Utilities;
 using Xunit;
diff --git a/src/Features/CSharp/Portable/ReplaceDocCommentTextWithTag/CSharpReplaceDocCommentTextWithTagCodeRefactoringProvider.cs b/src/Features/CSharp/Portable/ReplaceDocCommentTextWithTag/CSharpReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
index f02a3307f2e93..9df13421faf0e 100644
--- a/src/Features/CSharp/Portable/ReplaceDocCommentTextWithTag/CSharpReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
+++ b/src/Features/CSharp/Portable/ReplaceDocCommentTextWithTag/CSharpReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
@@ -1,9 +1,7 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
 using System;
-using System.Collections.Generic;
 using System.Composition;
-using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.CodeAnalysis.CodeActions;
@@ -12,7 +10,7 @@
 using Microsoft.CodeAnalysis.Shared.Extensions;
 using Microsoft.CodeAnalysis.Text;
 
-namespace Microsoft.CodeAnalysis.CSharp.ReplaceDocCommentTextWithSeeElement
+namespace Microsoft.CodeAnalysis.CSharp.ReplaceDocCommentTextWithTag
 {
     [ExportCodeRefactoringProvider(LanguageNames.CSharp), Shared]
     internal class CSharpReplaceDocCommentTextWithTagCodeRefactoringProvider : CodeRefactoringProvider

From f7cf5d491ee2a57dd57ef9abf5f3239abdcbfe42 Mon Sep 17 00:00:00 2001
From: CyrusNajmabadi <cyrusn@microsoft.com>
Date: Sat, 12 Aug 2017 17:00:26 -0700
Subject: [PATCH 46/77] Rename parameter.

---
 ...ommentTextWithTagCodeRefactoringProvider.cs | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/src/Features/CSharp/Portable/ReplaceDocCommentTextWithTag/CSharpReplaceDocCommentTextWithTagCodeRefactoringProvider.cs b/src/Features/CSharp/Portable/ReplaceDocCommentTextWithTag/CSharpReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
index 9df13421faf0e..20178f5c49868 100644
--- a/src/Features/CSharp/Portable/ReplaceDocCommentTextWithTag/CSharpReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
+++ b/src/Features/CSharp/Portable/ReplaceDocCommentTextWithTag/CSharpReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
@@ -37,7 +37,7 @@ public override async Task ComputeRefactoringsAsync(CodeRefactoringContext conte
 
             var sourceText = await document.GetTextAsync(cancellationToken).ConfigureAwait(false);
 
-            var expandedSpan = ExpandSpan(sourceText, span, includeDots: false);
+            var expandedSpan = ExpandSpan(sourceText, span, fullyQualifiedName: false);
             var text = sourceText.ToString(expandedSpan);
 
             if (SyntaxFacts.GetKeywordKind(text) != SyntaxKind.None ||
@@ -53,7 +53,7 @@ public override async Task ComputeRefactoringsAsync(CodeRefactoringContext conte
                 return;
             }
 
-            expandedSpan = ExpandSpan(sourceText, span, includeDots: true);
+            expandedSpan = ExpandSpan(sourceText, span, fullyQualifiedName: true);
             text = sourceText.ToString(expandedSpan);
 
             var semanticModel = await document.GetSemanticModelAsync(cancellationToken).ConfigureAwait(false);
@@ -107,7 +107,7 @@ public override async Task ComputeRefactoringsAsync(CodeRefactoringContext conte
             return document.WithText(newText);
         }
 
-        private TextSpan ExpandSpan(SourceText sourceText, TextSpan span, bool includeDots)
+        private TextSpan ExpandSpan(SourceText sourceText, TextSpan span, bool fullyQualifiedName)
         {
             if (span.Length != 0)
             {
@@ -116,12 +116,12 @@ private TextSpan ExpandSpan(SourceText sourceText, TextSpan span, bool includeDo
 
             var start = span.Start;
             var end = span.Start;
-            while (start > 0 && ExpandBackward(sourceText, start, includeDots))
+            while (start > 0 && ExpandBackward(sourceText, start, fullyQualifiedName))
             {
                 start--;
             }
 
-            while (end < sourceText.Length && ExpandForward(sourceText, end, includeDots))
+            while (end < sourceText.Length && ExpandForward(sourceText, end, fullyQualifiedName))
             {
                 end++;
             }
@@ -129,7 +129,7 @@ private TextSpan ExpandSpan(SourceText sourceText, TextSpan span, bool includeDo
             return TextSpan.FromBounds(start, end);
         }
 
-        private bool ExpandForward(SourceText sourceText, int end, bool includeDots)
+        private bool ExpandForward(SourceText sourceText, int end, bool fullyQualifiedName)
         {
             var currentChar = sourceText[end];
 
@@ -140,7 +140,7 @@ private bool ExpandForward(SourceText sourceText, int end, bool includeDots)
 
             // Only consume a dot in front of the current word if it is part of a dotted
             // word chain, and isn't just the end of a sentence.
-            if (includeDots && currentChar == '.' &&
+            if (fullyQualifiedName && currentChar == '.' &&
                 end + 1 < sourceText.Length && char.IsLetterOrDigit(sourceText[end + 1]))
             {
                 return true;
@@ -150,7 +150,7 @@ private bool ExpandForward(SourceText sourceText, int end, bool includeDots)
         }
 
         private bool ExpandBackward(
-            SourceText sourceText, int start, bool includeDots)
+            SourceText sourceText, int start, bool fullyQualifiedName)
         {
             var previousCharacter = sourceText[start - 1];
             if (char.IsLetterOrDigit(previousCharacter))
@@ -158,7 +158,7 @@ private bool ExpandForward(SourceText sourceText, int end, bool includeDots)
                 return true;
             }
 
-            if (includeDots && previousCharacter == '.')
+            if (fullyQualifiedName && previousCharacter == '.')
             {
                 return true;
             }

From 373915ad3ee37e33f5d3506151fae6f9206a7b49 Mon Sep 17 00:00:00 2001
From: CyrusNajmabadi <cyrusn@microsoft.com>
Date: Sat, 12 Aug 2017 17:53:28 -0700
Subject: [PATCH 47/77] Extract out common core so we can produce a VB version.

---
 .../ReplaceDocCommentTextWithTagTests.cs      |  39 +++
 ...mmentTextWithTagCodeRefactoringProvider.cs | 174 +-----------
 ...mmentTextWithTagCodeRefactoringProvider.cs | 251 ++++++++++++++++++
 .../Shared/Extensions/ISymbolExtensions.cs    |   4 +-
 4 files changed, 303 insertions(+), 165 deletions(-)
 create mode 100644 src/Features/Core/Portable/ReplaceDocCommentTextWithTag/AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider.cs

diff --git a/src/EditorFeatures/CSharpTest/ReplaceDocCommentTextWithTag/ReplaceDocCommentTextWithTagTests.cs b/src/EditorFeatures/CSharpTest/ReplaceDocCommentTextWithTag/ReplaceDocCommentTextWithTagTests.cs
index 4734906bac1af..88ca6484e24a6 100644
--- a/src/EditorFeatures/CSharpTest/ReplaceDocCommentTextWithTag/ReplaceDocCommentTextWithTagTests.cs
+++ b/src/EditorFeatures/CSharpTest/ReplaceDocCommentTextWithTag/ReplaceDocCommentTextWithTagTests.cs
@@ -313,6 +313,25 @@ class C
 }");
         }
 
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)]
+        public async Task TestMethodTypeParameter_SemicolonBody()
+        {
+            await TestInRegularAndScriptAsync(
+@"
+class C
+{
+    /// value has type TKey[||] so we don't box primitives.
+    void WriteLine<TKey>(TKey value);
+}",
+
+@"
+class C
+{
+    /// value has type <typeparamref name=""TKey""/> so we don't box primitives.
+    void WriteLine<TKey>(TKey value);
+}");
+        }
+
         [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)]
         public async Task TestMethodParameterSymbol()
         {
@@ -369,5 +388,25 @@ class C
     object WriteLine<TKey>(TKey value) => null;
 }");
         }
+
+        [Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)]
+        public async Task TestMethodParameterSymbol_SemicolonBody()
+        {
+            await TestInRegularAndScriptAsync(
+@"
+class C
+{
+    /// value[||] has type TKey so we don't box primitives.
+    void WriteLine<TKey>(TKey value);
+}",
+
+@"
+class C
+{
+    /// <paramref name=""value""/> has type TKey so we don't box primitives.
+    void WriteLine<TKey>(TKey value);
+}");
+        }
+
     }
 }
diff --git a/src/Features/CSharp/Portable/ReplaceDocCommentTextWithTag/CSharpReplaceDocCommentTextWithTagCodeRefactoringProvider.cs b/src/Features/CSharp/Portable/ReplaceDocCommentTextWithTag/CSharpReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
index 20178f5c49868..60b5cfa758983 100644
--- a/src/Features/CSharp/Portable/ReplaceDocCommentTextWithTag/CSharpReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
+++ b/src/Features/CSharp/Portable/ReplaceDocCommentTextWithTag/CSharpReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
@@ -1,177 +1,25 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
-using System;
 using System.Composition;
-using System.Threading;
-using System.Threading.Tasks;
-using Microsoft.CodeAnalysis.CodeActions;
 using Microsoft.CodeAnalysis.CodeRefactorings;
 using Microsoft.CodeAnalysis.CSharp.Syntax;
-using Microsoft.CodeAnalysis.Shared.Extensions;
-using Microsoft.CodeAnalysis.Text;
+using Microsoft.CodeAnalysis.ReplaceDocCommentTextWithTag;
 
 namespace Microsoft.CodeAnalysis.CSharp.ReplaceDocCommentTextWithTag
 {
     [ExportCodeRefactoringProvider(LanguageNames.CSharp), Shared]
-    internal class CSharpReplaceDocCommentTextWithTagCodeRefactoringProvider : CodeRefactoringProvider
+    internal class CSharpReplaceDocCommentTextWithTagCodeRefactoringProvider :
+        AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider<MemberDeclarationSyntax>
     {
-        public override async Task ComputeRefactoringsAsync(CodeRefactoringContext context)
-        {
-            var document = context.Document;
-            var span = context.Span;
-            var cancellationToken = context.CancellationToken;
+        protected override bool IsXmlTextToken(SyntaxToken token)
+            => token.Kind() == SyntaxKind.XmlTextLiteralToken ||
+               token.Kind() == SyntaxKind.XmlTextLiteralNewLineToken;
 
-            var root = await document.GetSyntaxRootAsync(cancellationToken).ConfigureAwait(false);
-            var token = root.FindToken(span.Start, findInsideTrivia: true);
+        protected override bool IsAnyKeyword(string text)
+            => SyntaxFacts.GetKeywordKind(text) != SyntaxKind.None ||
+               SyntaxFacts.GetContextualKeywordKind(text) != SyntaxKind.None;
 
-            if (token.Kind() != SyntaxKind.XmlTextLiteralToken &&
-                token.Kind() != SyntaxKind.XmlTextLiteralNewLineToken)
-            {
-                return;
-            }
-
-            if (!token.FullSpan.Contains(span))
-            {
-                return;
-            }
-
-            var sourceText = await document.GetTextAsync(cancellationToken).ConfigureAwait(false);
-
-            var expandedSpan = ExpandSpan(sourceText, span, fullyQualifiedName: false);
-            var text = sourceText.ToString(expandedSpan);
-
-            if (SyntaxFacts.GetKeywordKind(text) != SyntaxKind.None ||
-                SyntaxFacts.GetContextualKeywordKind(text) != SyntaxKind.None)
-            {
-                RegisterRefactoring(context, expandedSpan, $@"<see langword=""{text}""/>");
-                return;
-            }
-
-            var memberDecl = token.Parent.GetAncestorOrThis<MemberDeclarationSyntax>();
-            if (memberDecl == null)
-            {
-                return;
-            }
-
-            expandedSpan = ExpandSpan(sourceText, span, fullyQualifiedName: true);
-            text = sourceText.ToString(expandedSpan);
-
-            var semanticModel = await document.GetSemanticModelAsync(cancellationToken).ConfigureAwait(false);
-
-            var speculativePosition = memberDecl.GetLastToken().FullSpan.Start - 1;
-            if (!TryMatchTextAsSymbol(context, expandedSpan, text, semanticModel, speculativePosition, SpeculativeBindingOption.BindAsTypeOrNamespace) &&
-                !TryMatchTextAsSymbol(context, expandedSpan, text, semanticModel, speculativePosition, SpeculativeBindingOption.BindAsExpression))
-            {
-                return;
-            }
-        }
-
-        private void RegisterRefactoring(
-            CodeRefactoringContext context, TextSpan expandedSpan, string replacement)
-        {
-            context.RegisterRefactoring(new MyCodeAction(
-                string.Format(FeaturesResources.Use_0, replacement),
-                c => ReplaceTextAsync(context.Document, expandedSpan, replacement, c)));
-        }
-
-        private bool TryMatchTextAsSymbol(
-            CodeRefactoringContext context, TextSpan expandedSpan, 
-            string text, SemanticModel semanticModel, 
-            int speculativePosition, SpeculativeBindingOption binding)
-        {
-            var parsed = SyntaxFactory.ParseExpression(text);
-
-            var symbolInfo = semanticModel.GetSpeculativeSymbolInfo(speculativePosition, parsed, binding);
-            switch (symbolInfo.GetAnySymbol())
-            {
-                case IParameterSymbol parameter:
-                    RegisterRefactoring(context, expandedSpan, $@"<paramref name=""{text}""/>");
-                    return true;
-                case ITypeParameterSymbol typeParameter:
-                    RegisterRefactoring(context, expandedSpan, $@"<typeparamref name=""{text}""/>");
-                    return true;
-                case ISymbol symbol:
-                    RegisterRefactoring(context, expandedSpan, $@"<see cref=""{text}""/>");
-                    return true;
-                default:
-                    return false;
-            }
-        }
-
-        private async Task<Document> ReplaceTextAsync(
-            Document document, TextSpan span, string replacement, CancellationToken cancellationToken)
-        {
-            var text = await document.GetTextAsync(cancellationToken).ConfigureAwait(false);
-            var newText = text.Replace(span, replacement);
-
-            return document.WithText(newText);
-        }
-
-        private TextSpan ExpandSpan(SourceText sourceText, TextSpan span, bool fullyQualifiedName)
-        {
-            if (span.Length != 0)
-            {
-                return span;
-            }
-
-            var start = span.Start;
-            var end = span.Start;
-            while (start > 0 && ExpandBackward(sourceText, start, fullyQualifiedName))
-            {
-                start--;
-            }
-
-            while (end < sourceText.Length && ExpandForward(sourceText, end, fullyQualifiedName))
-            {
-                end++;
-            }
-
-            return TextSpan.FromBounds(start, end);
-        }
-
-        private bool ExpandForward(SourceText sourceText, int end, bool fullyQualifiedName)
-        {
-            var currentChar = sourceText[end];
-
-            if (char.IsLetterOrDigit(currentChar))
-            {
-                return true;
-            }
-
-            // Only consume a dot in front of the current word if it is part of a dotted
-            // word chain, and isn't just the end of a sentence.
-            if (fullyQualifiedName && currentChar == '.' &&
-                end + 1 < sourceText.Length && char.IsLetterOrDigit(sourceText[end + 1]))
-            {
-                return true;
-            }
-
-            return false;
-        }
-
-        private bool ExpandBackward(
-            SourceText sourceText, int start, bool fullyQualifiedName)
-        {
-            var previousCharacter = sourceText[start - 1];
-            if (char.IsLetterOrDigit(previousCharacter))
-            {
-                return true;
-            }
-
-            if (fullyQualifiedName && previousCharacter == '.')
-            {
-                return true;
-            }
-
-            return false;
-        }
-
-        private class MyCodeAction : CodeAction.DocumentChangeAction
-        {
-            public MyCodeAction(string title, Func<CancellationToken, Task<Document>> createChangedDocument) 
-                : base(title, createChangedDocument)
-            {
-            }
-        }
+        protected override SyntaxNode ParseExpression(string text)
+            => SyntaxFactory.ParseExpression(text);
     }
 }
diff --git a/src/Features/Core/Portable/ReplaceDocCommentTextWithTag/AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider.cs b/src/Features/Core/Portable/ReplaceDocCommentTextWithTag/AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
new file mode 100644
index 0000000000000..91dbb0bcc33ea
--- /dev/null
+++ b/src/Features/Core/Portable/ReplaceDocCommentTextWithTag/AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
@@ -0,0 +1,251 @@
+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using System;
+using System.Composition;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Microsoft.CodeAnalysis.CodeActions;
+using Microsoft.CodeAnalysis.CodeRefactorings;
+using Microsoft.CodeAnalysis.LanguageServices;
+using Microsoft.CodeAnalysis.Shared.Extensions;
+using Microsoft.CodeAnalysis.Text;
+
+namespace Microsoft.CodeAnalysis.ReplaceDocCommentTextWithTag
+{
+    internal abstract class AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider<TMemberDeclarationSyntax>
+        : CodeRefactoringProvider
+        where TMemberDeclarationSyntax : SyntaxNode
+    {
+        protected abstract bool IsAnyKeyword(string text);
+        protected abstract bool IsXmlTextToken(SyntaxToken token);
+        protected abstract SyntaxNode ParseExpression(string text);
+
+        public override async Task ComputeRefactoringsAsync(CodeRefactoringContext context)
+        {
+            var document = context.Document;
+            var span = context.Span;
+            var cancellationToken = context.CancellationToken;
+
+            var root = await document.GetSyntaxRootAsync(cancellationToken).ConfigureAwait(false);
+            var token = root.FindToken(span.Start, findInsideTrivia: true);
+
+            if (!IsXmlTextToken(token))
+            {
+                return;
+            }
+
+            if (!token.FullSpan.Contains(span))
+            {
+                return;
+            }
+
+            var sourceText = await document.GetTextAsync(cancellationToken).ConfigureAwait(false);
+
+            var singleWordSpan = ExpandSpan(sourceText, span, fullyQualifiedName: false);
+            var singleWordText = sourceText.ToString(singleWordSpan);
+            if (singleWordText == "")
+            {
+                return;
+            }
+
+            // First see if they're on a keyword. 
+            if (IsAnyKeyword(singleWordText))
+            {
+                RegisterRefactoring(context, singleWordSpan, $@"<see langword=""{singleWordText}""/>");
+                return;
+            }
+
+            // Not a keyword, see if it semantically means anything in the current context.
+            var semanticModel = await document.GetSemanticModelAsync(cancellationToken).ConfigureAwait(false);
+            var symbol = GetEnclosingSymbol(semanticModel, span.Start, cancellationToken);
+            if (symbol == null)
+            {
+                return;
+            }
+
+            // See if we can expand the term out to a fully qualified name. Do this
+            // first in case the user has something like X.memberName.  We don't want 
+            // to try to bind "memberName" first as it might bind to something like 
+            // a parameter, which is not what the user intends
+            var fullyQualifiedSpan = ExpandSpan(sourceText, span, fullyQualifiedName: true);
+            if (fullyQualifiedSpan != singleWordSpan)
+            {
+                var fullyQualifiedText = sourceText.ToString(fullyQualifiedSpan);
+                if (TryParseAndBindText(context, semanticModel, token, fullyQualifiedSpan, fullyQualifiedText))
+                {
+                    return;
+                }
+            }
+
+            // Check if the single word could be binding to a type parameter or parameter
+            // for the current symbol.
+            var syntaxFacts = document.GetLanguageService<ISyntaxFactsService>();
+            var parameter = symbol.GetParameters().FirstOrDefault(p => syntaxFacts.StringComparer.Equals(p.Name, singleWordText));
+            if (parameter != null)
+            {
+                RegisterRefactoring(context, singleWordSpan, $@"<paramref name=""{singleWordText}""/>");
+                return;
+            }
+
+            var typeParameter = symbol.GetTypeParameters().FirstOrDefault(t => syntaxFacts.StringComparer.Equals(t.Name, singleWordText));
+            if (typeParameter != null)
+            {
+                RegisterRefactoring(context, singleWordSpan, $@"<typeparamref name=""{singleWordText}""/>");
+                return;
+            }
+
+            // Look up the term inside the named type if we're inside of one.
+            if (symbol is INamedTypeSymbol namedType)
+            {
+                var childMember = namedType.GetMembers().FirstOrDefault(m => syntaxFacts.StringComparer.Equals(m.Name, singleWordText));
+                if (childMember != null)
+                {
+                    RegisterRefactoring(context, singleWordSpan, $@"<see cref=""{singleWordText}""/>");
+                    return;
+                }
+            }
+
+            // Finally, try to speculatively bind the name and see if it binds to anything
+            // in the surrounding context.
+            TryParseAndBindText(context, semanticModel, token, singleWordSpan, singleWordText);
+        }
+
+        private bool TryParseAndBindText(
+            CodeRefactoringContext context, SemanticModel semanticModel, SyntaxToken token, TextSpan replacementSpan, string text)
+        {
+            var parsed = ParseExpression(text);
+            var foundSymbol = semanticModel.GetSpeculativeSymbolInfo(token.SpanStart, parsed, SpeculativeBindingOption.BindAsExpression).GetAnySymbol();
+            if (foundSymbol == null)
+            {
+                return false;
+            }
+
+            RegisterRefactoring(context, replacementSpan, $@"<see cref=""{text}""/>");
+            return true;
+        }
+
+        private ISymbol GetEnclosingSymbol(SemanticModel semanticModel, int position, CancellationToken cancellationToken)
+        {
+            var root = semanticModel.SyntaxTree.GetRoot(cancellationToken);
+            var token = root.FindToken(position);
+
+            for (var node = token.Parent; node != null; node = node.Parent)
+            {
+                if (semanticModel.GetDeclaredSymbol(node) is ISymbol declaration)
+                {
+                    return declaration;
+                }
+            }
+
+            return null;
+        }
+
+        private void RegisterRefactoring(
+            CodeRefactoringContext context, TextSpan expandedSpan, string replacement)
+        {
+            context.RegisterRefactoring(new MyCodeAction(
+                string.Format(FeaturesResources.Use_0, replacement),
+                c => ReplaceTextAsync(context.Document, expandedSpan, replacement, c)));
+        }
+
+        //private bool TryMatchTextAsSymbol(
+        //    CodeRefactoringContext context, TextSpan expandedSpan, 
+        //    string text, SemanticModel semanticModel, 
+        //    int speculativePosition, SpeculativeBindingOption binding)
+        //{
+        //    var parsed = ParseExpression(text);
+
+        //    var symbolInfo = semanticModel.GetSpeculativeSymbolInfo(speculativePosition, parsed, binding);
+        //    switch (symbolInfo.GetAnySymbol())
+        //    {
+        //        case IParameterSymbol parameter:
+                    
+        //            return true;
+        //        case ITypeParameterSymbol typeParameter:
+        //            return true;
+        //        case ISymbol symbol:
+        //            RegisterRefactoring(context, expandedSpan, $@"<see cref=""{text}""/>");
+        //            return true;
+        //        default:
+        //            return false;
+        //    }
+        //}
+
+        private async Task<Document> ReplaceTextAsync(
+            Document document, TextSpan span, string replacement, CancellationToken cancellationToken)
+        {
+            var text = await document.GetTextAsync(cancellationToken).ConfigureAwait(false);
+            var newText = text.Replace(span, replacement);
+
+            return document.WithText(newText);
+        }
+
+        private TextSpan ExpandSpan(SourceText sourceText, TextSpan span, bool fullyQualifiedName)
+        {
+            if (span.Length != 0)
+            {
+                return span;
+            }
+
+            var start = span.Start;
+            var end = span.Start;
+            while (start > 0 && ExpandBackward(sourceText, start, fullyQualifiedName))
+            {
+                start--;
+            }
+
+            while (end < sourceText.Length && ExpandForward(sourceText, end, fullyQualifiedName))
+            {
+                end++;
+            }
+
+            return TextSpan.FromBounds(start, end);
+        }
+
+        private bool ExpandForward(SourceText sourceText, int end, bool fullyQualifiedName)
+        {
+            var currentChar = sourceText[end];
+
+            if (char.IsLetterOrDigit(currentChar))
+            {
+                return true;
+            }
+
+            // Only consume a dot in front of the current word if it is part of a dotted
+            // word chain, and isn't just the end of a sentence.
+            if (fullyQualifiedName && currentChar == '.' &&
+                end + 1 < sourceText.Length && char.IsLetterOrDigit(sourceText[end + 1]))
+            {
+                return true;
+            }
+
+            return false;
+        }
+
+        private bool ExpandBackward(
+            SourceText sourceText, int start, bool fullyQualifiedName)
+        {
+            var previousCharacter = sourceText[start - 1];
+            if (char.IsLetterOrDigit(previousCharacter))
+            {
+                return true;
+            }
+
+            if (fullyQualifiedName && previousCharacter == '.')
+            {
+                return true;
+            }
+
+            return false;
+        }
+
+        private class MyCodeAction : CodeAction.DocumentChangeAction
+        {
+            public MyCodeAction(string title, Func<CancellationToken, Task<Document>> createChangedDocument) 
+                : base(title, createChangedDocument)
+            {
+            }
+        }
+    }
+}
diff --git a/src/Workspaces/Core/Portable/Shared/Extensions/ISymbolExtensions.cs b/src/Workspaces/Core/Portable/Shared/Extensions/ISymbolExtensions.cs
index d4ceffdd7b8ae..e2e486fc54df7 100644
--- a/src/Workspaces/Core/Portable/Shared/Extensions/ISymbolExtensions.cs
+++ b/src/Workspaces/Core/Portable/Shared/Extensions/ISymbolExtensions.cs
@@ -418,7 +418,7 @@ public static ImmutableArray<IParameterSymbol> GetParameters(this ISymbol symbol
             {
                 case IMethodSymbol m: return m.Parameters;
                 case IPropertySymbol nt: return nt.Parameters;
-                default: return ImmutableArray.Create<IParameterSymbol>();
+                default: return ImmutableArray<IParameterSymbol>.Empty;
             }
         }
 
@@ -428,7 +428,7 @@ public static ImmutableArray<ITypeParameterSymbol> GetTypeParameters(this ISymbo
             {
                 case IMethodSymbol m: return m.TypeParameters;
                 case INamedTypeSymbol nt: return nt.TypeParameters;
-                default: return ImmutableArray.Create<ITypeParameterSymbol>();
+                default: return ImmutableArray<ITypeParameterSymbol>.Empty;
             }
         }
 

From d393695721554b2ef6351af1e6d3608a3e76c307 Mon Sep 17 00:00:00 2001
From: CyrusNajmabadi <cyrusn@microsoft.com>
Date: Sat, 12 Aug 2017 18:18:00 -0700
Subject: [PATCH 48/77] Add VB implementation and tests.

---
 .../ReplaceDocCommentTextWithTagTests.vb      | 319 ++++++++++++++++++
 ...mmentTextWithTagCodeRefactoringProvider.cs |   2 +-
 ...mmentTextWithTagCodeRefactoringProvider.cs |   4 +-
 ...mmentTextWithTagCodeRefactoringProvider.vb |  26 ++
 4 files changed, 347 insertions(+), 4 deletions(-)
 create mode 100644 src/EditorFeatures/VisualBasicTest/ReplaceDocCommentTextWithTag/ReplaceDocCommentTextWithTagTests.vb
 create mode 100644 src/Features/VisualBasic/Portable/ReplaceDocCommentTextWithTag/VisualBasicReplaceDocCommentTextWithTagCodeRefactoringProvider.vb

diff --git a/src/EditorFeatures/VisualBasicTest/ReplaceDocCommentTextWithTag/ReplaceDocCommentTextWithTagTests.vb b/src/EditorFeatures/VisualBasicTest/ReplaceDocCommentTextWithTag/ReplaceDocCommentTextWithTagTests.vb
new file mode 100644
index 0000000000000..79c08c2e15ddc
--- /dev/null
+++ b/src/EditorFeatures/VisualBasicTest/ReplaceDocCommentTextWithTag/ReplaceDocCommentTextWithTagTests.vb
@@ -0,0 +1,319 @@
+' Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+Imports Microsoft.CodeAnalysis.CodeRefactorings
+Imports Microsoft.CodeAnalysis.Editor.VisualBasic.UnitTests.CodeRefactorings
+Imports Microsoft.CodeAnalysis.VisualBasic.ReplaceDocCommentTextWithTag
+
+Namespace Microsoft.CodeAnalysis.Editor.VisualBasic.UnitTests.ReplaceDocCommentTextWithTag
+    Public Class ReplaceDocCommentTextWithTagTests
+        Inherits AbstractVisualBasicCodeActionTest
+
+        Protected Overrides Function CreateCodeRefactoringProvider(Workspace As Workspace, parameters As TestParameters) As CodeRefactoringProvider
+            Return New VisualBasicReplaceDocCommentTextWithTagCodeRefactoringProvider()
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)>
+        Public Async Function TestStartOfKeyword() As Task
+            Await TestInRegularAndScriptAsync(
+"
+''' TKey must implement the System.IDisposable [||]interface.
+class C(Of TKey)
+end class",
+"
+''' TKey must implement the System.IDisposable <see langword=""interface""/>.
+class C(Of TKey)
+end class")
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)>
+        Public Async Function TestStartOfKeywordCapitalized() As Task
+            Await TestInRegularAndScriptAsync(
+"
+''' TKey must implement the System.IDisposable [||]Interface.
+class C(Of TKey)
+end class",
+"
+''' TKey must implement the System.IDisposable <see langword=""Interface""/>.
+class C(Of TKey)
+end class")
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)>
+        Public Async Function TestEndOfKeyword() As Task
+            Await TestInRegularAndScriptAsync(
+"
+''' TKey must implement the System.IDisposable interface[||].
+class C(Of TKey)
+end class",
+"
+''' TKey must implement the System.IDisposable <see langword=""interface""/>.
+class C(Of TKey)
+end class")
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)>
+        Public Async Function TestEndOfKeyword_NewLineFollowing() As Task
+            Await TestInRegularAndScriptAsync(
+"
+''' TKey must implement the System.IDisposable interface[||]
+class C(Of TKey)
+end class",
+"
+''' TKey must implement the System.IDisposable <see langword=""interface""/>
+class C(Of TKey)
+end class")
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)>
+        Public Async Function TestSelectedKeyword() As Task
+            Await TestInRegularAndScriptAsync(
+"
+''' TKey must implement the System.IDisposable [|interface|].
+class C(Of TKey)
+end class",
+"
+''' TKey must implement the System.IDisposable <see langword=""interface""/>.
+class C(Of TKey)
+end class")
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)>
+        Public Async Function TestInsideKeyword() As Task
+            Await TestInRegularAndScriptAsync(
+"
+''' TKey must implement the System.IDisposable int[||]erface.
+class C(Of TKey)
+end class",
+"
+''' TKey must implement the System.IDisposable <see langword=""interface""/>.
+class C(Of TKey)
+end class")
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)>
+        Public Async Function TestNotInsideKeywordIfNonEmptySpan() As Task
+            Await TestMissingAsync(
+"
+''' TKey must implement the System.IDisposable int[|erf|]ace
+class C(Of TKey)
+end class")
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)>
+        Public Async Function TestStartOfFullyQualifiedTypeName_Start() As Task
+            Await TestInRegularAndScriptAsync(
+"
+''' TKey must implement the [||]System.IDisposable interface.
+class C(Of TKey)
+end class",
+"
+''' TKey must implement the <see cref=""System.IDisposable""/> interface.
+class C(Of TKey)
+end class")
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)>
+        Public Async Function TestStartOfFullyQualifiedTypeName_Mid1() As Task
+            Await TestInRegularAndScriptAsync(
+"
+''' TKey must implement the System[||].IDisposable interface.
+class C(Of TKey)
+end class",
+"
+''' TKey must implement the <see cref=""System.IDisposable""/> interface.
+class C(Of TKey)
+end class")
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)>
+        Public Async Function TestStartOfFullyQualifiedTypeName_Mid2() As Task
+            Await TestInRegularAndScriptAsync(
+"
+''' TKey must implement the System.[||]IDisposable interface.
+class C(Of TKey)
+end class",
+"
+''' TKey must implement the <see cref=""System.IDisposable""/> interface.
+class C(Of TKey)
+end class")
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)>
+        Public Async Function TestStartOfFullyQualifiedTypeName_End() As Task
+            Await TestInRegularAndScriptAsync(
+"
+''' TKey must implement the System.IDisposable[||] interface.
+class C(Of TKey)
+end class",
+"
+''' TKey must implement the <see cref=""System.IDisposable""/> interface.
+class C(Of TKey)
+end class")
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)>
+        Public Async Function TestStartOfFullyQualifiedTypeName_CaseInsensitive() As Task
+            Await TestInRegularAndScriptAsync(
+"
+''' TKey must implement the [||]system.idisposable interface.
+class C(Of TKey)
+end class",
+"
+''' TKey must implement the <see cref=""system.idisposable""/> interface.
+class C(Of TKey)
+end class")
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)>
+        Public Async Function TestStartOfFullyQualifiedTypeName_Selected() As Task
+            Await TestInRegularAndScriptAsync(
+"
+''' TKey must implement the [|System.IDisposable|] interface.
+class C(Of TKey)
+end class",
+"
+''' TKey must implement the <see cref=""System.IDisposable""/> interface.
+class C(Of TKey)
+end class")
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)>
+        Public Async Function TestTypeParameterReference() As Task
+            Await TestInRegularAndScriptAsync(
+"
+''' [||]TKey must implement the System.IDisposable interface.
+class C(Of TKey)
+end class",
+"
+''' <typeparamref name=""TKey""/> must implement the System.IDisposable interface.
+class C(Of TKey)
+end class")
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)>
+        Public Async Function TestCanSeeInnerMethod() As Task
+            Await TestInRegularAndScriptAsync(
+"
+''' Use WriteLine[||] as a Console.WriteLine replacement
+class C
+    sub WriteLine(Of TKey)(value as TKey)
+    end sub
+end class",
+"
+''' Use <see cref=""WriteLine""/> as a Console.WriteLine replacement
+class C
+    sub WriteLine(Of TKey)(value as TKey)
+    end sub
+end class")
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)>
+        Public Async Function TestNotOnMispelledName() As Task
+            Await TestMissingAsync(
+"
+''' Use WriteLine1[||] as a Console.WriteLine replacement
+class C
+    sub WriteLine(Of TKey)(value as TKey)
+    end sub
+end class")
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)>
+        Public Async Function TestMethodTypeParameterSymbol() As Task
+            Await TestInRegularAndScriptAsync(
+"
+class C
+    ''' value has type TKey[||] so we don't box primitives.
+    sub WriteLine(Of TKey)(value as TKey)
+    end sub
+end class",
+"
+class C
+    ''' value has type <typeparamref name=""TKey""/> so we don't box primitives.
+    sub WriteLine(Of TKey)(value as TKey)
+    end sub
+end class")
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)>
+        Public Async Function TestMethodTypeParameterSymbol_CaseInsensitive() As Task
+            Await TestInRegularAndScriptAsync(
+"
+class C
+    ''' value has type TKey[||] so we don't box primitives.
+    sub WriteLine(Of tkey)(value as TKey)
+    end sub
+end class",
+"
+class C
+    ''' value has type <typeparamref name=""TKey""/> so we don't box primitives.
+    sub WriteLine(Of tkey)(value as TKey)
+    end sub
+end class")
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)>
+        Public Async Function TestMethodTypeParameterSymbol_EmptyBody() As Task
+            Await TestInRegularAndScriptAsync(
+"
+interface I
+    ''' value has type TKey[||] so we don't box primitives.
+    sub WriteLine(Of TKey)(value as TKey)
+end interface",
+"
+interface I
+    ''' value has type <typeparamref name=""TKey""/> so we don't box primitives.
+    sub WriteLine(Of TKey)(value as TKey)
+end interface")
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)>
+        Public Async Function TestMethodParameterSymbol() As Task
+            Await TestInRegularAndScriptAsync(
+"
+class C
+    ''' value[||] has type TKey so we don't box primitives.
+    sub WriteLine(Of TKey)(value as TKey)
+    end sub
+end class",
+"
+class C
+    ''' <paramref name=""value""/> has type TKey so we don't box primitives.
+    sub WriteLine(Of TKey)(value as TKey)
+    end sub
+end class")
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)>
+        Public Async Function TestMethodParameterSymbol_CaseInsensitive() As Task
+            Await TestInRegularAndScriptAsync(
+"
+class C
+    ''' value[||] has type TKey so we don't box primitives.
+    sub WriteLine(Of TKey)(Value as TKey)
+    end sub
+end class",
+"
+class C
+    ''' <paramref name=""value""/> has type TKey so we don't box primitives.
+    sub WriteLine(Of TKey)(Value as TKey)
+    end sub
+end class")
+        End Function
+
+        <Fact, Trait(Traits.Feature, Traits.Features.CodeActionsReplaceDocCommentTextWithTag)>
+        Public Async Function TestMethodParameterSymbol_EmptyBody() As Task
+            Await TestInRegularAndScriptAsync(
+"
+interface I
+    ''' value[||] has type TKey so we don't box primitives.
+    sub WriteLine(Of TKey)(value as TKey)
+end interface",
+"
+interface I
+    ''' <paramref name=""value""/> has type TKey so we don't box primitives.
+    sub WriteLine(Of TKey)(value as TKey)
+end interface")
+        End Function
+    End Class
+End Namespace
diff --git a/src/Features/CSharp/Portable/ReplaceDocCommentTextWithTag/CSharpReplaceDocCommentTextWithTagCodeRefactoringProvider.cs b/src/Features/CSharp/Portable/ReplaceDocCommentTextWithTag/CSharpReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
index 60b5cfa758983..486375fac176c 100644
--- a/src/Features/CSharp/Portable/ReplaceDocCommentTextWithTag/CSharpReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
+++ b/src/Features/CSharp/Portable/ReplaceDocCommentTextWithTag/CSharpReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
@@ -9,7 +9,7 @@ namespace Microsoft.CodeAnalysis.CSharp.ReplaceDocCommentTextWithTag
 {
     [ExportCodeRefactoringProvider(LanguageNames.CSharp), Shared]
     internal class CSharpReplaceDocCommentTextWithTagCodeRefactoringProvider :
-        AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider<MemberDeclarationSyntax>
+        AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider
     {
         protected override bool IsXmlTextToken(SyntaxToken token)
             => token.Kind() == SyntaxKind.XmlTextLiteralToken ||
diff --git a/src/Features/Core/Portable/ReplaceDocCommentTextWithTag/AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider.cs b/src/Features/Core/Portable/ReplaceDocCommentTextWithTag/AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
index 91dbb0bcc33ea..2e9a7bb4a6737 100644
--- a/src/Features/Core/Portable/ReplaceDocCommentTextWithTag/AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
+++ b/src/Features/Core/Portable/ReplaceDocCommentTextWithTag/AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
@@ -13,9 +13,7 @@
 
 namespace Microsoft.CodeAnalysis.ReplaceDocCommentTextWithTag
 {
-    internal abstract class AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider<TMemberDeclarationSyntax>
-        : CodeRefactoringProvider
-        where TMemberDeclarationSyntax : SyntaxNode
+    internal abstract class AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider : CodeRefactoringProvider
     {
         protected abstract bool IsAnyKeyword(string text);
         protected abstract bool IsXmlTextToken(SyntaxToken token);
diff --git a/src/Features/VisualBasic/Portable/ReplaceDocCommentTextWithTag/VisualBasicReplaceDocCommentTextWithTagCodeRefactoringProvider.vb b/src/Features/VisualBasic/Portable/ReplaceDocCommentTextWithTag/VisualBasicReplaceDocCommentTextWithTagCodeRefactoringProvider.vb
new file mode 100644
index 0000000000000..d4a8285b5524e
--- /dev/null
+++ b/src/Features/VisualBasic/Portable/ReplaceDocCommentTextWithTag/VisualBasicReplaceDocCommentTextWithTagCodeRefactoringProvider.vb
@@ -0,0 +1,26 @@
+' Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+Imports System.Composition
+Imports Microsoft.CodeAnalysis.CodeRefactorings
+Imports Microsoft.CodeAnalysis.ReplaceDocCommentTextWithTag
+
+Namespace Microsoft.CodeAnalysis.VisualBasic.ReplaceDocCommentTextWithTag
+    <ExportCodeRefactoringProvider(LanguageNames.VisualBasic), [Shared]>
+    Friend Class VisualBasicReplaceDocCommentTextWithTagCodeRefactoringProvider
+        Inherits AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider
+
+        Protected Overrides Function IsXmlTextToken(token As SyntaxToken) As Boolean
+            Return token.Kind() = SyntaxKind.XmlTextLiteralToken OrElse
+                   token.Kind() = SyntaxKind.DocumentationCommentLineBreakToken
+        End Function
+
+        Protected Overrides Function IsAnyKeyword(text As String) As Boolean
+            Return SyntaxFacts.GetKeywordKind(text) <> SyntaxKind.None OrElse
+                   SyntaxFacts.GetContextualKeywordKind(text) <> SyntaxKind.None
+        End Function
+
+        Protected Overrides Function ParseExpression(text As String) As SyntaxNode
+            Return SyntaxFactory.ParseExpression(text)
+        End Function
+    End Class
+End Namespace

From 967dfe460f8350c6188692c3642599a356ba67fe Mon Sep 17 00:00:00 2001
From: CyrusNajmabadi <cyrusn@microsoft.com>
Date: Sat, 12 Aug 2017 18:20:48 -0700
Subject: [PATCH 49/77] REmove commented out code.

---
 ...mmentTextWithTagCodeRefactoringProvider.cs | 23 -------------------
 1 file changed, 23 deletions(-)

diff --git a/src/Features/Core/Portable/ReplaceDocCommentTextWithTag/AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider.cs b/src/Features/Core/Portable/ReplaceDocCommentTextWithTag/AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
index 2e9a7bb4a6737..970efc775c619 100644
--- a/src/Features/Core/Portable/ReplaceDocCommentTextWithTag/AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
+++ b/src/Features/Core/Portable/ReplaceDocCommentTextWithTag/AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
@@ -147,29 +147,6 @@ private ISymbol GetEnclosingSymbol(SemanticModel semanticModel, int position, Ca
                 c => ReplaceTextAsync(context.Document, expandedSpan, replacement, c)));
         }
 
-        //private bool TryMatchTextAsSymbol(
-        //    CodeRefactoringContext context, TextSpan expandedSpan, 
-        //    string text, SemanticModel semanticModel, 
-        //    int speculativePosition, SpeculativeBindingOption binding)
-        //{
-        //    var parsed = ParseExpression(text);
-
-        //    var symbolInfo = semanticModel.GetSpeculativeSymbolInfo(speculativePosition, parsed, binding);
-        //    switch (symbolInfo.GetAnySymbol())
-        //    {
-        //        case IParameterSymbol parameter:
-                    
-        //            return true;
-        //        case ITypeParameterSymbol typeParameter:
-        //            return true;
-        //        case ISymbol symbol:
-        //            RegisterRefactoring(context, expandedSpan, $@"<see cref=""{text}""/>");
-        //            return true;
-        //        default:
-        //            return false;
-        //    }
-        //}
-
         private async Task<Document> ReplaceTextAsync(
             Document document, TextSpan span, string replacement, CancellationToken cancellationToken)
         {

From 2c64cf285ba3e5eac95ad8f9a6ce88dc6f6816ab Mon Sep 17 00:00:00 2001
From: Ashley Hauck <ashauck@microsoft.com>
Date: Mon, 14 Aug 2017 08:05:44 -0700
Subject: [PATCH 50/77] Update message of ERR_DynamicLocalFunctionTypeParameter

---
 src/Compilers/CSharp/Portable/CSharpResources.Designer.cs | 2 +-
 src/Compilers/CSharp/Portable/CSharpResources.resx        | 2 +-
 .../CSharp/Test/Emit/CodeGen/CodeGenLocalFunctionTests.cs | 2 +-
 .../CSharp/Test/Semantic/Semantics/LocalFunctionTests.cs  | 8 +++++++-
 4 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/src/Compilers/CSharp/Portable/CSharpResources.Designer.cs b/src/Compilers/CSharp/Portable/CSharpResources.Designer.cs
index 47edeb0810dd8..abcec9de9c30a 100644
--- a/src/Compilers/CSharp/Portable/CSharpResources.Designer.cs
+++ b/src/Compilers/CSharp/Portable/CSharpResources.Designer.cs
@@ -3725,7 +3725,7 @@ internal class CSharpResources {
         }
         
         /// <summary>
-        ///   Looks up a localized string similar to Cannot pass argument with dynamic type to generic local function &apos;{0}&apos;. Try specifying the type arguments explicitly..
+        ///   Looks up a localized string similar to Cannot pass argument with dynamic type to generic local function &apos;{0}&apos; with inferred type arguments..
         /// </summary>
         internal static string ERR_DynamicLocalFunctionTypeParameter {
             get {
diff --git a/src/Compilers/CSharp/Portable/CSharpResources.resx b/src/Compilers/CSharp/Portable/CSharpResources.resx
index 2023491b3a815..8058afdb4a243 100644
--- a/src/Compilers/CSharp/Portable/CSharpResources.resx
+++ b/src/Compilers/CSharp/Portable/CSharpResources.resx
@@ -5109,6 +5109,6 @@ To remove the warning, you can use /reference instead (set the Embed Interop Typ
     <value>Unable to read debug information of method '{0}' (token 0x{1:X8}) from assembly '{2}'</value>
   </data>
   <data name="ERR_DynamicLocalFunctionTypeParameter" xml:space="preserve">
-    <value>Cannot pass argument with dynamic type to generic local function '{0}'. Try specifying the type arguments explicitly.</value>
+    <value>Cannot pass argument with dynamic type to generic local function '{0}' with inferred type arguments.</value>
   </data>
 </root>
\ No newline at end of file
diff --git a/src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenLocalFunctionTests.cs b/src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenLocalFunctionTests.cs
index a750713147d1c..c60ca0e65dd38 100644
--- a/src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenLocalFunctionTests.cs
+++ b/src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenLocalFunctionTests.cs
@@ -3462,7 +3462,7 @@ void L1<T>(T x)
 L1<dynamic>(4);
 
 void L2<T>(int x, T y) => Console.WriteLine($""{x}, {y}: {typeof(T)}"");
-L2<double>(val, 3.0f);
+L2<float>(val, 3.0f);
 
 List<dynamic> listOfDynamic = new List<dynamic> { 1, 2, 3 };
 void L3<T>(List<T> x) => Console.WriteLine($""{string.Join("", "", x)}: {typeof(T)}"");
diff --git a/src/Compilers/CSharp/Test/Semantic/Semantics/LocalFunctionTests.cs b/src/Compilers/CSharp/Test/Semantic/Semantics/LocalFunctionTests.cs
index 953efa4677a9b..d2890d43c4a32 100644
--- a/src/Compilers/CSharp/Test/Semantic/Semantics/LocalFunctionTests.cs
+++ b/src/Compilers/CSharp/Test/Semantic/Semantics/LocalFunctionTests.cs
@@ -3136,7 +3136,10 @@ static void M()
             comp.VerifyEmitDiagnostics(
                 // (8,18): error CS1977: Cannot use a lambda expression as an argument to a dynamically dispatched operation without first casting it to a delegate or expression tree type.
                 //         L(m => L(d => d, m), null);
-                Diagnostic(ErrorCode.ERR_BadDynamicMethodArgLambda, "d => d").WithLocation(8, 18));
+                Diagnostic(ErrorCode.ERR_BadDynamicMethodArgLambda, "d => d").WithLocation(8, 18),
+                // (8,16): error CS8322: Cannot pass argument with dynamic type to generic local function 'L' with inferred type arguments.
+                //         L(m => L(d => d, m), null);
+                Diagnostic(ErrorCode.ERR_DynamicLocalFunctionTypeParameter, "L(d => d, m)").WithArguments("L").WithLocation(8, 16));
         }
 
         [Fact]
@@ -3159,6 +3162,9 @@ async Task<dynamic> L<T>(Func<dynamic, T> t, object p)
                 // (8,37): error CS1977: Cannot use a lambda expression as an argument to a dynamically dispatched operation without first casting it to a delegate or expression tree type.
                 //             => await L(async m => L(async d => await d, m), p);
                 Diagnostic(ErrorCode.ERR_BadDynamicMethodArgLambda, "async d => await d").WithLocation(8, 37),
+                // (8,35): error CS8322: Cannot pass argument with dynamic type to generic local function 'L' with inferred type arguments.
+                //             => await L(async m => L(async d => await d, m), p);
+                Diagnostic(ErrorCode.ERR_DynamicLocalFunctionTypeParameter, "L(async d => await d, m)").WithArguments("L").WithLocation(8, 35),
                 // (8,32): warning CS1998: This async method lacks 'await' operators and will run synchronously. Consider using the 'await' operator to await non-blocking API calls, or 'await Task.Run(...)' to do CPU-bound work on a background thread.
                 //             => await L(async m => L(async d => await d, m), p);
                 Diagnostic(ErrorCode.WRN_AsyncLacksAwaits, "=>").WithLocation(8, 32));

From a01f97916e645f036a24d29280167f8b8bc48a3f Mon Sep 17 00:00:00 2001
From: Jared Parsons <jaredpar@microsoft.com>
Date: Mon, 14 Aug 2017 09:45:13 -0700
Subject: [PATCH 51/77] Move to GitLink 3.0.0

---
 build/Targets/Packages.props | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/build/Targets/Packages.props b/build/Targets/Packages.props
index f841540c25a51..0931aa76fed12 100644
--- a/build/Targets/Packages.props
+++ b/build/Targets/Packages.props
@@ -8,7 +8,7 @@
     <EnvDTEVersion>8.0.1</EnvDTEVersion>
     <EnvDTE80Version>8.0.0</EnvDTE80Version>
     <FakeSignVersion>0.9.2</FakeSignVersion>
-    <GitLinkVersion>3.0.0-unstable0090</GitLinkVersion>
+    <GitLinkVersion>3.0.0</GitLinkVersion>
     <LibGit2SharpVersion>0.22.0</LibGit2SharpVersion>
     <MicroBuildCoreVersion>0.2.0</MicroBuildCoreVersion>
     <MicroBuildCoreSentinelVersion>1.0.0</MicroBuildCoreSentinelVersion>

From ec42cca95ab9c55769a30bcbfd3ed30aa1681ff5 Mon Sep 17 00:00:00 2001
From: Fredric Silberberg <frsilb@microsoft.com>
Date: Mon, 14 Aug 2017 11:34:00 -0700
Subject: [PATCH 52/77] Refactor missed internal field.

---
 .../Core/Portable/Generated/Operations.xml.Generated.cs     | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/Compilers/Core/Portable/Generated/Operations.xml.Generated.cs b/src/Compilers/Core/Portable/Generated/Operations.xml.Generated.cs
index e7c90f46bb3e6..1f201b8474331 100644
--- a/src/Compilers/Core/Portable/Generated/Operations.xml.Generated.cs
+++ b/src/Compilers/Core/Portable/Generated/Operations.xml.Generated.cs
@@ -2910,16 +2910,16 @@ internal sealed partial class LockStatement : BaseLockStatement, ILockStatement
     /// </summary>
     internal sealed partial class LazyLockStatement : BaseLockStatement, ILockStatement
     {
-        private readonly Lazy<IOperation> _lazyLockedObject;
+        private readonly Lazy<IOperation> _lazyExpression;
         private readonly Lazy<IOperation> _lazyBody;
 
         public LazyLockStatement(Lazy<IOperation> lockedObject, Lazy<IOperation> body, SemanticModel semanticModel, SyntaxNode syntax, ITypeSymbol type, Optional<object> constantValue) : base(semanticModel, syntax, type, constantValue)
         {
-            _lazyLockedObject = lockedObject ?? throw new System.ArgumentNullException(nameof(lockedObject));
+            _lazyExpression = lockedObject ?? throw new System.ArgumentNullException(nameof(lockedObject));
             _lazyBody = body ?? throw new System.ArgumentNullException(nameof(body));
         }
 
-        protected override IOperation ExpressionImpl => _lazyLockedObject.Value;
+        protected override IOperation ExpressionImpl => _lazyExpression.Value;
 
         protected override IOperation BodyImpl => _lazyBody.Value;
     }

From 558737922223dd02144dcb37aa4993e90f9ad1a8 Mon Sep 17 00:00:00 2001
From: Fredric Silberberg <frsilb@microsoft.com>
Date: Mon, 14 Aug 2017 18:27:00 -0700
Subject: [PATCH 53/77] Added ILockStatement tests.

---
 .../IOperationTests_ILockStatement.cs         | 347 ++++++++++++++++++
 .../IOperationTests_ILockStatement.vb         | 335 +++++++++++++++++
 2 files changed, 682 insertions(+)
 create mode 100644 src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_ILockStatement.cs
 create mode 100644 src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_ILockStatement.vb

diff --git a/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_ILockStatement.cs b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_ILockStatement.cs
new file mode 100644
index 0000000000000..9495e676c4831
--- /dev/null
+++ b/src/Compilers/CSharp/Test/Semantic/IOperation/IOperationTests_ILockStatement.cs
@@ -0,0 +1,347 @@
+// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Test.Utilities;
+using Xunit;
+
+namespace Microsoft.CodeAnalysis.CSharp.UnitTests
+{
+    public partial class IOperationTests : SemanticModelTestBase
+    {
+        [CompilerTrait(CompilerFeature.IOperation)]
+        [Fact]
+        public void ILockStatement_ObjectLock_FieldReference()
+        {
+            string source = @"
+public class C1
+{
+    object o = new object();
+
+    public void M()
+    {
+        /*<bind>*/lock (o)
+        {
+        }/*</bind>*/
+    }
+}
+";
+            string expectedOperationTree = @"
+ILockStatement (OperationKind.LockStatement) (Syntax: 'lock (o) ... }')
+  Expression: IFieldReferenceExpression: System.Object C1.o (OperationKind.FieldReferenceExpression, Type: System.Object) (Syntax: 'o')
+      Instance Receiver: IInstanceReferenceExpression (InstanceReferenceKind.Implicit) (OperationKind.InstanceReferenceExpression, Type: C1) (Syntax: 'o')
+  Body: IBlockStatement (0 statements) (OperationKind.BlockStatement) (Syntax: '{ ... }')
+";
+            var expectedDiagnostics = DiagnosticDescription.None;
+
+            VerifyOperationTreeAndDiagnosticsForTest<LockStatementSyntax>(source, expectedOperationTree, expectedDiagnostics);
+        }
+
+        [CompilerTrait(CompilerFeature.IOperation)]
+        [Fact]
+        public void ILockStatement_ObjectLock_LocalReference()
+        {
+            string source = @"
+public class C1
+{
+    public void M()
+    {
+        object o = new object();
+        /*<bind>*/lock (o)
+        {
+        }/*</bind>*/
+    }
+}
+";
+            string expectedOperationTree = @"
+ILockStatement (OperationKind.LockStatement) (Syntax: 'lock (o) ... }')
+  Expression: ILocalReferenceExpression: o (OperationKind.LocalReferenceExpression, Type: System.Object) (Syntax: 'o')
+  Body: IBlockStatement (0 statements) (OperationKind.BlockStatement) (Syntax: '{ ... }')
+";
+            var expectedDiagnostics = DiagnosticDescription.None;
+
+            VerifyOperationTreeAndDiagnosticsForTest<LockStatementSyntax>(source, expectedOperationTree, expectedDiagnostics);
+        }
+
+        [CompilerTrait(CompilerFeature.IOperation)]
+        [Fact]
+        public void ILockStatement_ObjectLock_Null()
+        {
+            string source = @"
+public class C1
+{
+    public void M()
+    {
+        /*<bind>*/lock (null)
+        {
+        }/*</bind>*/
+    }
+}
+";
+            string expectedOperationTree = @"
+ILockStatement (OperationKind.LockStatement) (Syntax: 'lock (null) ... }')
+  Expression: ILiteralExpression (Text: null) (OperationKind.LiteralExpression, Type: null, Constant: null) (Syntax: 'null')
+  Body: IBlockStatement (0 statements) (OperationKind.BlockStatement) (Syntax: '{ ... }')
+";
+            var expectedDiagnostics = DiagnosticDescription.None;
+
+            VerifyOperationTreeAndDiagnosticsForTest<LockStatementSyntax>(source, expectedOperationTree, expectedDiagnostics);
+        }
+
+        [CompilerTrait(CompilerFeature.IOperation)]
+        [Fact]
+        public void ILockStatement_ObjectLock_NonReferenceType()
+        {
+            string source = @"
+public class C1
+{
+    public void M()
+    {
+        int i = 1;
+        /*<bind>*/lock (i)
+        {
+        }/*</bind>*/
+    }
+}
+";
+            string expectedOperationTree = @"
+ILockStatement (OperationKind.LockStatement, IsInvalid) (Syntax: 'lock (i) ... }')
+  Expression: ILocalReferenceExpression: i (OperationKind.LocalReferenceExpression, Type: System.Int32, IsInvalid) (Syntax: 'i')
+  Body: IBlockStatement (0 statements) (OperationKind.BlockStatement) (Syntax: '{ ... }')
+";
+            var expectedDiagnostics = new DiagnosticDescription[] {
+                // CS0185: 'int' is not a reference type as required by the lock statement
+                //         /*<bind>*/lock (i)
+                Diagnostic(ErrorCode.ERR_LockNeedsReference, "i").WithArguments("int").WithLocation(7, 25)
+            };
+
+            VerifyOperationTreeAndDiagnosticsForTest<LockStatementSyntax>(source, expectedOperationTree, expectedDiagnostics);
+        }
+
+        [CompilerTrait(CompilerFeature.IOperation)]
+        [Fact]
+        public void ILockStatement_MissingLockExpression()
+        {
+            string source = @"
+public class C1
+{
+    public void M()
+    {
+        /*<bind>*/lock ()
+        {
+        }/*</bind>*/
+    }
+}
+";
+            string expectedOperationTree = @"
+ILockStatement (OperationKind.LockStatement, IsInvalid) (Syntax: 'lock () ... }')
+  Expression: IInvalidExpression (OperationKind.InvalidExpression, Type: ?, IsInvalid) (Syntax: '')
+      Children(0)
+  Body: IBlockStatement (0 statements) (OperationKind.BlockStatement) (Syntax: '{ ... }')
+";
+            var expectedDiagnostics = new DiagnosticDescription[] {
+                // CS1525: Invalid expression term ')'
+                //         /*<bind>*/lock ()
+                Diagnostic(ErrorCode.ERR_InvalidExprTerm, ")").WithArguments(")").WithLocation(6, 25)
+            };
+
+            VerifyOperationTreeAndDiagnosticsForTest<LockStatementSyntax>(source, expectedOperationTree, expectedDiagnostics);
+        }
+
+        [CompilerTrait(CompilerFeature.IOperation)]
+        [Fact]
+        public void ILockStatement_InvalidLockStatement()
+        {
+            string source = @"
+using System;
+
+public class C1
+{
+    public void M()
+    {
+        /*<bind>*/lock (invalidReference)
+        {
+        }/*</bind>*/
+    }
+}
+";
+            string expectedOperationTree = @"
+ILockStatement (OperationKind.LockStatement, IsInvalid) (Syntax: 'lock (inval ... }')
+  Expression: IInvalidExpression (OperationKind.InvalidExpression, Type: ?, IsInvalid) (Syntax: 'invalidReference')
+      Children(0)
+  Body: IBlockStatement (0 statements) (OperationKind.BlockStatement) (Syntax: '{ ... }')
+";
+            var expectedDiagnostics = new DiagnosticDescription[] {
+                // CS0103: The name 'invalidReference' does not exist in the current context
+                //         /*<bind>*/lock (invalidReference)
+                Diagnostic(ErrorCode.ERR_NameNotInContext, "invalidReference").WithArguments("invalidReference").WithLocation(8, 25)
+            };
+
+            VerifyOperationTreeAndDiagnosticsForTest<LockStatementSyntax>(source, expectedOperationTree, expectedDiagnostics);
+        }
+
+        [CompilerTrait(CompilerFeature.IOperation)]
+        [Fact]
+        public void ILockStatement_MissingBody()
+        {
+            string source = @"
+public class C1
+{
+    public void M()
+    {
+        object o = new object();
+        /*<bind>*/lock (o)
+/*</bind>*/    }
+}
+";
+            string expectedOperationTree = @"
+ILockStatement (OperationKind.LockStatement, IsInvalid) (Syntax: 'lock (o)
+')
+  Expression: ILocalReferenceExpression: o (OperationKind.LocalReferenceExpression, Type: System.Object) (Syntax: 'o')
+  Body: IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: '')
+      Expression: IInvalidExpression (OperationKind.InvalidExpression, Type: ?) (Syntax: '')
+          Children(0)
+";
+            var expectedDiagnostics = new DiagnosticDescription[] {
+                // CS1525: Invalid expression term '}'
+                //         /*<bind>*/lock (o)
+                Diagnostic(ErrorCode.ERR_InvalidExprTerm, "").WithArguments("}").WithLocation(7, 27),
+                // CS1002: ; expected
+                //         /*<bind>*/lock (o)
+                Diagnostic(ErrorCode.ERR_SemicolonExpected, "").WithLocation(7, 27)
+            };
+
+            VerifyOperationTreeAndDiagnosticsForTest<LockStatementSyntax>(source, expectedOperationTree, expectedDiagnostics);
+        }
+
+        [CompilerTrait(CompilerFeature.IOperation)]
+        [Fact]
+        public void ILockStatement_ExpressionLock_ObjectMethodCall()
+        {
+            string source = @"
+public class C1
+{
+    public void M()
+    {
+        object o = new object();
+        /*<bind>*/lock (o.ToString())
+        {
+        }/*</bind>*/
+    }
+}
+";
+            string expectedOperationTree = @"
+ILockStatement (OperationKind.LockStatement) (Syntax: 'lock (o.ToS ... }')
+  Expression: IInvocationExpression (virtual System.String System.Object.ToString()) (OperationKind.InvocationExpression, Type: System.String) (Syntax: 'o.ToString()')
+      Instance Receiver: ILocalReferenceExpression: o (OperationKind.LocalReferenceExpression, Type: System.Object) (Syntax: 'o')
+      Arguments(0)
+  Body: IBlockStatement (0 statements) (OperationKind.BlockStatement) (Syntax: '{ ... }')
+";
+            var expectedDiagnostics = DiagnosticDescription.None;
+
+            VerifyOperationTreeAndDiagnosticsForTest<LockStatementSyntax>(source, expectedOperationTree, expectedDiagnostics);
+        }
+
+        [CompilerTrait(CompilerFeature.IOperation)]
+        [Fact]
+        public void ILockStatement_ExpressionLock_ClassMethodCall()
+        {
+            string source = @"
+public class C1
+{
+    public void M()
+    {
+        /*<bind>*/lock (M2())
+        {
+        }/*</bind>*/
+    }
+
+    public object M2()
+    {
+        return new object();
+    }
+}
+";
+            string expectedOperationTree = @"
+ILockStatement (OperationKind.LockStatement) (Syntax: 'lock (M2()) ... }')
+  Expression: IInvocationExpression ( System.Object C1.M2()) (OperationKind.InvocationExpression, Type: System.Object) (Syntax: 'M2()')
+      Instance Receiver: IInstanceReferenceExpression (InstanceReferenceKind.Implicit) (OperationKind.InstanceReferenceExpression, Type: C1) (Syntax: 'M2')
+      Arguments(0)
+  Body: IBlockStatement (0 statements) (OperationKind.BlockStatement) (Syntax: '{ ... }')
+";
+            var expectedDiagnostics = DiagnosticDescription.None;
+
+            VerifyOperationTreeAndDiagnosticsForTest<LockStatementSyntax>(source, expectedOperationTree, expectedDiagnostics);
+        }
+
+        [CompilerTrait(CompilerFeature.IOperation)]
+        [Fact]
+        public void ILockStatement_ExpressionCall_VoidMethodCall()
+        {
+            string source = @"
+public class C1
+{
+    public void M()
+    {
+        /*<bind>*/lock (M2())
+        {
+        }/*</bind>*/
+    }
+
+    public void M2() { }
+}
+";
+            string expectedOperationTree = @"
+ILockStatement (OperationKind.LockStatement, IsInvalid) (Syntax: 'lock (M2()) ... }')
+  Expression: IInvocationExpression ( void C1.M2()) (OperationKind.InvocationExpression, Type: System.Void, IsInvalid) (Syntax: 'M2()')
+      Instance Receiver: IInstanceReferenceExpression (InstanceReferenceKind.Implicit) (OperationKind.InstanceReferenceExpression, Type: C1, IsInvalid) (Syntax: 'M2')
+      Arguments(0)
+  Body: IBlockStatement (0 statements) (OperationKind.BlockStatement) (Syntax: '{ ... }')
+";
+            var expectedDiagnostics = new DiagnosticDescription[] {
+                // CS0185: 'void' is not a reference type as required by the lock statement
+                //         /*<bind>*/lock (M2())
+                Diagnostic(ErrorCode.ERR_LockNeedsReference, "M2()").WithArguments("void").WithLocation(6, 25)
+            };
+
+            VerifyOperationTreeAndDiagnosticsForTest<LockStatementSyntax>(source, expectedOperationTree, expectedDiagnostics);
+        }
+
+        [CompilerTrait(CompilerFeature.IOperation)]
+        [Fact]
+        public void ILockStatement_NonEmptybody()
+        {
+            string source = @"
+using System;
+
+public class C1
+{
+    public void M()
+    {
+        /*<bind>*/lock (new object())
+        {
+            Console.WriteLine(""Hello World!"");
+        }/*</bind>*/
+    }
+}
+";
+            string expectedOperationTree = @"
+ILockStatement (OperationKind.LockStatement) (Syntax: 'lock (new o ... }')
+  Expression: IObjectCreationExpression (Constructor: System.Object..ctor()) (OperationKind.ObjectCreationExpression, Type: System.Object) (Syntax: 'new object()')
+      Arguments(0)
+      Initializer: null
+  Body: IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: '{ ... }')
+      IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'Console.Wri ... o World!"");')
+        Expression: IInvocationExpression (void System.Console.WriteLine(System.String value)) (OperationKind.InvocationExpression, Type: System.Void) (Syntax: 'Console.Wri ... lo World!"")')
+            Instance Receiver: null
+            Arguments(1):
+                IArgument (ArgumentKind.Explicit, Matching Parameter: value) (OperationKind.Argument) (Syntax: '""Hello World!""')
+                  ILiteralExpression (OperationKind.LiteralExpression, Type: System.String, Constant: ""Hello World!"") (Syntax: '""Hello World!""')
+                  InConversion: null
+                  OutConversion: null
+";
+            var expectedDiagnostics = DiagnosticDescription.None;
+
+            VerifyOperationTreeAndDiagnosticsForTest<LockStatementSyntax>(source, expectedOperationTree, expectedDiagnostics);
+        }
+    }
+}
diff --git a/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_ILockStatement.vb b/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_ILockStatement.vb
new file mode 100644
index 0000000000000..c27ffc8d030b4
--- /dev/null
+++ b/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_ILockStatement.vb
@@ -0,0 +1,335 @@
+' Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+Imports Microsoft.CodeAnalysis.Test.Utilities
+Imports Microsoft.CodeAnalysis.VisualBasic.Syntax
+
+Namespace Microsoft.CodeAnalysis.VisualBasic.UnitTests.Semantics
+    Partial Public Class IOperationTests
+        Inherits SemanticModelTestBase
+
+        <CompilerTrait(CompilerFeature.IOperation)>
+        <Fact()>
+        Public Sub ILockStatement_ObjectLock_FieldReference()
+            Dim source = <![CDATA[
+Option Strict On
+
+Public Class C1
+    Dim o As New Object
+    Public Sub M1()
+        SyncLock o'BIND:"SyncLock o"
+
+        End SyncLock
+    End Sub
+End Class]]>.Value
+
+            Dim expectedOperationTree = <![CDATA[
+ILockStatement (OperationKind.LockStatement) (Syntax: 'SyncLock o' ... nd SyncLock')
+  Expression: IFieldReferenceExpression: ConsoleApp2.C1.o As System.Object (OperationKind.FieldReferenceExpression, Type: System.Object) (Syntax: 'o')
+      Instance Receiver: IInstanceReferenceExpression (InstanceReferenceKind.Implicit) (OperationKind.InstanceReferenceExpression, Type: ConsoleApp2.C1) (Syntax: 'o')
+  Body: IBlockStatement (0 statements) (OperationKind.BlockStatement) (Syntax: 'SyncLock o' ... nd SyncLock')
+]]>.Value
+
+            Dim expectedDiagnostics = String.Empty
+
+            VerifyOperationTreeAndDiagnosticsForTest(Of SyncLockBlockSyntax)(source, expectedOperationTree, expectedDiagnostics)
+        End Sub
+
+        <CompilerTrait(CompilerFeature.IOperation)>
+        <Fact()>
+        Public Sub ILockStatement_ObjectLock_LocalReference()
+            Dim source = <![CDATA[
+Option Strict On
+
+Public Class C1
+    Public Sub M1()
+        Dim o As New Object
+        SyncLock o'BIND:"SyncLock o"
+
+        End SyncLock
+    End Sub
+End Class]]>.Value
+
+            Dim expectedOperationTree = <![CDATA[
+ILockStatement (OperationKind.LockStatement) (Syntax: 'SyncLock o' ... nd SyncLock')
+  Expression: ILocalReferenceExpression: o (OperationKind.LocalReferenceExpression, Type: System.Object) (Syntax: 'o')
+  Body: IBlockStatement (0 statements) (OperationKind.BlockStatement) (Syntax: 'SyncLock o' ... nd SyncLock')
+]]>.Value
+
+            Dim expectedDiagnostics = String.Empty
+
+            VerifyOperationTreeAndDiagnosticsForTest(Of SyncLockBlockSyntax)(source, expectedOperationTree, expectedDiagnostics)
+        End Sub
+
+        <CompilerTrait(CompilerFeature.IOperation)>
+        <Fact()>
+        Public Sub ILockStatement_ObjectLock_Nothing()
+            Dim source = <![CDATA[
+Option Strict On
+
+Public Class C1
+    Public Sub M1()
+        Dim o As New Object
+        SyncLock o'BIND:"SyncLock o"
+
+        End SyncLock
+    End Sub
+End Class]]>.Value
+
+            Dim expectedOperationTree = <![CDATA[
+ILockStatement (OperationKind.LockStatement) (Syntax: 'SyncLock o' ... nd SyncLock')
+  Expression: ILocalReferenceExpression: o (OperationKind.LocalReferenceExpression, Type: System.Object) (Syntax: 'o')
+  Body: IBlockStatement (0 statements) (OperationKind.BlockStatement) (Syntax: 'SyncLock o' ... nd SyncLock')
+]]>.Value
+
+            Dim expectedDiagnostics = String.Empty
+
+            VerifyOperationTreeAndDiagnosticsForTest(Of SyncLockBlockSyntax)(source, expectedOperationTree, expectedDiagnostics)
+        End Sub
+
+        <CompilerTrait(CompilerFeature.IOperation)>
+        <Fact()>
+        Public Sub ILockStatement_ObjectLock_NonReferenceType()
+            Dim source = <![CDATA[
+Option Strict On
+
+Public Class C1
+    Public Sub M1()
+        Dim i As Integer = 1
+        SyncLock i'BIND:"SyncLock i"
+
+        End SyncLock
+    End Sub
+End Class]]>.Value
+
+            Dim expectedOperationTree = <![CDATA[
+ILockStatement (OperationKind.LockStatement, IsInvalid) (Syntax: 'SyncLock i' ... nd SyncLock')
+  Expression: ILocalReferenceExpression: i (OperationKind.LocalReferenceExpression, Type: System.Int32, IsInvalid) (Syntax: 'i')
+  Body: IBlockStatement (0 statements) (OperationKind.BlockStatement, IsInvalid) (Syntax: 'SyncLock i' ... nd SyncLock')
+]]>.Value
+
+            Dim expectedDiagnostics = <![CDATA[
+BC30582: 'SyncLock' operand cannot be of type 'Integer' because 'Integer' is not a reference type.
+        SyncLock i'BIND:"SyncLock i"
+                                                                                          ~
+]]>.Value
+
+            VerifyOperationTreeAndDiagnosticsForTest(Of SyncLockBlockSyntax)(source, expectedOperationTree, expectedDiagnostics)
+        End Sub
+
+        <CompilerTrait(CompilerFeature.IOperation)>
+        <Fact()>
+        Public Sub ILockStatement_MissingLockExpression()
+            Dim source = <![CDATA[
+Option Strict On
+
+Public Class C1
+    Public Sub M1()
+        SyncLock'BIND:"SyncLock"
+
+        End SyncLock
+    End Sub
+End Class]]>.Value
+
+            Dim expectedOperationTree = <![CDATA[
+ILockStatement (OperationKind.LockStatement, IsInvalid) (Syntax: 'SyncLock'BI ... nd SyncLock')
+  Expression: IInvalidExpression (OperationKind.InvalidExpression, Type: ?, IsInvalid) (Syntax: '')
+      Children(0)
+  Body: IBlockStatement (0 statements) (OperationKind.BlockStatement, IsInvalid) (Syntax: 'SyncLock'BI ... nd SyncLock')
+]]>.Value
+
+            Dim expectedDiagnostics = <![CDATA[
+BC30201: Expression expected.
+        SyncLock'BIND:"SyncLock"
+                                                            ~
+]]>.Value
+
+            VerifyOperationTreeAndDiagnosticsForTest(Of SyncLockBlockSyntax)(source, expectedOperationTree, expectedDiagnostics)
+        End Sub
+
+        <CompilerTrait(CompilerFeature.IOperation)>
+        <Fact()>
+        Public Sub ILockStatement_InvalidLockExpression()
+            Dim source = <![CDATA[
+Option Strict On
+
+Public Class C1
+    Public Sub M1()
+        SyncLock InvalidReference'BIND:"SyncLock InvalidReference"
+
+        End SyncLock
+    End Sub
+End Class]]>.Value
+
+            Dim expectedOperationTree = <![CDATA[
+ILockStatement (OperationKind.LockStatement, IsInvalid) (Syntax: 'SyncLock In ... nd SyncLock')
+  Expression: IInvalidExpression (OperationKind.InvalidExpression, Type: ?, IsInvalid) (Syntax: 'InvalidReference')
+      Children(0)
+  Body: IBlockStatement (0 statements) (OperationKind.BlockStatement, IsInvalid) (Syntax: 'SyncLock In ... nd SyncLock')
+]]>.Value
+
+            Dim expectedDiagnostics = <![CDATA[
+BC30451: 'InvalidReference' is not declared. It may be inaccessible due to its protection level.
+        SyncLock InvalidReference'BIND:"SyncLock InvalidReference"
+                                                            ~~~~~~~
+]]>.Value
+
+            VerifyOperationTreeAndDiagnosticsForTest(Of SyncLockBlockSyntax)(source, expectedOperationTree, expectedDiagnostics)
+        End Sub
+
+        <CompilerTrait(CompilerFeature.IOperation)>
+        <Fact()>
+        Public Sub ILockExpression_MissingEndLock()
+            Dim source = <![CDATA[
+Option Strict On
+
+Public Class C1
+    Public Sub M1()
+        Dim o As New Object
+        SyncLock o'BIND:"SyncLock o"
+
+    End Sub
+End Class]]>.Value
+
+            Dim expectedOperationTree = <![CDATA[
+ILockStatement (OperationKind.LockStatement, IsInvalid) (Syntax: 'SyncLock o' ... SyncLock o"')
+  Expression: ILocalReferenceExpression: o (OperationKind.LocalReferenceExpression, Type: System.Object, IsInvalid) (Syntax: 'o')
+  Body: IBlockStatement (0 statements) (OperationKind.BlockStatement, IsInvalid) (Syntax: 'SyncLock o' ... SyncLock o"')
+]]>.Value
+
+            Dim expectedDiagnostics = <![CDATA[
+BC30675: 'SyncLock' statement must end with a matching 'End SyncLock'.
+        SyncLock o'BIND:"SyncLock o"
+                                                                                         ~
+]]>.Value
+
+            VerifyOperationTreeAndDiagnosticsForTest(Of SyncLockBlockSyntax)(source, expectedOperationTree, expectedDiagnostics)
+        End Sub
+
+        <CompilerTrait(CompilerFeature.IOperation)>
+        <Fact()>
+        Public Sub ILockStatement_ExpressionBody_ObjectCall()
+            Dim source = <![CDATA[
+Option Strict On
+
+Public Class C1
+    Public Sub M1()
+        Dim o As New Object
+        SyncLock o.ToString()'BIND:"SyncLock o.ToString()"
+        End SyncLock
+    End Sub
+End Class]]>.Value
+
+            Dim expectedOperationTree = <![CDATA[
+ILockStatement (OperationKind.LockStatement) (Syntax: 'SyncLock o. ... nd SyncLock')
+  Expression: IInvocationExpression (virtual Function System.Object.ToString() As System.String) (OperationKind.InvocationExpression, Type: System.String) (Syntax: 'o.ToString()')
+      Instance Receiver: ILocalReferenceExpression: o (OperationKind.LocalReferenceExpression, Type: System.Object) (Syntax: 'o')
+      Arguments(0)
+  Body: IBlockStatement (0 statements) (OperationKind.BlockStatement) (Syntax: 'SyncLock o. ... nd SyncLock')
+]]>.Value
+
+            Dim expectedDiagnostics = String.Empty
+
+            VerifyOperationTreeAndDiagnosticsForTest(Of SyncLockBlockSyntax)(source, expectedOperationTree, expectedDiagnostics)
+        End Sub
+
+        <CompilerTrait(CompilerFeature.IOperation)>
+        <Fact()>
+        Public Sub ILockStatement_ExpressionLock_ClassMethodCall()
+            Dim source = <![CDATA[
+Option Strict On
+
+Public Class C1
+    Public Sub M1()
+        SyncLock M2()'BIND:"SyncLock M2()"
+        End SyncLock
+    End Sub
+
+    Public Function M2() As Object
+        Return New Object
+    End Function
+End Class]]>.Value
+
+            Dim expectedOperationTree = <![CDATA[
+ILockStatement (OperationKind.LockStatement) (Syntax: 'SyncLock M2 ... nd SyncLock')
+  Expression: IInvocationExpression ( Function ConsoleApp2.C1.M2() As System.Object) (OperationKind.InvocationExpression, Type: System.Object) (Syntax: 'M2()')
+      Instance Receiver: IInstanceReferenceExpression (InstanceReferenceKind.Implicit) (OperationKind.InstanceReferenceExpression, Type: ConsoleApp2.C1) (Syntax: 'M2')
+      Arguments(0)
+  Body: IBlockStatement (0 statements) (OperationKind.BlockStatement) (Syntax: 'SyncLock M2 ... nd SyncLock')
+]]>.Value
+
+            Dim expectedDiagnostics = String.Empty
+
+            VerifyOperationTreeAndDiagnosticsForTest(Of SyncLockBlockSyntax)(source, expectedOperationTree, expectedDiagnostics)
+        End Sub
+
+        <CompilerTrait(CompilerFeature.IOperation)>
+        <Fact()>
+        Public Sub ILockStatement_ExpressionBody_SubMethod()
+            Dim source = <![CDATA[
+Option Strict On
+
+Public Class C1
+    Public Sub M1()
+        SyncLock M2()'BIND:"SyncLock M2()"
+        End SyncLock
+    End Sub
+
+    Public Sub M2()
+    End Sub
+End Class]]>.Value
+
+            Dim expectedOperationTree = <![CDATA[
+ILockStatement (OperationKind.LockStatement, IsInvalid) (Syntax: 'SyncLock M2 ... nd SyncLock')
+  Expression: IInvalidExpression (OperationKind.InvalidExpression, Type: ?, IsInvalid) (Syntax: 'M2()')
+      Children(1):
+          IInvocationExpression ( Sub ConsoleApp2.C1.M2()) (OperationKind.InvocationExpression, Type: System.Void, IsInvalid) (Syntax: 'M2()')
+            Instance Receiver: IInstanceReferenceExpression (InstanceReferenceKind.Implicit) (OperationKind.InstanceReferenceExpression, Type: ConsoleApp2.C1, IsInvalid) (Syntax: 'M2')
+            Arguments(0)
+  Body: IBlockStatement (0 statements) (OperationKind.BlockStatement, IsInvalid) (Syntax: 'SyncLock M2 ... nd SyncLock')
+]]>.Value
+
+            Dim expectedDiagnostics = <![CDATA[
+BC30491: Expression does not produce a value.
+        SyncLock M2()'BIND:"SyncLock M2()"
+                                                            ~
+]]>.Value
+
+            VerifyOperationTreeAndDiagnosticsForTest(Of SyncLockBlockSyntax)(source, expectedOperationTree, expectedDiagnostics)
+        End Sub
+
+        <CompilerTrait(CompilerFeature.IOperation)>
+        <Fact()>
+        Public Sub ILockStatement_NonEmptyBody()
+            Dim source = <![CDATA[
+Option Strict On
+Imports System
+
+Public Class C1
+    Public Sub M1()
+        Dim o As New Object
+        SyncLock o'BIND:"SyncLock o"
+            Console.WriteLine("Hello World!")
+        End SyncLock
+    End Sub
+End Class]]>.Value
+
+            Dim expectedOperationTree = <![CDATA[
+ILockStatement (OperationKind.LockStatement) (Syntax: 'SyncLock o' ... nd SyncLock')
+  Expression: ILocalReferenceExpression: o (OperationKind.LocalReferenceExpression, Type: System.Object) (Syntax: 'o')
+  Body: IBlockStatement (1 statements) (OperationKind.BlockStatement) (Syntax: 'SyncLock o' ... nd SyncLock')
+      IExpressionStatement (OperationKind.ExpressionStatement) (Syntax: 'Console.Wri ... lo World!")')
+        Expression: IInvocationExpression (Sub System.Console.WriteLine(value As System.String)) (OperationKind.InvocationExpression, Type: System.Void) (Syntax: 'Console.Wri ... lo World!")')
+            Instance Receiver: null
+            Arguments(1):
+                IArgument (ArgumentKind.Explicit, Matching Parameter: value) (OperationKind.Argument) (Syntax: '"Hello World!"')
+                  ILiteralExpression (OperationKind.LiteralExpression, Type: System.String, Constant: "Hello World!") (Syntax: '"Hello World!"')
+                  InConversion: null
+                  OutConversion: null
+]]>.Value
+
+            Dim expectedDiagnostics = String.Empty
+
+            VerifyOperationTreeAndDiagnosticsForTest(Of SyncLockBlockSyntax)(source, expectedOperationTree, expectedDiagnostics)
+        End Sub
+    End Class
+End Namespace

From 6f7e59307a53bddf4d24d0c80196a2b91a064d59 Mon Sep 17 00:00:00 2001
From: Fredric Silberberg <frsilb@microsoft.com>
Date: Mon, 14 Aug 2017 18:28:07 -0700
Subject: [PATCH 54/77] Fixed unintentional case change.

---
 .../Portable/Operations/VisualBasicOperationFactory.vb      | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb b/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
index f40710258a599..0e90cc1ce4ace 100644
--- a/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
+++ b/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
@@ -1073,7 +1073,7 @@ Namespace Microsoft.CodeAnalysis.Semantics
 
         Private Function CreateBoundGotoStatementOperation(boundGotoStatement As BoundGotoStatement) As IBranchStatement
             Dim target As ILabelSymbol = boundGotoStatement.Label
-            Dim branchKind As BranchKind = branchKind.GoTo
+            Dim branchKind As BranchKind = BranchKind.GoTo
             Dim syntax As SyntaxNode = boundGotoStatement.Syntax
             Dim type As ITypeSymbol = Nothing
             Dim constantValue As [Optional](Of Object) = New [Optional](Of Object)()
@@ -1083,7 +1083,7 @@ Namespace Microsoft.CodeAnalysis.Semantics
 
         Private Function CreateBoundContinueStatementOperation(boundContinueStatement As BoundContinueStatement) As IBranchStatement
             Dim target As ILabelSymbol = boundContinueStatement.Label
-            Dim branchKind As BranchKind = branchKind.Continue
+            Dim branchKind As BranchKind = BranchKind.Continue
             Dim syntax As SyntaxNode = boundContinueStatement.Syntax
             Dim type As ITypeSymbol = Nothing
             Dim constantValue As [Optional](Of Object) = New [Optional](Of Object)()
@@ -1093,7 +1093,7 @@ Namespace Microsoft.CodeAnalysis.Semantics
 
         Private Function CreateBoundExitStatementOperation(boundExitStatement As BoundExitStatement) As IBranchStatement
             Dim target As ILabelSymbol = boundExitStatement.Label
-            Dim branchKind As BranchKind = branchKind.Break
+            Dim branchKind As BranchKind = BranchKind.Break
             Dim syntax As SyntaxNode = boundExitStatement.Syntax
             Dim type As ITypeSymbol = Nothing
             Dim constantValue As [Optional](Of Object) = New [Optional](Of Object)()

From 95b3cca046f305d4bda9c0bce3255560e2a39fbf Mon Sep 17 00:00:00 2001
From: Fredric Silberberg <frsilb@microsoft.com>
Date: Mon, 14 Aug 2017 18:29:05 -0700
Subject: [PATCH 55/77] Fixed another unintential case change.

---
 .../Portable/Operations/VisualBasicOperationFactory.vb      | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb b/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
index 0e90cc1ce4ace..b29429d9f164c 100644
--- a/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
+++ b/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
@@ -286,7 +286,7 @@ Namespace Microsoft.CodeAnalysis.Semantics
         End Function
 
         Private Function CreateBoundMeReferenceOperation(boundMeReference As BoundMeReference) As IInstanceReferenceExpression
-            Dim instanceReferenceKind As InstanceReferenceKind = If(boundMeReference.WasCompilerGenerated, instanceReferenceKind.Implicit, instanceReferenceKind.Explicit)
+            Dim instanceReferenceKind As InstanceReferenceKind = If(boundMeReference.WasCompilerGenerated, InstanceReferenceKind.Implicit, InstanceReferenceKind.Explicit)
             Dim syntax As SyntaxNode = boundMeReference.Syntax
             Dim type As ITypeSymbol = boundMeReference.Type
             Dim constantValue As [Optional](Of Object) = ConvertToOptional(boundMeReference.ConstantValueOpt)
@@ -295,7 +295,7 @@ Namespace Microsoft.CodeAnalysis.Semantics
         End Function
 
         Private Function CreateBoundMyBaseReferenceOperation(boundMyBaseReference As BoundMyBaseReference) As IInstanceReferenceExpression
-            Dim instanceReferenceKind As InstanceReferenceKind = instanceReferenceKind.BaseClass
+            Dim instanceReferenceKind As InstanceReferenceKind = InstanceReferenceKind.BaseClass
             Dim syntax As SyntaxNode = boundMyBaseReference.Syntax
             Dim type As ITypeSymbol = boundMyBaseReference.Type
             Dim constantValue As [Optional](Of Object) = ConvertToOptional(boundMyBaseReference.ConstantValueOpt)
@@ -304,7 +304,7 @@ Namespace Microsoft.CodeAnalysis.Semantics
         End Function
 
         Private Function CreateBoundMyClassReferenceOperation(boundMyClassReference As BoundMyClassReference) As IInstanceReferenceExpression
-            Dim instanceReferenceKind As InstanceReferenceKind = instanceReferenceKind.ThisClass
+            Dim instanceReferenceKind As InstanceReferenceKind = InstanceReferenceKind.ThisClass
             Dim syntax As SyntaxNode = boundMyClassReference.Syntax
             Dim type As ITypeSymbol = boundMyClassReference.Type
             Dim constantValue As [Optional](Of Object) = ConvertToOptional(boundMyClassReference.ConstantValueOpt)

From e9b367da7dfcbd08d14a1dfcac35bd4e57a77d10 Mon Sep 17 00:00:00 2001
From: Ashley Hauck <ashauck@microsoft.com>
Date: Tue, 15 Aug 2017 08:13:52 -0700
Subject: [PATCH 56/77] Refactor comments in local function binder

---
 .../Portable/Binder/Binder_Invocation.cs      | 41 ++++++++++---------
 1 file changed, 21 insertions(+), 20 deletions(-)

diff --git a/src/Compilers/CSharp/Portable/Binder/Binder_Invocation.cs b/src/Compilers/CSharp/Portable/Binder/Binder_Invocation.cs
index 4489ab8a78346..86c6b9e1976f1 100644
--- a/src/Compilers/CSharp/Portable/Binder/Binder_Invocation.cs
+++ b/src/Compilers/CSharp/Portable/Binder/Binder_Invocation.cs
@@ -627,15 +627,12 @@ private static bool HasApplicableConditionalMethod(OverloadResolutionResult<Meth
             CSharpSyntaxNode queryClause,
             MethodGroupResolution resolution)
         {
-            // Invocations of local functions with dynamic arguments
-            // don't need to be dispatched as dynamic invocations
-            // since they cannot be overloaded.  Instead, we'll just
-            // emit a standard call with dynamic implicit conversions
-            // for any dynamic arguments. The one exception is params
-            // arguments which cannot be targeted by dynamic arguments
-            // because there is an ambiguity between an array target
-            // and the params element target. See
-            // https://github.com/dotnet/roslyn/issues/10708
+            // Invocations of local functions with dynamic arguments don't need
+            // to be dispatched as dynamic invocations since they cannot be
+            // overloaded. Instead, we'll just emit a standard call with
+            // dynamic implicit conversions for any dynamic arguments. There
+            // are two exceptions: "params", and unconstructed generics. See
+            // comments below for the exact semantics in these cases.
 
             Debug.Assert(resolution.IsLocalFunctionInvocation);
             Debug.Assert(resolution.OverloadResolutionResult.Succeeded);
@@ -650,9 +647,10 @@ private static bool HasApplicableConditionalMethod(OverloadResolutionResult<Meth
             var methodResult = validResult.Result;
 
             // We're only in trouble if a dynamic argument is passed to the
-            // params parameter and is ambiguous at compile time between
-            // normal and expanded form i.e., there is exactly one dynamic
-            // argument to a params parameter
+            // params parameter and is ambiguous at compile time between normal
+            // and expanded form i.e., there is exactly one dynamic argument to
+            // a params parameter
+            // See https://github.com/dotnet/roslyn/issues/10708
             if (OverloadResolution.IsValidParams(localFunction) &&
                 methodResult.Kind == MemberResolutionKind.ApplicableInNormalForm)
             {
@@ -682,14 +680,17 @@ private static bool HasApplicableConditionalMethod(OverloadResolutionResult<Meth
                 }
             }
 
-            // If we call an unconstructed generic local function with a dynamic argument in
-            // a place where it influences the type parameters, we need to dynamically dispatch the call
-            // (as the function must be constructed at runtime). We cannot do that, so disallow that.
-            // However, doing a specific analysis of each argument and its corresponding parameter
-            // to check if it's generic (and allow dynamic in non-generic parameters) may break
-            // overload resolution in the future, if we ever allow overloaded local functions.
-            // So, just disallow any mixing of dynamic and inferred generics.
-            // (Explicitly-provided generic arguments are fine)
+            // If we call an unconstructed generic local function with a
+            // dynamic argument in a place where it influences the type
+            // parameters, we need to dynamically dispatch the call (as the
+            // function must be constructed at runtime). We cannot do that, so
+            // disallow that. However, doing a specific analysis of each
+            // argument and its corresponding parameter to check if it's
+            // generic (and allow dynamic in non-generic parameters) may break
+            // overload resolution in the future, if we ever allow overloaded
+            // local functions. So, just disallow any mixing of dynamic and
+            // inferred generics. (Explicit generic arguments are fine)
+            // See https://github.com/dotnet/roslyn/issues/21317
             if (boundMethodGroup.TypeArgumentsOpt.IsDefaultOrEmpty && localFunction.IsGenericMethod)
             {
                 Error(diagnostics,

From 2eef211d0161eb9f39db45c0277b88ff4ba0142b Mon Sep 17 00:00:00 2001
From: Ashley Hauck <ashauck@microsoft.com>
Date: Tue, 15 Aug 2017 08:40:24 -0700
Subject: [PATCH 57/77] Add note that while we could implement dynamic
 invocations, we chose not to

---
 src/Compilers/CSharp/Portable/Binder/Binder_Invocation.cs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/Compilers/CSharp/Portable/Binder/Binder_Invocation.cs b/src/Compilers/CSharp/Portable/Binder/Binder_Invocation.cs
index 86c6b9e1976f1..9492de04d8f01 100644
--- a/src/Compilers/CSharp/Portable/Binder/Binder_Invocation.cs
+++ b/src/Compilers/CSharp/Portable/Binder/Binder_Invocation.cs
@@ -631,8 +631,10 @@ private static bool HasApplicableConditionalMethod(OverloadResolutionResult<Meth
             // to be dispatched as dynamic invocations since they cannot be
             // overloaded. Instead, we'll just emit a standard call with
             // dynamic implicit conversions for any dynamic arguments. There
-            // are two exceptions: "params", and unconstructed generics. See
-            // comments below for the exact semantics in these cases.
+            // are two exceptions: "params", and unconstructed generics. While
+            // implementing those cases with dynamic invocations is possible,
+            // we have decided the implementation complexity is not worth it.
+            // Refer to the comments below for the exact semantics.
 
             Debug.Assert(resolution.IsLocalFunctionInvocation);
             Debug.Assert(resolution.OverloadResolutionResult.Succeeded);

From b3eb0b670fa7ad5a8465b325fd7e118c740db05a Mon Sep 17 00:00:00 2001
From: Charles Stoner <chucks@microsoft.com>
Date: Tue, 15 Aug 2017 08:22:51 -0700
Subject: [PATCH 58/77] Use default tuple fields in conversion since fields
 from inferred names are marked not usable in C#7

---
 .../LocalRewriter/LocalRewriter_Conversion.cs | 10 +------
 ...writer_DeconstructionAssignmentOperator.cs | 13 +---------
 .../LocalRewriter/LocalRewriter_Field.cs      | 16 +++++++++++-
 .../Test/Emit/CodeGen/CodeGenTupleTest.cs     | 23 ++++++++++++++++
 .../Test/Emit/CodeGen/CodeGenTuples.vb        | 26 +++++++++++++++++--
 5 files changed, 64 insertions(+), 24 deletions(-)

diff --git a/src/Compilers/CSharp/Portable/Lowering/LocalRewriter/LocalRewriter_Conversion.cs b/src/Compilers/CSharp/Portable/Lowering/LocalRewriter/LocalRewriter_Conversion.cs
index 075e417394dde..89e9ed6096d24 100644
--- a/src/Compilers/CSharp/Portable/Lowering/LocalRewriter/LocalRewriter_Conversion.cs
+++ b/src/Compilers/CSharp/Portable/Lowering/LocalRewriter/LocalRewriter_Conversion.cs
@@ -650,16 +650,8 @@ private BoundExpression MakeImplicitConversion(BoundExpression rewrittenOperand,
 
             for (int i = 0; i < numElements; i++)
             {
-                var field = srcElementFields[i];
-
-                DiagnosticInfo useSiteInfo = field.GetUseSiteDiagnostic();
-                if ((object)useSiteInfo != null && useSiteInfo.Severity == DiagnosticSeverity.Error)
-                {
-                    Symbol.ReportUseSiteDiagnostic(useSiteInfo, _diagnostics, syntax.Location);
-                }
-                var fieldAccess = MakeTupleFieldAccess(syntax, field, savedTuple, null, LookupResultKind.Empty);
+                var fieldAccess = MakeTupleFieldAccessAndReportUseSiteDiagnostics(savedTuple, syntax, srcElementFields[i]);
                 var convertedFieldAccess = MakeConversionNode(syntax, fieldAccess, elementConversions[i], destElementTypes[i], @checked, explicitCastInCode);
-
                 fieldAccessorsBuilder.Add(convertedFieldAccess);
             }
 
diff --git a/src/Compilers/CSharp/Portable/Lowering/LocalRewriter/LocalRewriter_DeconstructionAssignmentOperator.cs b/src/Compilers/CSharp/Portable/Lowering/LocalRewriter/LocalRewriter_DeconstructionAssignmentOperator.cs
index 2265088d8a49e..a8ab8094cce5b 100644
--- a/src/Compilers/CSharp/Portable/Lowering/LocalRewriter/LocalRewriter_DeconstructionAssignmentOperator.cs
+++ b/src/Compilers/CSharp/Portable/Lowering/LocalRewriter/LocalRewriter_DeconstructionAssignmentOperator.cs
@@ -221,18 +221,7 @@ private static bool IsTupleExpression(BoundKind kind)
             var builder = ArrayBuilder<BoundExpression>.GetInstance(numElements);
             for (int i = 0; i < numElements; i++)
             {
-                var field = fields[i];
-
-                // Use default field rather than implicitly named fields since
-                // fields from inferred names are not usable in C# 7.0.
-                field = field.CorrespondingTupleField ?? field;
-
-                DiagnosticInfo useSiteInfo = field.GetUseSiteDiagnostic();
-                if ((object)useSiteInfo != null && useSiteInfo.Severity == DiagnosticSeverity.Error)
-                {
-                    Symbol.ReportUseSiteDiagnostic(useSiteInfo, _diagnostics, expression.Syntax.Location);
-                }
-                var fieldAccess = MakeTupleFieldAccess(expression.Syntax, field, tuple, null, LookupResultKind.Empty);
+                var fieldAccess = MakeTupleFieldAccessAndReportUseSiteDiagnostics(tuple, expression.Syntax, fields[i]);
                 builder.Add(fieldAccess);
             }
             return builder.ToImmutableAndFree();
diff --git a/src/Compilers/CSharp/Portable/Lowering/LocalRewriter/LocalRewriter_Field.cs b/src/Compilers/CSharp/Portable/Lowering/LocalRewriter/LocalRewriter_Field.cs
index 92942a3872be5..f178d2737224d 100644
--- a/src/Compilers/CSharp/Portable/Lowering/LocalRewriter/LocalRewriter_Field.cs
+++ b/src/Compilers/CSharp/Portable/Lowering/LocalRewriter/LocalRewriter_Field.cs
@@ -1,7 +1,6 @@
 // Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
 
 using Microsoft.CodeAnalysis.CSharp.Symbols;
-using System.Diagnostics;
 
 namespace Microsoft.CodeAnalysis.CSharp
 {
@@ -90,5 +89,20 @@ public override BoundNode VisitFieldAccess(BoundFieldAccess node)
             // make a field access for the most local access
             return _factory.Field(rewrittenReceiver, underlyingField);
         }
+
+        private BoundExpression MakeTupleFieldAccessAndReportUseSiteDiagnostics(BoundExpression tuple, SyntaxNode syntax, FieldSymbol field)
+        {
+            // Use default field rather than implicitly named fields since
+            // fields from inferred names are not usable in C# 7.0.
+            field = field.CorrespondingTupleField ?? field;
+
+            DiagnosticInfo useSiteInfo = field.GetUseSiteDiagnostic();
+            if ((object)useSiteInfo != null && useSiteInfo.Severity == DiagnosticSeverity.Error)
+            {
+                Symbol.ReportUseSiteDiagnostic(useSiteInfo, _diagnostics, syntax.Location);
+            }
+
+            return MakeTupleFieldAccess(syntax, field, tuple, null, LookupResultKind.Empty);
+        }
     }
 }
diff --git a/src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenTupleTest.cs b/src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenTupleTest.cs
index 76b8f3d52aa8f..197b78458000c 100644
--- a/src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenTupleTest.cs
+++ b/src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenTupleTest.cs
@@ -3938,6 +3938,29 @@ static class Extension
             verifier7_1.VerifyDiagnostics();
         }
 
+        [WorkItem(21518, "https://github.com/dotnet/roslyn/issues/21518")]
+        [Fact]
+        public void InferredName_Conversion()
+        {
+            var source =
+@"using System.Collections.Generic;
+class C
+{
+    static void F((int, IList<object>) items)
+    {
+    }
+    static void Test()
+    {
+        var items = new List<object>();
+        var group = (1, items);
+        F(group);
+    }
+}";
+            var comp = CreateCompilation(source, parseOptions: TestOptions.Regular.WithLanguageVersion(LanguageVersion.CSharp7),
+                references: new[] { MscorlibRef, ValueTupleRef, SystemRuntimeFacadeRef, SystemCoreRef });
+            comp.VerifyEmitDiagnostics();
+        }
+
         [Fact]
         public void LongTupleWithArgumentEvaluation()
         {
diff --git a/src/Compilers/VisualBasic/Test/Emit/CodeGen/CodeGenTuples.vb b/src/Compilers/VisualBasic/Test/Emit/CodeGen/CodeGenTuples.vb
index c31232399d2ff..361e61e4a8647 100644
--- a/src/Compilers/VisualBasic/Test/Emit/CodeGen/CodeGenTuples.vb
+++ b/src/Compilers/VisualBasic/Test/Emit/CodeGen/CodeGenTuples.vb
@@ -6277,6 +6277,28 @@ BC37289: Tuple element name 'M' is inferred. Please use language version 15.3 or
             verifier15_3.VerifyDiagnostics()
         End Sub
 
+        <Fact>
+        Public Sub InferredName_Conversion()
+            Dim source = <compilation>
+                             <file>
+Imports System.Collections.Generic
+Class C
+    Shared Sub F(items As (Integer, IList(Of Object)))
+    End Sub
+    Shared Sub Test()
+        Dim items = New List(Of Object)()
+        Dim group = (1, items)
+        F(group)
+    End Sub
+End Class
+    </file>
+                         </compilation>
+            Dim comp = CreateCompilationWithMscorlibAndVBRuntime(source,
+                additionalRefs:={ValueTupleRef, SystemRuntimeFacadeRef, SystemCoreRef},
+                parseOptions:=TestOptions.Regular.WithLanguageVersion(LanguageVersion.VisualBasic15))
+            comp.AssertTheseEmitDiagnostics(<errors/>)
+        End Sub
+
         <Fact>
         Public Sub LongTupleWithArgumentEvaluation()
 
@@ -7564,7 +7586,7 @@ BC36625: Lambda expression cannot be converted to 'Integer' because 'Integer' is
         End Sub
 
         <Fact>
-        Public Sub TupleInferredLambdStrictOn()
+        Public Sub TupleInferredLambdaStrictOn()
 
             Dim comp = CreateCompilationWithMscorlibAndVBRuntime(
 <compilation>
@@ -7600,7 +7622,7 @@ BC36642: Option Strict On requires each lambda expression parameter to be declar
         End Sub
 
         <Fact()>
-        Public Sub TupleInferredLambdStrictOff()
+        Public Sub TupleInferredLambdaStrictOff()
 
             Dim verifier = CompileAndVerify(
 <compilation>

From 75c45f1dc66f7ec6a56e26cddd303ecd4c420cff Mon Sep 17 00:00:00 2001
From: Fredric Silberberg <frsilb@microsoft.com>
Date: Tue, 15 Aug 2017 09:41:21 -0700
Subject: [PATCH 59/77] Fixed misgenerated tests.

---
 .../Operations/VisualBasicOperationFactory.vb |  2 +-
 .../IOperationTests_ILockStatement.vb         | 20 +++++++++----------
 2 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb b/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
index b29429d9f164c..4d78b7e775648 100644
--- a/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
+++ b/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
@@ -471,7 +471,7 @@ Namespace Microsoft.CodeAnalysis.Semantics
         End Function
 
         Private Function CreateBoundUserDefinedShortCircuitingOperatorOperation(boundUserDefinedShortCircuitingOperator As BoundUserDefinedShortCircuitingOperator) As IBinaryOperatorExpression
-            Dim binaryOperationKind As BinaryOperationKind = If((boundUserDefinedShortCircuitingOperator.BitwiseOperator.OperatorKind And BinaryOperatorKind.And) <> 0, binaryOperationKind.OperatorMethodConditionalAnd, binaryOperationKind.OperatorMethodConditionalOr)
+            Dim binaryOperationKind As BinaryOperationKind = If((boundUserDefinedShortCircuitingOperator.BitwiseOperator.OperatorKind And BinaryOperatorKind.And) <> 0, BinaryOperationKind.OperatorMethodConditionalAnd, BinaryOperationKind.OperatorMethodConditionalOr)
             Dim leftOperand As Lazy(Of IOperation) = New Lazy(Of IOperation)(Function() Create(boundUserDefinedShortCircuitingOperator.LeftOperand))
             Dim rightOperand As Lazy(Of IOperation) = New Lazy(Of IOperation)(Function() Create(boundUserDefinedShortCircuitingOperator.BitwiseOperator.Right))
             Dim usesOperatorMethod As Boolean = True
diff --git a/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_ILockStatement.vb b/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_ILockStatement.vb
index c27ffc8d030b4..41bb967e51dbc 100644
--- a/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_ILockStatement.vb
+++ b/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_ILockStatement.vb
@@ -24,8 +24,8 @@ End Class]]>.Value
 
             Dim expectedOperationTree = <![CDATA[
 ILockStatement (OperationKind.LockStatement) (Syntax: 'SyncLock o' ... nd SyncLock')
-  Expression: IFieldReferenceExpression: ConsoleApp2.C1.o As System.Object (OperationKind.FieldReferenceExpression, Type: System.Object) (Syntax: 'o')
-      Instance Receiver: IInstanceReferenceExpression (InstanceReferenceKind.Implicit) (OperationKind.InstanceReferenceExpression, Type: ConsoleApp2.C1) (Syntax: 'o')
+  Expression: IFieldReferenceExpression: C1.o As System.Object (OperationKind.FieldReferenceExpression, Type: System.Object) (Syntax: 'o')
+      Instance Receiver: IInstanceReferenceExpression (InstanceReferenceKind.Implicit) (OperationKind.InstanceReferenceExpression, Type: C1) (Syntax: 'o')
   Body: IBlockStatement (0 statements) (OperationKind.BlockStatement) (Syntax: 'SyncLock o' ... nd SyncLock')
 ]]>.Value
 
@@ -110,7 +110,7 @@ ILockStatement (OperationKind.LockStatement, IsInvalid) (Syntax: 'SyncLock i' ..
             Dim expectedDiagnostics = <![CDATA[
 BC30582: 'SyncLock' operand cannot be of type 'Integer' because 'Integer' is not a reference type.
         SyncLock i'BIND:"SyncLock i"
-                                                                                          ~
+                 ~
 ]]>.Value
 
             VerifyOperationTreeAndDiagnosticsForTest(Of SyncLockBlockSyntax)(source, expectedOperationTree, expectedDiagnostics)
@@ -140,7 +140,7 @@ ILockStatement (OperationKind.LockStatement, IsInvalid) (Syntax: 'SyncLock'BI ..
             Dim expectedDiagnostics = <![CDATA[
 BC30201: Expression expected.
         SyncLock'BIND:"SyncLock"
-                                                            ~
+                ~
 ]]>.Value
 
             VerifyOperationTreeAndDiagnosticsForTest(Of SyncLockBlockSyntax)(source, expectedOperationTree, expectedDiagnostics)
@@ -170,7 +170,7 @@ ILockStatement (OperationKind.LockStatement, IsInvalid) (Syntax: 'SyncLock In ..
             Dim expectedDiagnostics = <![CDATA[
 BC30451: 'InvalidReference' is not declared. It may be inaccessible due to its protection level.
         SyncLock InvalidReference'BIND:"SyncLock InvalidReference"
-                                                            ~~~~~~~
+                 ~~~~~~~~~~~~~~~~
 ]]>.Value
 
             VerifyOperationTreeAndDiagnosticsForTest(Of SyncLockBlockSyntax)(source, expectedOperationTree, expectedDiagnostics)
@@ -251,8 +251,8 @@ End Class]]>.Value
 
             Dim expectedOperationTree = <![CDATA[
 ILockStatement (OperationKind.LockStatement) (Syntax: 'SyncLock M2 ... nd SyncLock')
-  Expression: IInvocationExpression ( Function ConsoleApp2.C1.M2() As System.Object) (OperationKind.InvocationExpression, Type: System.Object) (Syntax: 'M2()')
-      Instance Receiver: IInstanceReferenceExpression (InstanceReferenceKind.Implicit) (OperationKind.InstanceReferenceExpression, Type: ConsoleApp2.C1) (Syntax: 'M2')
+  Expression: IInvocationExpression ( Function C1.M2() As System.Object) (OperationKind.InvocationExpression, Type: System.Object) (Syntax: 'M2()')
+      Instance Receiver: IInstanceReferenceExpression (InstanceReferenceKind.Implicit) (OperationKind.InstanceReferenceExpression, Type: C1) (Syntax: 'M2')
       Arguments(0)
   Body: IBlockStatement (0 statements) (OperationKind.BlockStatement) (Syntax: 'SyncLock M2 ... nd SyncLock')
 ]]>.Value
@@ -282,8 +282,8 @@ End Class]]>.Value
 ILockStatement (OperationKind.LockStatement, IsInvalid) (Syntax: 'SyncLock M2 ... nd SyncLock')
   Expression: IInvalidExpression (OperationKind.InvalidExpression, Type: ?, IsInvalid) (Syntax: 'M2()')
       Children(1):
-          IInvocationExpression ( Sub ConsoleApp2.C1.M2()) (OperationKind.InvocationExpression, Type: System.Void, IsInvalid) (Syntax: 'M2()')
-            Instance Receiver: IInstanceReferenceExpression (InstanceReferenceKind.Implicit) (OperationKind.InstanceReferenceExpression, Type: ConsoleApp2.C1, IsInvalid) (Syntax: 'M2')
+          IInvocationExpression ( Sub C1.M2()) (OperationKind.InvocationExpression, Type: System.Void, IsInvalid) (Syntax: 'M2()')
+            Instance Receiver: IInstanceReferenceExpression (InstanceReferenceKind.Implicit) (OperationKind.InstanceReferenceExpression, Type: C1, IsInvalid) (Syntax: 'M2')
             Arguments(0)
   Body: IBlockStatement (0 statements) (OperationKind.BlockStatement, IsInvalid) (Syntax: 'SyncLock M2 ... nd SyncLock')
 ]]>.Value
@@ -291,7 +291,7 @@ ILockStatement (OperationKind.LockStatement, IsInvalid) (Syntax: 'SyncLock M2 ..
             Dim expectedDiagnostics = <![CDATA[
 BC30491: Expression does not produce a value.
         SyncLock M2()'BIND:"SyncLock M2()"
-                                                            ~
+                 ~~~~
 ]]>.Value
 
             VerifyOperationTreeAndDiagnosticsForTest(Of SyncLockBlockSyntax)(source, expectedOperationTree, expectedDiagnostics)

From 358dbb65cf0e7b8932674a3434cf7488ae070240 Mon Sep 17 00:00:00 2001
From: Fredric Silberberg <frsilb@microsoft.com>
Date: Tue, 15 Aug 2017 10:32:50 -0700
Subject: [PATCH 60/77] More test fixes.

---
 .../Semantic/IOperation/IOperationTests_ILockStatement.vb     | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_ILockStatement.vb b/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_ILockStatement.vb
index 41bb967e51dbc..cede38039493e 100644
--- a/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_ILockStatement.vb
+++ b/src/Compilers/VisualBasic/Test/Semantic/IOperation/IOperationTests_ILockStatement.vb
@@ -178,7 +178,7 @@ BC30451: 'InvalidReference' is not declared. It may be inaccessible due to its p
 
         <CompilerTrait(CompilerFeature.IOperation)>
         <Fact()>
-        Public Sub ILockExpression_MissingEndLock()
+        Public Sub ILockStatement_MissingEndLock()
             Dim source = <![CDATA[
 Option Strict On
 
@@ -199,7 +199,7 @@ ILockStatement (OperationKind.LockStatement, IsInvalid) (Syntax: 'SyncLock o' ..
             Dim expectedDiagnostics = <![CDATA[
 BC30675: 'SyncLock' statement must end with a matching 'End SyncLock'.
         SyncLock o'BIND:"SyncLock o"
-                                                                                         ~
+        ~~~~~~~~~~
 ]]>.Value
 
             VerifyOperationTreeAndDiagnosticsForTest(Of SyncLockBlockSyntax)(source, expectedOperationTree, expectedDiagnostics)

From 1bb513eb9d7280778fd876ba39925a98bb3ebdd9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tom=C3=A1=C5=A1=20Matou=C5=A1ek?=
 <tmat@users.noreply.github.com>
Date: Tue, 15 Aug 2017 10:50:40 -0700
Subject: [PATCH 61/77] OSS sign debugger binaries. (#21468)

---
 src/Tools/GenerateSdkPackages/make-all.ps1 | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/src/Tools/GenerateSdkPackages/make-all.ps1 b/src/Tools/GenerateSdkPackages/make-all.ps1
index ac1b8966dd826..17b576fc0d863 100644
--- a/src/Tools/GenerateSdkPackages/make-all.ps1
+++ b/src/Tools/GenerateSdkPackages/make-all.ps1
@@ -28,14 +28,17 @@ function Package-Normal() {
 # The debugger DLLs have a more complex structure and it's easier to special case
 # copying them over.
 function Copy-Debugger() { 
-    $debuggerRefDir = Join-Path $dllPath "debugger\ref"
-    $debuggerImplDir = Join-Path $dllPath "debugger\lib\net45"
+    $debuggerDir = Join-Path $dllPath "debugger"
+    $debuggerRefDir = Join-Path $debuggerDir "ref"
+    $debuggerImplDir = Join-Path $debuggerDir "lib\net45"
     Create-Directory $debuggerRefDir
     Create-Directory $debuggerImplDir
     
     Copy-Item -re -fo (Join-Path $dropPath "..\..\Debugger\ReferenceDLL\*") $debuggerRefDir
     Copy-Item -re -fo (Join-Path $dropPath "..\..\Debugger\IDE\Microsoft.VisualStudio.Debugger.Engine.dll") $debuggerImplDir
     Copy-Item -re -fo (Join-Path $dropPath "Microsoft.VisualStudio.Debugger.Metadata.dll") $debuggerImplDir
+    
+    Get-ChildItem $debuggerDir -Recurse -File | ForEach-Object { & $fakeSign -f $_.FullName }
 }
 
 # Used to package debugger nugets

From fc856a087161fb1e2fab35107de09cb03ef61c1f Mon Sep 17 00:00:00 2001
From: Ravi Chande <rchande@microsoft.com>
Date: Tue, 15 Aug 2017 10:55:47 -0700
Subject: [PATCH 62/77] fix merge issues

---
 build/Targets/Packages.props                  |  1 +
 .../NavigableSymbolService.NavigableSymbol.cs | 61 ---------------
 ...ableSymbolService.NavigableSymbolSource.cs | 76 -------------------
 .../Core/NavigableSymbolService.cs            | 39 ----------
 .../Test2/NavigableSymbolsTest.vb             | 73 ------------------
 .../Utilities/GoToHelpers/GoToTestHelpers.vb  |  3 +-
 6 files changed, 2 insertions(+), 251 deletions(-)
 delete mode 100644 src/EditorFeatures/Core/NavigableSymbolService.NavigableSymbol.cs
 delete mode 100644 src/EditorFeatures/Core/NavigableSymbolService.NavigableSymbolSource.cs
 delete mode 100644 src/EditorFeatures/Core/NavigableSymbolService.cs
 delete mode 100644 src/EditorFeatures/Test2/NavigableSymbolsTest.vb

diff --git a/build/Targets/Packages.props b/build/Targets/Packages.props
index 9a3b18b9ff8f4..0a52400e4c8d8 100644
--- a/build/Targets/Packages.props
+++ b/build/Targets/Packages.props
@@ -106,6 +106,7 @@
     <MicrosoftVisualStudioShellInterop121DesignTimeVersion>12.1.30328</MicrosoftVisualStudioShellInterop121DesignTimeVersion>
     <MicrosoftVisualStudioShellInterop140DesignTimeVersion>14.3.25407</MicrosoftVisualStudioShellInterop140DesignTimeVersion>
     <MicrosoftVisualStudioShellInterop150DesignTimeVersion>15.0.26606-alpha</MicrosoftVisualStudioShellInterop150DesignTimeVersion>
+	<MicrosoftVisualStudioShellInterop153DesignTimeVersion>15.0.26606</MicrosoftVisualStudioShellInterop153DesignTimeVersion>
     <MicrosoftVisualStudioShellInterop80Version>8.0.50727</MicrosoftVisualStudioShellInterop80Version>
     <MicrosoftVisualStudioShellInterop90Version>9.0.30729</MicrosoftVisualStudioShellInterop90Version>
     <MicrosoftVisualStudioTelemetryVersion>15.0.26606-alpha</MicrosoftVisualStudioTelemetryVersion>
diff --git a/src/EditorFeatures/Core/NavigableSymbolService.NavigableSymbol.cs b/src/EditorFeatures/Core/NavigableSymbolService.NavigableSymbol.cs
deleted file mode 100644
index 94921c91aca09..0000000000000
--- a/src/EditorFeatures/Core/NavigableSymbolService.NavigableSymbol.cs
+++ /dev/null
@@ -1,61 +0,0 @@
-// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
-
-using System;
-using System.Collections.Generic;
-using System.Collections.Immutable;
-using Microsoft.CodeAnalysis.Editor.GoToDefinition;
-using Microsoft.CodeAnalysis.Editor.Host;
-using Microsoft.CodeAnalysis.FindUsages;
-using Microsoft.VisualStudio.Language.Intellisense;
-using Microsoft.VisualStudio.Text;
-using Roslyn.Utilities;
-
-namespace Microsoft.CodeAnalysis.Editor.NavigableSymbols
-{
-    internal partial class NavigableSymbolService
-    {
-        private class NavigableSymbol : INavigableSymbol
-        {
-            private readonly ImmutableArray<DefinitionItem> _definitions;
-            private readonly SnapshotSpan _span;
-            private readonly Document _document;
-            private readonly IEnumerable<Lazy<IStreamingFindUsagesPresenter>> _presenters;
-            private readonly IWaitIndicator _waitIndicator;
-
-            public NavigableSymbol(
-                ImmutableArray<DefinitionItem> definitions,
-                SnapshotSpan span,
-                Document document,
-                IEnumerable<Lazy<IStreamingFindUsagesPresenter>> streamingPresenters,
-                IWaitIndicator waitIndicator)
-            {
-                Contract.ThrowIfFalse(definitions.Length > 0);
-
-                _definitions = definitions;
-                _span = span;
-                _document = document;
-                _presenters = streamingPresenters;
-                _waitIndicator = waitIndicator;
-            }
-
-            public SnapshotSpan SymbolSpan => _span;
-
-            public IEnumerable<INavigableRelationship> Relationships =>
-                SpecializedCollections.SingletonEnumerable(PredefinedNavigableRelationships.Definition);
-
-            public void Navigate(INavigableRelationship relationship) =>
-                _waitIndicator.Wait(
-                    title: EditorFeaturesResources.Go_to_Definition,
-                    message: EditorFeaturesResources.Navigating_to_definition,
-                    allowCancel: true,
-                    showProgress: false,
-                    action: context => GoToDefinitionHelpers.TryGoToDefinition(
-                        _definitions,
-                        _document.Project,
-                        _definitions[0].NameDisplayParts.GetFullText(),
-                        _presenters,
-                        context.CancellationToken)
-                    );
-        }
-    }
-}
diff --git a/src/EditorFeatures/Core/NavigableSymbolService.NavigableSymbolSource.cs b/src/EditorFeatures/Core/NavigableSymbolService.NavigableSymbolSource.cs
deleted file mode 100644
index 418279a87be0a..0000000000000
--- a/src/EditorFeatures/Core/NavigableSymbolService.NavigableSymbolSource.cs
+++ /dev/null
@@ -1,76 +0,0 @@
-// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
-
-using System;
-using System.Collections.Generic;
-using System.Collections.Immutable;
-using System.Linq;
-using System.Threading;
-using System.Threading.Tasks;
-using Microsoft.CodeAnalysis.Editor.GoToDefinition;
-using Microsoft.CodeAnalysis.Editor.Host;
-using Microsoft.CodeAnalysis.Shared.Extensions;
-using Microsoft.CodeAnalysis.Text;
-using Microsoft.VisualStudio.Language.Intellisense;
-using Microsoft.VisualStudio.Text;
-using Microsoft.VisualStudio.Text.Editor;
-
-namespace Microsoft.CodeAnalysis.Editor.NavigableSymbols
-{
-    internal partial class NavigableSymbolService
-    {
-        private partial class NavigableSymbolSource : INavigableSymbolSource
-        {
-            private readonly IEnumerable<Lazy<IStreamingFindUsagesPresenter>> _presenters;
-            private readonly IWaitIndicator _waitIndicator;
-
-            private bool _disposed;
-
-            public NavigableSymbolSource(
-                IEnumerable<Lazy<IStreamingFindUsagesPresenter>> streamingPresenters,
-                IWaitIndicator waitIndicator)
-            {
-                _presenters = streamingPresenters;
-                _waitIndicator = waitIndicator;
-            }
-
-            public void Dispose()
-            {
-                _disposed = true;
-            }
-
-            public async Task<INavigableSymbol> GetNavigableSymbolAsync(SnapshotSpan triggerSpan, CancellationToken cancellationToken)
-            {
-                if (_disposed)
-                {
-                    return null;
-                }
-
-                var snapshot = triggerSpan.Snapshot;
-                var position = triggerSpan.Start;
-                var document = snapshot.GetOpenDocumentInCurrentContextWithChanges();
-                if (document == null)
-                {
-                    return null;
-                }
-
-                var service = document.GetLanguageService<IGoToSymbolService>();
-
-                var context = new GoToDefinitionContext(
-                    document, 
-                    position, 
-                    cancellationToken: cancellationToken);
-
-                await service.GetDefinitionsAsync(context).ConfigureAwait(false);
-
-                if (!context.Items.TryGetValue(WellKnownDefinitionTypes.Definition, out var definitions))
-                {
-                    return null;
-                }
-
-                var span = context.Span;
-                var snapshotSpan = new SnapshotSpan(snapshot, span.Start, span.Length);
-                return new NavigableSymbol(definitions.ToImmutableArray(), snapshotSpan, document, _presenters, _waitIndicator);
-            }
-        }
-    }
-}
diff --git a/src/EditorFeatures/Core/NavigableSymbolService.cs b/src/EditorFeatures/Core/NavigableSymbolService.cs
deleted file mode 100644
index c1b6c945ea297..0000000000000
--- a/src/EditorFeatures/Core/NavigableSymbolService.cs
+++ /dev/null
@@ -1,39 +0,0 @@
-// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
-
-using System;
-using System.Collections.Generic;
-using System.ComponentModel.Composition;
-using Microsoft.CodeAnalysis.Editor.Host;
-using Microsoft.CodeAnalysis.Editor.Shared.Extensions;
-using Microsoft.VisualStudio.Language.Intellisense;
-using Microsoft.VisualStudio.Text;
-using Microsoft.VisualStudio.Text.Editor;
-using Microsoft.VisualStudio.Utilities;
-
-namespace Microsoft.CodeAnalysis.Editor.NavigableSymbols
-{
-    [Export(typeof(INavigableSymbolSourceProvider))]
-    [Name(nameof(NavigableSymbolService))]
-    [ContentType(ContentTypeNames.RoslynContentType)]
-    internal partial class NavigableSymbolService : INavigableSymbolSourceProvider
-    {
-        private static readonly object s_key = new object();
-        private readonly IEnumerable<Lazy<IStreamingFindUsagesPresenter>> _streamingPresenters;
-        private readonly IWaitIndicator _waitIndicator;
-
-        [ImportingConstructor]
-        public NavigableSymbolService(
-            IWaitIndicator waitIndicator,
-            [ImportMany] IEnumerable<Lazy<IStreamingFindUsagesPresenter>> streamingPresenters)
-        {
-            _waitIndicator = waitIndicator;
-            _streamingPresenters = streamingPresenters;
-        }
-
-        public INavigableSymbolSource TryCreateNavigableSymbolSource(ITextView textView, ITextBuffer buffer)
-        {
-            return textView.GetOrCreatePerSubjectBufferProperty(buffer, s_key,
-                (v, b) => new NavigableSymbolSource(_streamingPresenters, _waitIndicator));
-        }
-    }
-}
diff --git a/src/EditorFeatures/Test2/NavigableSymbolsTest.vb b/src/EditorFeatures/Test2/NavigableSymbolsTest.vb
deleted file mode 100644
index 5c3d2ecaee323..0000000000000
--- a/src/EditorFeatures/Test2/NavigableSymbolsTest.vb
+++ /dev/null
@@ -1,73 +0,0 @@
-' Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
-
-Imports System
-Imports System.Linq
-Imports System.Threading
-Imports System.Threading.Tasks
-Imports Microsoft.CodeAnalysis.Editor.Host
-Imports Microsoft.CodeAnalysis.Editor.NavigableSymbols
-Imports Microsoft.CodeAnalysis.Editor.UnitTests.BraceMatching
-Imports Microsoft.CodeAnalysis.Editor.UnitTests.Utilities
-Imports Microsoft.CodeAnalysis.Editor.UnitTests.Utilities.GoToHelpers
-Imports Microsoft.CodeAnalysis.Editor.UnitTests.Workspaces
-Imports Microsoft.CodeAnalysis.Navigation
-Imports Microsoft.VisualStudio.Composition
-Imports Microsoft.VisualStudio.Text
-Imports Roslyn.Test.Utilities
-Imports Xunit
-
-Namespace Microsoft.CodeAnalysis.Editor.UnitTests.NavigableSymbols
-
-    Public Class NavigableSymbolsTest
-
-        Private Shared ReadOnly s_exportProvider As ExportProvider = MinimalTestExportProvider.CreateExportProvider(
-            TestExportProvider.EntireAssemblyCatalogWithCSharpAndVisualBasic.WithParts(
-                GetType(MockDocumentNavigationServiceProvider),
-                GetType(MockSymbolNavigationServiceProvider)))
-
-        <WpfFact>
-        Public Async Function TestCharp() As Task
-            Using workspace = TestWorkspace.CreateCSharp("
-class C
-{
-    C$$ c
-}", exportProvider:=s_exportProvider)
-
-
-                Await TestNavigated(workspace)
-            End Using
-        End Function
-
-        <WpfFact>
-        Public Async Function TestVB() As Task
-            Using workspace = TestWorkspace.CreateVisualBasic("
-Class C
-    Dim c as C$$
-End Class", exportProvider:=s_exportProvider)
-
-
-                Await TestNavigated(workspace)
-            End Using
-        End Function
-
-        Private Async Function TestNavigated(workspace As TestWorkspace) As Task
-
-            Dim presenter = {New Lazy(Of IStreamingFindUsagesPresenter)(Function() New MockStreamingFindUsagesPresenter(Sub() Return))}
-            Dim service = New NavigableSymbolService(TestWaitIndicator.Default, presenter)
-            Dim view = workspace.Documents.First().GetTextView()
-            Dim Buffer = workspace.Documents.First().GetTextBuffer()
-            Dim caretPosition = view.Caret.Position.BufferPosition.Position
-            Dim Span = New SnapshotSpan(Buffer.CurrentSnapshot, New Span(caretPosition, 0))
-            Dim source = service.TryCreateNavigableSymbolSource(view, Buffer)
-            Dim symbol = Await source.GetNavigableSymbolAsync(Span, CancellationToken.None)
-
-            Assert.NotNull(symbol)
-            symbol.Navigate(symbol.Relationships.First())
-
-            Dim navigationService = DirectCast(workspace.Services.GetService(Of IDocumentNavigationService)(), MockDocumentNavigationServiceProvider.MockDocumentNavigationService)
-            Assert.Equal(True, navigationService.TryNavigateToLineAndOffsetReturnValue)
-            Assert.Equal(True, navigationService.TryNavigateToPositionReturnValue)
-            Assert.Equal(True, navigationService.TryNavigateToSpanReturnValue)
-        End Function
-    End Class
-End Namespace
diff --git a/src/EditorFeatures/TestUtilities2/Utilities/GoToHelpers/GoToTestHelpers.vb b/src/EditorFeatures/TestUtilities2/Utilities/GoToHelpers/GoToTestHelpers.vb
index a6013afac9595..7aa821193daa1 100644
--- a/src/EditorFeatures/TestUtilities2/Utilities/GoToHelpers/GoToTestHelpers.vb
+++ b/src/EditorFeatures/TestUtilities2/Utilities/GoToHelpers/GoToTestHelpers.vb
@@ -17,9 +17,8 @@ Namespace Microsoft.CodeAnalysis.Editor.UnitTests.Utilities.GoToHelpers
         Public ReadOnly Catalog As ComposableCatalog = TestExportProvider.MinimumCatalogWithCSharpAndVisualBasic.WithParts(
                         GetType(MockDocumentNavigationServiceFactory),
                         GetType(DefaultSymbolNavigationServiceFactory),
-                        GetType(GeneratedCodeRecognitionService),
                         GetType(CSharpGoToDefinitionSymbolService),
-                        GetType(VisualBasicGoToDefinitionSymbolService))
+                        GetType(VisualBasicGoToDefinitionSymbolService),
                         GetType(CSharpGeneratedCodeRecognitionService),
                         GetType(VisualBasicGeneratedCodeRecognitionService))
 

From ad58d125e2b579f8789305b0259b992a8af24bcd Mon Sep 17 00:00:00 2001
From: Fredric Silberberg <frsilb@microsoft.com>
Date: Tue, 15 Aug 2017 11:16:46 -0700
Subject: [PATCH 63/77] Fixed unintentional capitalization change.

---
 .../Operations/VisualBasicOperationFactory.vb      | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb b/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
index bdbc96ea52edf..64f079c606814 100644
--- a/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
+++ b/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
@@ -286,7 +286,7 @@ Namespace Microsoft.CodeAnalysis.Semantics
         End Function
 
         Private Function CreateBoundMeReferenceOperation(boundMeReference As BoundMeReference) As IInstanceReferenceExpression
-            Dim instanceReferenceKind As InstanceReferenceKind = If(boundMeReference.WasCompilerGenerated, instanceReferenceKind.Implicit, instanceReferenceKind.Explicit)
+            Dim instanceReferenceKind As InstanceReferenceKind = If(boundMeReference.WasCompilerGenerated, InstanceReferenceKind.Implicit, InstanceReferenceKind.Explicit)
             Dim syntax As SyntaxNode = boundMeReference.Syntax
             Dim type As ITypeSymbol = boundMeReference.Type
             Dim constantValue As [Optional](Of Object) = ConvertToOptional(boundMeReference.ConstantValueOpt)
@@ -295,7 +295,7 @@ Namespace Microsoft.CodeAnalysis.Semantics
         End Function
 
         Private Function CreateBoundMyBaseReferenceOperation(boundMyBaseReference As BoundMyBaseReference) As IInstanceReferenceExpression
-            Dim instanceReferenceKind As InstanceReferenceKind = instanceReferenceKind.BaseClass
+            Dim instanceReferenceKind As InstanceReferenceKind = InstanceReferenceKind.BaseClass
             Dim syntax As SyntaxNode = boundMyBaseReference.Syntax
             Dim type As ITypeSymbol = boundMyBaseReference.Type
             Dim constantValue As [Optional](Of Object) = ConvertToOptional(boundMyBaseReference.ConstantValueOpt)
@@ -304,7 +304,7 @@ Namespace Microsoft.CodeAnalysis.Semantics
         End Function
 
         Private Function CreateBoundMyClassReferenceOperation(boundMyClassReference As BoundMyClassReference) As IInstanceReferenceExpression
-            Dim instanceReferenceKind As InstanceReferenceKind = instanceReferenceKind.ThisClass
+            Dim instanceReferenceKind As InstanceReferenceKind = InstanceReferenceKind.ThisClass
             Dim syntax As SyntaxNode = boundMyClassReference.Syntax
             Dim type As ITypeSymbol = boundMyClassReference.Type
             Dim constantValue As [Optional](Of Object) = ConvertToOptional(boundMyClassReference.ConstantValueOpt)
@@ -471,7 +471,7 @@ Namespace Microsoft.CodeAnalysis.Semantics
         End Function
 
         Private Function CreateBoundUserDefinedShortCircuitingOperatorOperation(boundUserDefinedShortCircuitingOperator As BoundUserDefinedShortCircuitingOperator) As IBinaryOperatorExpression
-            Dim binaryOperationKind As BinaryOperationKind = If((boundUserDefinedShortCircuitingOperator.BitwiseOperator.OperatorKind And BinaryOperatorKind.And) <> 0, binaryOperationKind.OperatorMethodConditionalAnd, binaryOperationKind.OperatorMethodConditionalOr)
+            Dim binaryOperationKind As BinaryOperationKind = If((boundUserDefinedShortCircuitingOperator.BitwiseOperator.OperatorKind And BinaryOperatorKind.And) <> 0, BinaryOperationKind.OperatorMethodConditionalAnd, BinaryOperationKind.OperatorMethodConditionalOr)
             Dim leftOperand As Lazy(Of IOperation) = New Lazy(Of IOperation)(Function() Create(boundUserDefinedShortCircuitingOperator.LeftOperand))
             Dim rightOperand As Lazy(Of IOperation) = New Lazy(Of IOperation)(Function() Create(boundUserDefinedShortCircuitingOperator.BitwiseOperator.Right))
             Dim usesOperatorMethod As Boolean = True
@@ -1073,7 +1073,7 @@ Namespace Microsoft.CodeAnalysis.Semantics
 
         Private Function CreateBoundGotoStatementOperation(boundGotoStatement As BoundGotoStatement) As IBranchStatement
             Dim target As ILabelSymbol = boundGotoStatement.Label
-            Dim branchKind As BranchKind = branchKind.GoTo
+            Dim branchKind As BranchKind = BranchKind.GoTo
             Dim syntax As SyntaxNode = boundGotoStatement.Syntax
             Dim type As ITypeSymbol = Nothing
             Dim constantValue As [Optional](Of Object) = New [Optional](Of Object)()
@@ -1083,7 +1083,7 @@ Namespace Microsoft.CodeAnalysis.Semantics
 
         Private Function CreateBoundContinueStatementOperation(boundContinueStatement As BoundContinueStatement) As IBranchStatement
             Dim target As ILabelSymbol = boundContinueStatement.Label
-            Dim branchKind As BranchKind = branchKind.Continue
+            Dim branchKind As BranchKind = BranchKind.Continue
             Dim syntax As SyntaxNode = boundContinueStatement.Syntax
             Dim type As ITypeSymbol = Nothing
             Dim constantValue As [Optional](Of Object) = New [Optional](Of Object)()
@@ -1093,7 +1093,7 @@ Namespace Microsoft.CodeAnalysis.Semantics
 
         Private Function CreateBoundExitStatementOperation(boundExitStatement As BoundExitStatement) As IBranchStatement
             Dim target As ILabelSymbol = boundExitStatement.Label
-            Dim branchKind As BranchKind = branchKind.Break
+            Dim branchKind As BranchKind = BranchKind.Break
             Dim syntax As SyntaxNode = boundExitStatement.Syntax
             Dim type As ITypeSymbol = Nothing
             Dim constantValue As [Optional](Of Object) = New [Optional](Of Object)()

From 8a80db80b1a7814ca6d10cce2081d6140085a623 Mon Sep 17 00:00:00 2001
From: CyrusNajmabadi <cyrusn@microsoft.com>
Date: Tue, 15 Aug 2017 12:16:46 -0700
Subject: [PATCH 64/77] Fix regression in VB attribute classification.

---
 .../Classification/SemanticClassifierTests.vb | 11 +++++++
 .../NameSyntaxClassifier.cs                   | 31 +++++++------------
 .../NameSyntaxClassifier.vb                   |  6 ++++
 3 files changed, 28 insertions(+), 20 deletions(-)

diff --git a/src/EditorFeatures/VisualBasicTest/Classification/SemanticClassifierTests.vb b/src/EditorFeatures/VisualBasicTest/Classification/SemanticClassifierTests.vb
index 9cecc4b998c31..aeddc8d9debdc 100644
--- a/src/EditorFeatures/VisualBasicTest/Classification/SemanticClassifierTests.vb
+++ b/src/EditorFeatures/VisualBasicTest/Classification/SemanticClassifierTests.vb
@@ -545,5 +545,16 @@ end sub
 
             Await TestInClassAsync(text)
         End Function
+
+        <WorkItem(21524, "https://github.com/dotnet/roslyn/issues/21524")>
+        <Fact, Trait(Traits.Feature, Traits.Features.Classification)>
+        Public Async Function TestAttribute() As Task
+            Await TestAsync("Imports System
+
+<AttributeUsage()>
+Class Program
+End Class",
+                [Class]("AttributeUsage"))
+        End Function
     End Class
 End Namespace
diff --git a/src/Workspaces/CSharp/Portable/Classification/SyntaxClassification/NameSyntaxClassifier.cs b/src/Workspaces/CSharp/Portable/Classification/SyntaxClassification/NameSyntaxClassifier.cs
index c56c793ddbf32..05e5d2b8431d8 100644
--- a/src/Workspaces/CSharp/Portable/Classification/SyntaxClassification/NameSyntaxClassifier.cs
+++ b/src/Workspaces/CSharp/Portable/Classification/SyntaxClassification/NameSyntaxClassifier.cs
@@ -123,17 +123,11 @@ private static bool IsNamespaceName(NameSyntax name)
             CancellationToken cancellationToken,
             out ClassifiedSpan classifiedSpan)
         {
-            if (symbol != null)
+            // Classify a reference to an attribute constructor in an attribute location
+            // as if we were classifying the attribute type itself.
+            if (symbol.IsConstructor() && name.IsParentKind(SyntaxKind.Attribute))
             {
-                // see through using aliases
-                if (symbol.Kind == SymbolKind.Alias)
-                {
-                    symbol = (symbol as IAliasSymbol).Target;
-                }
-                else if (symbol.IsConstructor() && name.IsParentKind(SyntaxKind.Attribute))
-                {
-                    symbol = symbol.ContainingType;
-                }
+                symbol = symbol.ContainingType;
             }
 
             if (name.IsVar &&
@@ -153,18 +147,15 @@ private static bool IsNamespaceName(NameSyntax name)
                 }
             }
 
-            if (symbol != null)
+            // Use .Equals since we can't rely on object identity for constructed types.
+            if (symbol is ITypeSymbol typeSymbol)
             {
-                // Use .Equals since we can't rely on object identity for constructed types.
-                if (symbol is ITypeSymbol typeSymbol)
+                var classification = GetClassificationForType(typeSymbol);
+                if (classification != null)
                 {
-                    var classification = GetClassificationForType(typeSymbol);
-                    if (classification != null)
-                    {
-                        var token = name.GetNameToken();
-                        classifiedSpan = new ClassifiedSpan(token.Span, classification);
-                        return true;
-                    }
+                    var token = name.GetNameToken();
+                    classifiedSpan = new ClassifiedSpan(token.Span, classification);
+                    return true;
                 }
             }
 
diff --git a/src/Workspaces/VisualBasic/Portable/Classification/SyntaxClassification/NameSyntaxClassifier.vb b/src/Workspaces/VisualBasic/Portable/Classification/SyntaxClassification/NameSyntaxClassifier.vb
index c2a9b6a29dbc0..1102cfb65b96e 100644
--- a/src/Workspaces/VisualBasic/Portable/Classification/SyntaxClassification/NameSyntaxClassifier.vb
+++ b/src/Workspaces/VisualBasic/Portable/Classification/SyntaxClassification/NameSyntaxClassifier.vb
@@ -64,6 +64,12 @@ Namespace Microsoft.CodeAnalysis.VisualBasic.Classification.Classifiers
                 End Select
             End If
 
+            ' Classify a reference to an attribute constructor in an attribute location
+            ' as if we were classifying the attribute type itself.
+            If symbol.IsConstructor() AndAlso node.IsParentKind(SyntaxKind.Attribute) Then
+                symbol = symbol.ContainingType
+            End If
+
             If symbol IsNot Nothing Then
                 If symbol.Kind = SymbolKind.Method Then
                     Dim method = DirectCast(symbol, IMethodSymbol)

From 995f32ad7964b22f22bca7bc8b5ebea2ce9631a1 Mon Sep 17 00:00:00 2001
From: CyrusNajmabadi <cyrusn@microsoft.com>
Date: Tue, 15 Aug 2017 12:37:40 -0700
Subject: [PATCH 65/77] Improve find-refs behavior when the user invokes it
 with a symbol selected.

---
 .../FindReferencesCommandHandler.cs              | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/EditorFeatures/Core/FindReferences/FindReferencesCommandHandler.cs b/src/EditorFeatures/Core/FindReferences/FindReferencesCommandHandler.cs
index 3617e587702d8..b67b909c603e9 100644
--- a/src/EditorFeatures/Core/FindReferences/FindReferencesCommandHandler.cs
+++ b/src/EditorFeatures/Core/FindReferences/FindReferencesCommandHandler.cs
@@ -53,15 +53,23 @@ public CommandState GetCommandState(FindReferencesCommandArgs args, Func<Command
 
         public void ExecuteCommand(FindReferencesCommandArgs args, Action nextHandler)
         {
-            var caretPosition = args.TextView.GetCaretPoint(args.SubjectBuffer) ?? -1;
-
-            if (caretPosition >= 0)
+            // Get the selection that user has in our buffer (this also works if there
+            // is no selection and the caret is just at a single position).  If we 
+            // can't get the selection, or there are multiple spans for it (i.e. a 
+            // box selection), then don't do anything.
+            var snapshotSpans = args.TextView.Selection.GetSnapshotSpansOnBuffer(args.SubjectBuffer);
+            if (snapshotSpans.Count == 1)
             {
+                var selectedSpan = snapshotSpans[0];
                 var snapshot = args.SubjectBuffer.CurrentSnapshot;
                 var document = snapshot.GetOpenDocumentInCurrentContextWithChanges();
                 if (document != null)
                 {
-                    if (TryExecuteCommand(caretPosition, document))
+                    // Do a find-refs at the *start* of the selection.  That way if the
+                    // user has selected a symbol that has another symbol touching it
+                    // on the right (i.e.  Goo++  ), then we'll do the find-refs on the
+                    // symbol selected, not the symbol following.
+                    if (TryExecuteCommand(selectedSpan.Start, document))
                     {
                         return;
                     }

From d48f4ccf462f4a9ae26085542b59b8dba8dacfbe Mon Sep 17 00:00:00 2001
From: CyrusNajmabadi <cyrusn@microsoft.com>
Date: Tue, 15 Aug 2017 13:10:32 -0700
Subject: [PATCH 66/77] Add test.

---
 .../FindReferencesCommandHandlerTests.vb      | 86 +++++++++++++++++++
 .../FindReferences/FindReferencesTests.vb     |  2 +-
 .../Shared/TestHooks/FeatureMetadata.cs       |  5 +-
 3 files changed, 91 insertions(+), 2 deletions(-)
 create mode 100644 src/EditorFeatures/Test2/FindReferences/FindReferencesCommandHandlerTests.vb

diff --git a/src/EditorFeatures/Test2/FindReferences/FindReferencesCommandHandlerTests.vb b/src/EditorFeatures/Test2/FindReferences/FindReferencesCommandHandlerTests.vb
new file mode 100644
index 0000000000000..9f0b987d6781d
--- /dev/null
+++ b/src/EditorFeatures/Test2/FindReferences/FindReferencesCommandHandlerTests.vb
@@ -0,0 +1,86 @@
+' Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.
+
+Imports System.Threading.Tasks
+Imports Microsoft.CodeAnalysis.Editor.Commands
+Imports Microsoft.CodeAnalysis.Editor.FindReferences
+Imports Microsoft.CodeAnalysis.Editor.Host
+Imports Microsoft.CodeAnalysis.Editor.UnitTests.Workspaces
+Imports Microsoft.CodeAnalysis.FindUsages
+Imports Microsoft.CodeAnalysis.Shared.TestHooks
+Imports Microsoft.CodeAnalysis.Text.Shared.Extensions
+
+Namespace Microsoft.CodeAnalysis.Editor.UnitTests.FindReferences
+    Public Class FindReferencesCommandHandlerTests
+        <WorkItem(47594, "https://developercommunity.visualstudio.com/content/problem/47594/c-postfix-operators-inhibit-find-all-references-sh.html")>
+        <WpfFact, Trait(Traits.Feature, Traits.Features.Completion)>
+        Public Async Function TestSelection() As Task
+            Dim source = "
+class C
+{
+    void M()
+    {
+        int {|Definition:yyy|} = 0;
+        {|Reference:{|Selection:yyy|}|}++;
+        {|Reference:yyy|}++;
+    }
+}"
+            Using workspace = TestWorkspace.CreateCSharp(source)
+                Dim testDocument = workspace.Documents.Single()
+
+                Dim view = testDocument.GetTextView()
+                Dim textBuffer = view.TextBuffer
+                Dim snapshot = textBuffer.CurrentSnapshot
+
+                view.Selection.Select(
+                    testDocument.AnnotatedSpans("Selection").Single().ToSnapshotSpan(snapshot), isReversed:=False)
+
+                Dim waiter = New Waiter()
+
+                Dim context = New FindReferencesTests.TestContext()
+                Dim commandHandler = New FindReferencesCommandHandler(
+                    workspace.GetService(Of IWaitIndicator),
+                    {}, {New Lazy(Of IStreamingFindUsagesPresenter)(Function() New MockStreamingFindReferencesPresenter(context))},
+                    {New Lazy(Of IAsynchronousOperationListener, FeatureMetadata)(Function() waiter, New FeatureMetadata(FeatureAttribute.FindReferences))})
+
+                Dim document = workspace.CurrentSolution.GetDocument(testDocument.Id)
+                commandHandler.ExecuteCommand(
+                    New FindReferencesCommandArgs(view, textBuffer), Sub()
+                                                                     End Sub)
+
+                ' Wait for the find refs to be done.
+                Await waiter.CreateWaitTask()
+
+                Assert.Equal(1, context.Definitions.Count)
+                Assert.Equal(testDocument.AnnotatedSpans("Definition").Single(),
+                             context.Definitions(0).SourceSpans.Single().SourceSpan)
+                Assert.Equal(testDocument.AnnotatedSpans("Reference").Count,
+                             context.References.Count)
+
+                AssertEx.SetEqual(testDocument.AnnotatedSpans("Reference"),
+                                  context.References.Select(Function(r) r.SourceSpan.SourceSpan))
+            End Using
+        End Function
+
+        Private Class MockStreamingFindReferencesPresenter
+            Implements IStreamingFindUsagesPresenter
+
+            Private ReadOnly _context As FindReferencesTests.TestContext
+
+            Public Sub New(context As FindReferencesTests.TestContext)
+                _context = context
+            End Sub
+
+            Public Sub ClearAll() Implements IStreamingFindUsagesPresenter.ClearAll
+            End Sub
+
+            Public Function StartSearch(title As String, supportsReferences As Boolean) As FindUsagesContext Implements IStreamingFindUsagesPresenter.StartSearch
+                Return _context
+            End Function
+        End Class
+
+        Private Class Waiter
+            Inherits AsynchronousOperationListener
+
+        End Class
+    End Class
+End Namespace
diff --git a/src/EditorFeatures/Test2/FindReferences/FindReferencesTests.vb b/src/EditorFeatures/Test2/FindReferences/FindReferencesTests.vb
index dd69fcc741852..878737e6dea7b 100644
--- a/src/EditorFeatures/Test2/FindReferences/FindReferencesTests.vb
+++ b/src/EditorFeatures/Test2/FindReferences/FindReferencesTests.vb
@@ -125,7 +125,7 @@ Namespace Microsoft.CodeAnalysis.Editor.UnitTests.FindReferences
 
         End Structure
 
-        Private Class TestContext
+        Friend Class TestContext
             Inherits FindUsagesContext
 
             Private ReadOnly gate As Object = New Object()
diff --git a/src/Features/Core/Portable/Shared/TestHooks/FeatureMetadata.cs b/src/Features/Core/Portable/Shared/TestHooks/FeatureMetadata.cs
index 618ceab3af11b..59b7c17ccefdf 100644
--- a/src/Features/Core/Portable/Shared/TestHooks/FeatureMetadata.cs
+++ b/src/Features/Core/Portable/Shared/TestHooks/FeatureMetadata.cs
@@ -19,8 +19,11 @@ internal class FeatureMetadata
         public string FeatureName { get; }
 
         public FeatureMetadata(IDictionary<string, object> data)
+            : this((string)data.GetValueOrDefault("FeatureName"))
         {
-            this.FeatureName = (string)data.GetValueOrDefault("FeatureName");
         }
+
+        public FeatureMetadata(string featureName)
+            => FeatureName = featureName;
     }
 }

From 5d6f76f2885115d852c3b1ddec81c03647c0dabc Mon Sep 17 00:00:00 2001
From: Andy Gocke <angocke@microsoft.com>
Date: Tue, 15 Aug 2017 13:11:06 -0700
Subject: [PATCH 67/77] Fix bug in 'this' optimization for classes (#21510)

In the introduction of the new 'this' optimization routine,
one of the things which was changed was to treat 'this' more
like a formal parameter of the method, as opposed to a variable
living in an implicit, higher scope. This has some advantages
in simplicity for analysis, but created a problem when it came
to proxies. The current analysis builds the proxy list by walking
the tree and finding all captured variables and adding them
to the proxy dictionary keyed by the original variable symbol.
For instance, if a local variable is captured to a field, during
rewriting it will be added to the proxy list as (original symbol,
hoisted field). Since most symbols are only ever captured to a
single replacement field, this usually works fine -- all proxies
can exist side-by-side in the proxy list since there is no intersection.

However, this is not true for captured environment pointers. When
a new environment is introduced, a local will be created to point
to that environment. That local may itself be captured by nested
variables, creating a linked list from nested scopes to parent scope.
Most notably, *multiple* nested environments may capture the *same*
environment pointer in *different* hoisted fields. This means that
the proxies dictionary cannot hold all mappings at once, since the
mapping for a given captured environment pointer will depend on the
current scope.

The current code actually accounts for this already by adding a
captured environment pointer to the proxy list on a nested scope's
introduction, and removing it upon leaving that scope.

By changing 'this' to be treated like a formal parameter, I
circumvented this logic, introducing a bug. When two scopes tried
to capture the 'this' pointer, the compiler crashed due to trying
to add two mappings to the same key.

This change fixes this problem by treating the 'this' parameter
like an environment pointer for the purposes of capturing and
hoisting. It's possible that we want to treat it like a formal
parameter, but if so it's probably better to treat all captured
environment pointers the same way and introduce a scope-aware
notion of proxies, rather than having a global dictionary.

Fixes #21506
---
 .../LambdaRewriter/LambdaRewriter.Analysis.cs | 39 ++---------
 .../Lowering/LambdaRewriter/LambdaRewriter.cs |  3 +-
 .../Emit/CodeGen/CodeGenLocalFunctionTests.cs | 66 +++++++++++++++++++
 3 files changed, 74 insertions(+), 34 deletions(-)

diff --git a/src/Compilers/CSharp/Portable/Lowering/LambdaRewriter/LambdaRewriter.Analysis.cs b/src/Compilers/CSharp/Portable/Lowering/LambdaRewriter/LambdaRewriter.Analysis.cs
index 98a3179932f70..216cca9ee6d9e 100644
--- a/src/Compilers/CSharp/Portable/Lowering/LambdaRewriter/LambdaRewriter.Analysis.cs
+++ b/src/Compilers/CSharp/Portable/Lowering/LambdaRewriter/LambdaRewriter.Analysis.cs
@@ -246,9 +246,13 @@ private void InlineThisOnlyEnvironments()
                 }
                 else
                 {
-                    // Class-based 'this' closures can move member functions
-                    // to the top-level type and environments which capture
-                    // the 'this' environment can capture 'this' directly
+                    // Class-based 'this' closures can move member functions to
+                    // the top-level type and environments which capture the 'this'
+                    // environment can capture 'this' directly.
+                    // Note: the top-level type is treated as the initial containing
+                    // environment, so by removing the 'this' environment, all
+                    // nested environments which captured a pointer to the 'this'
+                    // environment will now capture 'this'
                     RemoveEnv();
                     VisitClosures(ScopeTree, (scope, closure) =>
                     {
@@ -257,35 +261,6 @@ private void InlineThisOnlyEnvironments()
                             closure.ContainingEnvironmentOpt = null;
                         }
                     });
-
-                    // Find all environments in the scope below that could
-                    // capture the parent. If there are any, add 'this' to
-                    // the list of captured variables and remove the parent
-                    // link
-                    VisitFirstLevelScopes(ScopeTree);
-                    void VisitFirstLevelScopes(Scope scope)
-                    {
-                        var classEnvs = scope.DeclaredEnvironments.Where(e => !e.IsStruct);
-                        if (classEnvs.IsEmpty())
-                        {
-                            // Keep looking for nested environments
-                            foreach (var nested in scope.NestedScopes)
-                            {
-                                VisitFirstLevelScopes(nested);
-                            }
-                        }
-                        else
-                        {
-                            foreach (var declEnv in classEnvs)
-                            {
-                                if (declEnv.CapturesParent)
-                                {
-                                    declEnv.CapturedVariables.Insert(0, thisParam);
-                                    declEnv.CapturesParent = false;
-                                }
-                            }
-                        }
-                    }
                 }
 
                 void RemoveEnv()
diff --git a/src/Compilers/CSharp/Portable/Lowering/LambdaRewriter/LambdaRewriter.cs b/src/Compilers/CSharp/Portable/Lowering/LambdaRewriter/LambdaRewriter.cs
index 1e4c9b4c98d11..9a8c3dc5de783 100644
--- a/src/Compilers/CSharp/Portable/Lowering/LambdaRewriter/LambdaRewriter.cs
+++ b/src/Compilers/CSharp/Portable/Lowering/LambdaRewriter/LambdaRewriter.cs
@@ -187,8 +187,7 @@ public MappedLocalFunction(SynthesizedLambdaMethod symbol, ClosureKind closureKi
             _assignLocals = assignLocals;
             _currentTypeParameters = method.TypeParameters;
             _currentLambdaBodyTypeMap = TypeMap.Empty;
-            _innermostFramePointer = null;
-            _currentFrameThis = thisParameterOpt;
+            _innermostFramePointer = _currentFrameThis = thisParameterOpt;
             _framePointers[thisType] = thisParameterOpt;
             _seenBaseCall = method.MethodKind != MethodKind.Constructor; // only used for ctors
             _synthesizedFieldNameIdDispenser = 1;
diff --git a/src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenLocalFunctionTests.cs b/src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenLocalFunctionTests.cs
index 653af28ed10ed..efc27dfc74c8f 100644
--- a/src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenLocalFunctionTests.cs
+++ b/src/Compilers/CSharp/Test/Emit/CodeGen/CodeGenLocalFunctionTests.cs
@@ -30,6 +30,72 @@ public static IMethodSymbol FindLocalFunction(this CompilationVerifier verifier,
     [CompilerTrait(CompilerFeature.LocalFunctions)]
     public class CodeGenLocalFunctionTests : CSharpTestBase
     {
+        [Fact]
+        public void CaptureThisInDifferentScopes()
+        {
+            CompileAndVerify(@"
+using System;
+class C
+{
+    int _x;
+    void M()
+    {
+        {
+            int y = 0;
+            Func<int> f1 = () => _x + y;
+        }
+        {
+            int y = 0;
+            Func<int> f2 = () => _x + y;
+        }
+    }
+}");
+        }
+
+        [Fact]
+        public void CaptureThisInDifferentScopes2()
+        {
+            CompileAndVerify(@"
+using System;
+class C
+{
+    int _x;
+    void M()
+    {
+        {
+            int y = 0;
+            int L1() => _x + y;
+        }
+        {
+            int y = 0;
+            int L2() => _x + y;
+        }
+    }
+}");
+        }
+
+        [Fact]
+        public void CaptureFramePointerInDifferentScopes()
+        {
+            CompileAndVerify(@"
+using System;
+class C
+{
+    void M(int x)
+    {
+        Func<int> f1 = () => x;
+        {
+            int z = 0;
+            Func<int> f2 = () => x + z;
+        }
+        {
+            int z = 0;
+            Func<int> f3 = () => x + z;
+        }
+    }
+}");
+        }
+
         [Fact]
         public void EnvironmentChainContainsStructEnvironment()
         {

From dd1ccca0f3fddd72ebbb7f954c772b531e215a10 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tom=C3=A1=C5=A1=20Matou=C5=A1ek?=
 <tmat@users.noreply.github.com>
Date: Tue, 15 Aug 2017 13:12:04 -0700
Subject: [PATCH 68/77] Remove Release subdir from template output path
 (#21482)

---
 build/config/SignToolData.json       | 2 +-
 src/Setup/Templates/Templates.csproj | 4 +---
 2 files changed, 2 insertions(+), 4 deletions(-)

diff --git a/build/config/SignToolData.json b/build/config/SignToolData.json
index 1d6bfc3ed7269..a79c0812b76a5 100644
--- a/build/config/SignToolData.json
+++ b/build/config/SignToolData.json
@@ -102,7 +102,7 @@
         "Vsix\\VisualStudioSetup.Next\\Roslyn.VisualStudio.Setup.Next.vsix",
         "Vsix\\VisualStudioSetup\\Roslyn.VisualStudio.Setup.vsix",
         "Vsix\\Roslyn\\RoslynDeployment.vsix",
-        "Vsix\\Templates\\Roslyn Templates\\Release\\Roslyn SDK.vsix"
+        "Vsix\\Templates\\Roslyn SDK.vsix"
       ]
     }
   ],
diff --git a/src/Setup/Templates/Templates.csproj b/src/Setup/Templates/Templates.csproj
index f88a473213435..2f992acc4e33b 100644
--- a/src/Setup/Templates/Templates.csproj
+++ b/src/Setup/Templates/Templates.csproj
@@ -17,9 +17,7 @@
     <IncludeDebugSymbolsInLocalVSIXDeployment>false</IncludeDebugSymbolsInLocalVSIXDeployment>
     <DeployVSTemplates>false</DeployVSTemplates>
     <CopyZipOutputToOutputDirectory>false</CopyZipOutputToOutputDirectory>
-    <BaseIntermediateOutputPath>$(BaseIntermediateOutputPath)\$(VersionType)\</BaseIntermediateOutputPath>
-    <VsixOutDirSuffix>Roslyn Templates\$(VersionType)</VsixOutDirSuffix>
-    <TargetVsixContainerName>$(VsixOutDirSuffix)\Roslyn SDK.vsix</TargetVsixContainerName>
+    <TargetVsixContainerName>Roslyn SDK.vsix</TargetVsixContainerName>
     <ImportVSSDKTargets>true</ImportVSSDKTargets>
     <MinimumVisualStudioVersion>$(VisualStudioVersion)</MinimumVisualStudioVersion>
     <TargetFrameworkVersion>v4.6</TargetFrameworkVersion>

From a23840ef687719d594e7d00a69ae504de95316e1 Mon Sep 17 00:00:00 2001
From: Fredric Silberberg <frsilb@microsoft.com>
Date: Tue, 15 Aug 2017 14:39:47 -0700
Subject: [PATCH 69/77] Fixed unintentional capitalization change.

---
 .../Operations/VisualBasicOperationFactory.vb      | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb b/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
index 9156af43fe01f..4ed3d157992bf 100644
--- a/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
+++ b/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
@@ -286,7 +286,7 @@ Namespace Microsoft.CodeAnalysis.Semantics
         End Function
 
         Private Function CreateBoundMeReferenceOperation(boundMeReference As BoundMeReference) As IInstanceReferenceExpression
-            Dim instanceReferenceKind As InstanceReferenceKind = If(boundMeReference.WasCompilerGenerated, instanceReferenceKind.Implicit, instanceReferenceKind.Explicit)
+            Dim instanceReferenceKind As InstanceReferenceKind = If(boundMeReference.WasCompilerGenerated, InstanceReferenceKind.Implicit, InstanceReferenceKind.Explicit)
             Dim syntax As SyntaxNode = boundMeReference.Syntax
             Dim type As ITypeSymbol = boundMeReference.Type
             Dim constantValue As [Optional](Of Object) = ConvertToOptional(boundMeReference.ConstantValueOpt)
@@ -295,7 +295,7 @@ Namespace Microsoft.CodeAnalysis.Semantics
         End Function
 
         Private Function CreateBoundMyBaseReferenceOperation(boundMyBaseReference As BoundMyBaseReference) As IInstanceReferenceExpression
-            Dim instanceReferenceKind As InstanceReferenceKind = instanceReferenceKind.BaseClass
+            Dim instanceReferenceKind As InstanceReferenceKind = InstanceReferenceKind.BaseClass
             Dim syntax As SyntaxNode = boundMyBaseReference.Syntax
             Dim type As ITypeSymbol = boundMyBaseReference.Type
             Dim constantValue As [Optional](Of Object) = ConvertToOptional(boundMyBaseReference.ConstantValueOpt)
@@ -304,7 +304,7 @@ Namespace Microsoft.CodeAnalysis.Semantics
         End Function
 
         Private Function CreateBoundMyClassReferenceOperation(boundMyClassReference As BoundMyClassReference) As IInstanceReferenceExpression
-            Dim instanceReferenceKind As InstanceReferenceKind = instanceReferenceKind.ThisClass
+            Dim instanceReferenceKind As InstanceReferenceKind = InstanceReferenceKind.ThisClass
             Dim syntax As SyntaxNode = boundMyClassReference.Syntax
             Dim type As ITypeSymbol = boundMyClassReference.Type
             Dim constantValue As [Optional](Of Object) = ConvertToOptional(boundMyClassReference.ConstantValueOpt)
@@ -471,7 +471,7 @@ Namespace Microsoft.CodeAnalysis.Semantics
         End Function
 
         Private Function CreateBoundUserDefinedShortCircuitingOperatorOperation(boundUserDefinedShortCircuitingOperator As BoundUserDefinedShortCircuitingOperator) As IBinaryOperatorExpression
-            Dim binaryOperationKind As BinaryOperationKind = If((boundUserDefinedShortCircuitingOperator.BitwiseOperator.OperatorKind And BinaryOperatorKind.And) <> 0, binaryOperationKind.OperatorMethodConditionalAnd, binaryOperationKind.OperatorMethodConditionalOr)
+            Dim binaryOperationKind As BinaryOperationKind = If((boundUserDefinedShortCircuitingOperator.BitwiseOperator.OperatorKind And BinaryOperatorKind.And) <> 0, BinaryOperationKind.OperatorMethodConditionalAnd, BinaryOperationKind.OperatorMethodConditionalOr)
             Dim leftOperand As Lazy(Of IOperation) = New Lazy(Of IOperation)(Function() Create(boundUserDefinedShortCircuitingOperator.LeftOperand))
             Dim rightOperand As Lazy(Of IOperation) = New Lazy(Of IOperation)(Function() Create(boundUserDefinedShortCircuitingOperator.BitwiseOperator.Right))
             Dim usesOperatorMethod As Boolean = True
@@ -1075,7 +1075,7 @@ Namespace Microsoft.CodeAnalysis.Semantics
 
         Private Function CreateBoundGotoStatementOperation(boundGotoStatement As BoundGotoStatement) As IBranchStatement
             Dim target As ILabelSymbol = boundGotoStatement.Label
-            Dim branchKind As BranchKind = branchKind.GoTo
+            Dim branchKind As BranchKind = BranchKind.GoTo
             Dim syntax As SyntaxNode = boundGotoStatement.Syntax
             Dim type As ITypeSymbol = Nothing
             Dim constantValue As [Optional](Of Object) = New [Optional](Of Object)()
@@ -1085,7 +1085,7 @@ Namespace Microsoft.CodeAnalysis.Semantics
 
         Private Function CreateBoundContinueStatementOperation(boundContinueStatement As BoundContinueStatement) As IBranchStatement
             Dim target As ILabelSymbol = boundContinueStatement.Label
-            Dim branchKind As BranchKind = branchKind.Continue
+            Dim branchKind As BranchKind = BranchKind.Continue
             Dim syntax As SyntaxNode = boundContinueStatement.Syntax
             Dim type As ITypeSymbol = Nothing
             Dim constantValue As [Optional](Of Object) = New [Optional](Of Object)()
@@ -1095,7 +1095,7 @@ Namespace Microsoft.CodeAnalysis.Semantics
 
         Private Function CreateBoundExitStatementOperation(boundExitStatement As BoundExitStatement) As IBranchStatement
             Dim target As ILabelSymbol = boundExitStatement.Label
-            Dim branchKind As BranchKind = branchKind.Break
+            Dim branchKind As BranchKind = BranchKind.Break
             Dim syntax As SyntaxNode = boundExitStatement.Syntax
             Dim type As ITypeSymbol = Nothing
             Dim constantValue As [Optional](Of Object) = New [Optional](Of Object)()

From fb111160f6fed3168c17af48ceb9c1b35a613668 Mon Sep 17 00:00:00 2001
From: CyrusNajmabadi <cyrusn@microsoft.com>
Date: Tue, 15 Aug 2017 15:01:14 -0700
Subject: [PATCH 70/77] Do a better job with leading trivia on types when
 moving types to a new file.

---
 .../MoveType/MoveTypeTests.MoveToNewFile.cs   | 111 +++++++++++++++++-
 .../MoveType/MoveTypeTests.MoveToNewFile.vb   |  96 ++++++++++++++-
 .../AbstractMoveTypeService.MoveTypeEditor.cs |  21 ++--
 .../CSharpSyntaxFactsService.cs               |   3 +
 .../SyntaxFactsService/ISyntaxFactsService.cs |   1 +
 .../VisualBasicSyntaxFactsService.vb          |   6 +
 6 files changed, 221 insertions(+), 17 deletions(-)

diff --git a/src/EditorFeatures/CSharpTest/CodeActions/MoveType/MoveTypeTests.MoveToNewFile.cs b/src/EditorFeatures/CSharpTest/CodeActions/MoveType/MoveTypeTests.MoveToNewFile.cs
index 16c9b9b7722fe..292557f34f343 100644
--- a/src/EditorFeatures/CSharpTest/CodeActions/MoveType/MoveTypeTests.MoveToNewFile.cs
+++ b/src/EditorFeatures/CSharpTest/CodeActions/MoveType/MoveTypeTests.MoveToNewFile.cs
@@ -179,6 +179,7 @@ class Class2 { }";
             var destinationDocumentText =
 @"// Banner Text
 using System;
+
 class Class1 
 { 
     void Print(int x)
@@ -230,6 +231,7 @@ void Print(int x)
             var destinationDocumentText =
 @"// Banner Text
 using System;
+
 class Class1 
 { 
     void Print(int x)
@@ -998,7 +1000,8 @@ static void Main()
 
             var expectedDocumentName = "Inner.cs";
             var destinationDocumentText =
-@"#if true
+@"
+#if true
 public class Inner
 {
 
@@ -1066,5 +1069,111 @@ public class Inner
             await TestMoveTypeToNewFileAsync(
                 code, codeAfterMove, expectedDocumentName, destinationDocumentText, ignoreTrivia: false);
         }
+
+        [WorkItem(21456, "https://github.com/dotnet/roslyn/issues/21456")]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        public async Task TestLeadingBlankLines1()
+        {
+            var code =
+@"// Banner Text
+using System;
+
+[||]class Class1
+{
+    void Foo()
+    {
+        Console.WriteLine();
+    }
+}
+
+class Class2
+{
+    void Foo()
+    {
+        Console.WriteLine();
+    }
+}
+";
+            var codeAfterMove = @"// Banner Text
+using System;
+
+class Class2
+{
+    void Foo()
+    {
+        Console.WriteLine();
+    }
+}
+";
+
+            var expectedDocumentName = "Class1.cs";
+            var destinationDocumentText = @"// Banner Text
+using System;
+
+class Class1
+{
+    void Foo()
+    {
+        Console.WriteLine();
+    }
+}
+";
+
+            await TestMoveTypeToNewFileAsync(
+                code, codeAfterMove, expectedDocumentName, destinationDocumentText);
+        }
+
+        [WorkItem(21456, "https://github.com/dotnet/roslyn/issues/21456")]
+        [WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)]
+        public async Task TestLeadingBlankLines2()
+        {
+            var code =
+@"// Banner Text
+using System;
+
+class Class1
+{
+    void Foo()
+    {
+        Console.WriteLine();
+    }
+}
+
+[||]class Class2
+{
+    void Foo()
+    {
+        Console.WriteLine();
+    }
+}
+";
+            var codeAfterMove = @"// Banner Text
+using System;
+
+class Class1
+{
+    void Foo()
+    {
+        Console.WriteLine();
+    }
+}
+";
+
+            var expectedDocumentName = "Class2.cs";
+            var destinationDocumentText = @"// Banner Text
+using System;
+
+class Class2
+{
+    void Foo()
+    {
+        Console.WriteLine();
+    }
+}
+";
+
+            await TestMoveTypeToNewFileAsync(
+                code, codeAfterMove, expectedDocumentName, destinationDocumentText);
+        }
     }
 }
diff --git a/src/EditorFeatures/VisualBasicTest/CodeActions/MoveType/MoveTypeTests.MoveToNewFile.vb b/src/EditorFeatures/VisualBasicTest/CodeActions/MoveType/MoveTypeTests.MoveToNewFile.vb
index 4475eb204bb8d..2089fa5071c80 100644
--- a/src/EditorFeatures/VisualBasicTest/CodeActions/MoveType/MoveTypeTests.MoveToNewFile.vb
+++ b/src/EditorFeatures/VisualBasicTest/CodeActions/MoveType/MoveTypeTests.MoveToNewFile.vb
@@ -26,11 +26,11 @@ End Class
 "
 
             Await TestMissingInRegularAndScriptAsync(code)
-    End Function
+        End Function
 
-    <WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)>
-    Public Async Function MultipleTypesInFileWithNoContainerNamespace() As Task
-        Dim code =
+        <WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)>
+        Public Async Function MultipleTypesInFileWithNoContainerNamespace() As Task
+            Dim code =
 "
 [||]Class Class1
 End Class
@@ -224,5 +224,93 @@ End Class
 "
             Await TestMoveTypeToNewFileAsync(code, codeAfterMove, expectedDocumentName, destinationDocumentText)
         End Function
+
+        <WorkItem(21456, "https://github.com/dotnet/roslyn/issues/21456")>
+        <WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)>
+        Public Async Function TestLeadingBlankLines1() As Task
+            Dim code =
+"' Banner Text
+imports System
+
+[||]class Class1
+    sub Foo()
+        Console.WriteLine()
+    end sub
+end class
+
+class Class2
+    sub Foo()
+        Console.WriteLine()
+    end sub
+end class
+"
+            Dim codeAfterMove = "' Banner Text
+imports System
+
+class Class2
+    sub Foo()
+        Console.WriteLine()
+    end sub
+end class
+"
+
+            Dim expectedDocumentName = "Class1.vb"
+            Dim destinationDocumentText = "' Banner Text
+imports System
+
+class Class1
+    sub Foo()
+        Console.WriteLine()
+    end sub
+end class
+"
+
+            Await TestMoveTypeToNewFileAsync(
+                code, codeAfterMove, expectedDocumentName, destinationDocumentText)
+        End Function
+
+        <WorkItem(21456, "https://github.com/dotnet/roslyn/issues/21456")>
+        <WpfFact, Trait(Traits.Feature, Traits.Features.CodeActionsMoveType)>
+        Public Async Function TestLeadingBlankLines2() As Task
+            Dim code =
+"' Banner Text
+imports System
+
+class Class1
+    sub Foo()
+        Console.WriteLine()
+    end sub
+end class
+
+[||]class Class2
+    sub Foo()
+        Console.WriteLine()
+    end sub
+end class
+"
+            Dim codeAfterMove = "' Banner Text
+imports System
+
+class Class1
+    sub Foo()
+        Console.WriteLine()
+    end sub
+end class
+"
+
+            Dim expectedDocumentName = "Class2.vb"
+            Dim destinationDocumentText = "' Banner Text
+imports System
+
+class Class2
+    sub Foo()
+        Console.WriteLine()
+    end sub
+end class
+"
+
+            Await TestMoveTypeToNewFileAsync(
+                code, codeAfterMove, expectedDocumentName, destinationDocumentText)
+        End Function
     End Class
 End Namespace
diff --git a/src/Features/Core/Portable/CodeRefactorings/MoveType/AbstractMoveTypeService.MoveTypeEditor.cs b/src/Features/Core/Portable/CodeRefactorings/MoveType/AbstractMoveTypeService.MoveTypeEditor.cs
index f19e2f513252b..e79fc52e01e57 100644
--- a/src/Features/Core/Portable/CodeRefactorings/MoveType/AbstractMoveTypeService.MoveTypeEditor.cs
+++ b/src/Features/Core/Portable/CodeRefactorings/MoveType/AbstractMoveTypeService.MoveTypeEditor.cs
@@ -271,24 +271,21 @@ private static bool FilterToTopLevelMembers(SyntaxNode node, SyntaxNode typeNode
                     {
                         var currentTypeNode = (TTypeDeclarationSyntax)currentNode;
 
-                        // Trim leading whitespace from the type so we don't have excessive
-                        // leading blank lines.
-                        return RemoveLeadingWhitespace(currentTypeNode);
+                        // Trim leading blank lines from the type so we don't have an 
+                        // excessive number of them.
+                        return RemoveLeadingBlankLines(currentTypeNode);
                     });
             }
 
-            private TTypeDeclarationSyntax RemoveLeadingWhitespace(
+            private TTypeDeclarationSyntax RemoveLeadingBlankLines(
                 TTypeDeclarationSyntax currentTypeNode)
             {
                 var syntaxFacts = State.SemanticDocument.Document.GetLanguageService<ISyntaxFactsService>();
-                var leadingTrivia = currentTypeNode.GetLeadingTrivia();
-                var afterWhitespace = leadingTrivia.SkipWhile(
-                    t => syntaxFacts.IsWhitespaceTrivia(t) || syntaxFacts.IsEndOfLineTrivia(t));
-
-                var withoutLeadingWhitespace = currentTypeNode.WithLeadingTrivia(afterWhitespace);
-                return withoutLeadingWhitespace.ReplaceToken(
-                    withoutLeadingWhitespace.GetFirstToken(),
-                    withoutLeadingWhitespace.GetFirstToken().WithAdditionalAnnotations(Formatter.Annotation));
+                var withoutBlankLines = syntaxFacts.GetNodeWithoutLeadingBlankLines(currentTypeNode);
+
+                // Add an elastic marker so the formatter can add any blank lines it thinks are
+                // important to have (i.e. after a block of usings/imports).
+                return withoutBlankLines.WithPrependedLeadingTrivia(syntaxFacts.ElasticMarker);
             }
         }
     }
diff --git a/src/Workspaces/CSharp/Portable/LanguageServices/CSharpSyntaxFactsService.cs b/src/Workspaces/CSharp/Portable/LanguageServices/CSharpSyntaxFactsService.cs
index f04663fd044a1..ca4153cff96e6 100644
--- a/src/Workspaces/CSharp/Portable/LanguageServices/CSharpSyntaxFactsService.cs
+++ b/src/Workspaces/CSharp/Portable/LanguageServices/CSharpSyntaxFactsService.cs
@@ -33,6 +33,9 @@ private CSharpSyntaxFactsService()
 
         public StringComparer StringComparer { get; } = StringComparer.Ordinal;
 
+        public SyntaxTrivia ElasticMarker
+            => SyntaxFactory.ElasticMarker;
+
         public SyntaxTrivia ElasticCarriageReturnLineFeed
             => SyntaxFactory.ElasticCarriageReturnLineFeed;
 
diff --git a/src/Workspaces/Core/Portable/LanguageServices/SyntaxFactsService/ISyntaxFactsService.cs b/src/Workspaces/Core/Portable/LanguageServices/SyntaxFactsService/ISyntaxFactsService.cs
index 9732f4d8b0b12..310c6c1307a34 100644
--- a/src/Workspaces/Core/Portable/LanguageServices/SyntaxFactsService/ISyntaxFactsService.cs
+++ b/src/Workspaces/Core/Portable/LanguageServices/SyntaxFactsService/ISyntaxFactsService.cs
@@ -14,6 +14,7 @@ internal interface ISyntaxFactsService : ILanguageService
         bool IsCaseSensitive { get; }
         StringComparer StringComparer { get; }
 
+        SyntaxTrivia ElasticMarker { get; }
         SyntaxTrivia ElasticCarriageReturnLineFeed { get; }
 
         bool SupportsIndexingInitializer(ParseOptions options);
diff --git a/src/Workspaces/VisualBasic/Portable/LanguageServices/VisualBasicSyntaxFactsService.vb b/src/Workspaces/VisualBasic/Portable/LanguageServices/VisualBasicSyntaxFactsService.vb
index 33e2eb31ab0a0..0b9fe01a99455 100644
--- a/src/Workspaces/VisualBasic/Portable/LanguageServices/VisualBasicSyntaxFactsService.vb
+++ b/src/Workspaces/VisualBasic/Portable/LanguageServices/VisualBasicSyntaxFactsService.vb
@@ -46,6 +46,12 @@ Namespace Microsoft.CodeAnalysis.VisualBasic
             End Get
         End Property
 
+        Public ReadOnly Property ElasticMarker As SyntaxTrivia Implements ISyntaxFactsService.ElasticMarker
+            Get
+                Return SyntaxFactory.ElasticMarker
+            End Get
+        End Property
+
         Public ReadOnly Property ElasticCarriageReturnLineFeed As SyntaxTrivia Implements ISyntaxFactsService.ElasticCarriageReturnLineFeed
             Get
                 Return SyntaxFactory.ElasticCarriageReturnLineFeed

From ee5ba5e54dc815e95082372c0f029d5fe0f21fdc Mon Sep 17 00:00:00 2001
From: Fredric Silberberg <frsilb@microsoft.com>
Date: Tue, 15 Aug 2017 15:26:32 -0700
Subject: [PATCH 71/77] Fixed unintentional capitalization change, corrected
 grammar.

---
 .../Portable/Operations/IAnonymousFunctionExpression.cs   | 2 +-
 .../Portable/Operations/VisualBasicOperationFactory.vb    | 8 ++++----
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/src/Compilers/Core/Portable/Operations/IAnonymousFunctionExpression.cs b/src/Compilers/Core/Portable/Operations/IAnonymousFunctionExpression.cs
index 4eb29d38732e4..580502bc74737 100644
--- a/src/Compilers/Core/Portable/Operations/IAnonymousFunctionExpression.cs
+++ b/src/Compilers/Core/Portable/Operations/IAnonymousFunctionExpression.cs
@@ -5,7 +5,7 @@
 namespace Microsoft.CodeAnalysis.Semantics
 {
     /// <summary>
-    /// Represents a anonymous function expression, such as a lambda or anonymous delegate.
+    /// Represents an anonymous function expression, such as a lambda or anonymous delegate.
     /// </summary>
     /// <remarks>
     /// This interface is reserved for implementation by its associated APIs. We reserve the right to
diff --git a/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb b/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
index 64bf1f5d4251f..cb61a26e1d535 100644
--- a/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
+++ b/src/Compilers/VisualBasic/Portable/Operations/VisualBasicOperationFactory.vb
@@ -286,7 +286,7 @@ Namespace Microsoft.CodeAnalysis.Semantics
         End Function
 
         Private Function CreateBoundMeReferenceOperation(boundMeReference As BoundMeReference) As IInstanceReferenceExpression
-            Dim instanceReferenceKind As InstanceReferenceKind = If(boundMeReference.WasCompilerGenerated, instanceReferenceKind.Implicit, instanceReferenceKind.Explicit)
+            Dim instanceReferenceKind As InstanceReferenceKind = If(boundMeReference.WasCompilerGenerated, InstanceReferenceKind.Implicit, InstanceReferenceKind.Explicit)
             Dim syntax As SyntaxNode = boundMeReference.Syntax
             Dim type As ITypeSymbol = boundMeReference.Type
             Dim constantValue As [Optional](Of Object) = ConvertToOptional(boundMeReference.ConstantValueOpt)
@@ -1073,7 +1073,7 @@ Namespace Microsoft.CodeAnalysis.Semantics
 
         Private Function CreateBoundGotoStatementOperation(boundGotoStatement As BoundGotoStatement) As IBranchStatement
             Dim target As ILabelSymbol = boundGotoStatement.Label
-            Dim branchKind As BranchKind = branchKind.GoTo
+            Dim branchKind As BranchKind = BranchKind.GoTo
             Dim syntax As SyntaxNode = boundGotoStatement.Syntax
             Dim type As ITypeSymbol = Nothing
             Dim constantValue As [Optional](Of Object) = New [Optional](Of Object)()
@@ -1083,7 +1083,7 @@ Namespace Microsoft.CodeAnalysis.Semantics
 
         Private Function CreateBoundContinueStatementOperation(boundContinueStatement As BoundContinueStatement) As IBranchStatement
             Dim target As ILabelSymbol = boundContinueStatement.Label
-            Dim branchKind As BranchKind = branchKind.Continue
+            Dim branchKind As BranchKind = BranchKind.Continue
             Dim syntax As SyntaxNode = boundContinueStatement.Syntax
             Dim type As ITypeSymbol = Nothing
             Dim constantValue As [Optional](Of Object) = New [Optional](Of Object)()
@@ -1093,7 +1093,7 @@ Namespace Microsoft.CodeAnalysis.Semantics
 
         Private Function CreateBoundExitStatementOperation(boundExitStatement As BoundExitStatement) As IBranchStatement
             Dim target As ILabelSymbol = boundExitStatement.Label
-            Dim branchKind As BranchKind = branchKind.Break
+            Dim branchKind As BranchKind = BranchKind.Break
             Dim syntax As SyntaxNode = boundExitStatement.Syntax
             Dim type As ITypeSymbol = Nothing
             Dim constantValue As [Optional](Of Object) = New [Optional](Of Object)()

From 2f61dcf484b80cb74b91d198eab4a1fa20d741ed Mon Sep 17 00:00:00 2001
From: CyrusNajmabadi <cyrusn@microsoft.com>
Date: Tue, 15 Aug 2017 16:39:09 -0700
Subject: [PATCH 72/77] Update comment

---
 ...tractReplaceDocCommentTextWithTagCodeRefactoringProvider.cs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/Features/Core/Portable/ReplaceDocCommentTextWithTag/AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider.cs b/src/Features/Core/Portable/ReplaceDocCommentTextWithTag/AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
index 970efc775c619..1b1eb576b8505 100644
--- a/src/Features/Core/Portable/ReplaceDocCommentTextWithTag/AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
+++ b/src/Features/Core/Portable/ReplaceDocCommentTextWithTag/AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
@@ -93,7 +93,8 @@ public override async Task ComputeRefactoringsAsync(CodeRefactoringContext conte
                 return;
             }
 
-            // Look up the term inside the named type if we're inside of one.
+            // Doc comments on a named type can see the members inside of it.  So check
+            // inside the named type for a member that matches.
             if (symbol is INamedTypeSymbol namedType)
             {
                 var childMember = namedType.GetMembers().FirstOrDefault(m => syntaxFacts.StringComparer.Equals(m.Name, singleWordText));

From b698cbb3354b4f67351b6761c2a9870392bfca38 Mon Sep 17 00:00:00 2001
From: Andy Gocke <angocke@microsoft.com>
Date: Tue, 15 Aug 2017 16:42:09 -0700
Subject: [PATCH 73/77] Move integration test machines to 15.3 RTM (#21535)

---
 netci.groovy | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/netci.groovy b/netci.groovy
index 46ac6eb09bcde..e69bbaf1373dc 100644
--- a/netci.groovy
+++ b/netci.groovy
@@ -226,7 +226,7 @@ commitPullList.each { isPr ->
 
       def triggerPhraseOnly = false
       def triggerPhraseExtra = ""
-      Utilities.setMachineAffinity(myJob, 'Windows_NT', 'latest-dev15-3-preview7')
+      Utilities.setMachineAffinity(myJob, 'Windows_NT', 'latest-dev15-3')
       Utilities.addXUnitDotNETResults(myJob, '**/xUnitResults/*.xml')
       addRoslynJob(myJob, jobName, branchName, isPr, triggerPhraseExtra, triggerPhraseOnly)
     }

From d6436768b9c9409c1b06acbc1c2d1196b60c2a97 Mon Sep 17 00:00:00 2001
From: CyrusNajmabadi <cyrusn@microsoft.com>
Date: Tue, 15 Aug 2017 16:42:43 -0700
Subject: [PATCH 74/77] Rename method.

---
 ...eDocCommentTextWithTagCodeRefactoringProvider.cs | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/src/Features/Core/Portable/ReplaceDocCommentTextWithTag/AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider.cs b/src/Features/Core/Portable/ReplaceDocCommentTextWithTag/AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
index 1b1eb576b8505..0a309b778a2fc 100644
--- a/src/Features/Core/Portable/ReplaceDocCommentTextWithTag/AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
+++ b/src/Features/Core/Portable/ReplaceDocCommentTextWithTag/AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
@@ -70,7 +70,8 @@ public override async Task ComputeRefactoringsAsync(CodeRefactoringContext conte
             if (fullyQualifiedSpan != singleWordSpan)
             {
                 var fullyQualifiedText = sourceText.ToString(fullyQualifiedSpan);
-                if (TryParseAndBindText(context, semanticModel, token, fullyQualifiedSpan, fullyQualifiedText))
+                if (TryRegisterSeeCrefTagIfSymbol(
+                        context, semanticModel, token, fullyQualifiedSpan, cancellationToken))
                 {
                     return;
                 }
@@ -107,12 +108,16 @@ public override async Task ComputeRefactoringsAsync(CodeRefactoringContext conte
 
             // Finally, try to speculatively bind the name and see if it binds to anything
             // in the surrounding context.
-            TryParseAndBindText(context, semanticModel, token, singleWordSpan, singleWordText);
+            TryRegisterSeeCrefTagIfSymbol(
+                context, semanticModel, token, singleWordSpan, cancellationToken);
         }
 
-        private bool TryParseAndBindText(
-            CodeRefactoringContext context, SemanticModel semanticModel, SyntaxToken token, TextSpan replacementSpan, string text)
+        private bool TryRegisterSeeCrefTagIfSymbol(
+            CodeRefactoringContext context, SemanticModel semanticModel, SyntaxToken token, TextSpan replacementSpan, CancellationToken cancellationToken)
         {
+            var sourceText = semanticModel.SyntaxTree.GetText(cancellationToken);
+            var text = sourceText.ToString(replacementSpan);
+
             var parsed = ParseExpression(text);
             var foundSymbol = semanticModel.GetSpeculativeSymbolInfo(token.SpanStart, parsed, SpeculativeBindingOption.BindAsExpression).GetAnySymbol();
             if (foundSymbol == null)

From 254a63118a8b8bb13acd4f64d2efa1d83b2c08ae Mon Sep 17 00:00:00 2001
From: CyrusNajmabadi <cyrusn@microsoft.com>
Date: Tue, 15 Aug 2017 16:43:47 -0700
Subject: [PATCH 75/77] renamed methods.

---
 ...eDocCommentTextWithTagCodeRefactoringProvider.cs | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/src/Features/Core/Portable/ReplaceDocCommentTextWithTag/AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider.cs b/src/Features/Core/Portable/ReplaceDocCommentTextWithTag/AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
index 0a309b778a2fc..b35ae54b6afd5 100644
--- a/src/Features/Core/Portable/ReplaceDocCommentTextWithTag/AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
+++ b/src/Features/Core/Portable/ReplaceDocCommentTextWithTag/AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
@@ -2,6 +2,7 @@
 
 using System;
 using System.Composition;
+using System.Diagnostics;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
@@ -171,12 +172,14 @@ private TextSpan ExpandSpan(SourceText sourceText, TextSpan span, bool fullyQual
 
             var start = span.Start;
             var end = span.Start;
-            while (start > 0 && ExpandBackward(sourceText, start, fullyQualifiedName))
+            while (start > 0 &&
+                   ShouldExpandSpanBackwardOneCharacter(sourceText, start, fullyQualifiedName))
             {
                 start--;
             }
 
-            while (end < sourceText.Length && ExpandForward(sourceText, end, fullyQualifiedName))
+            while (end < sourceText.Length && 
+                   ShouldExpandSpanForwardOneCharacter(sourceText, end, fullyQualifiedName))
             {
                 end++;
             }
@@ -184,7 +187,7 @@ private TextSpan ExpandSpan(SourceText sourceText, TextSpan span, bool fullyQual
             return TextSpan.FromBounds(start, end);
         }
 
-        private bool ExpandForward(SourceText sourceText, int end, bool fullyQualifiedName)
+        private bool ShouldExpandSpanForwardOneCharacter(SourceText sourceText, int end, bool fullyQualifiedName)
         {
             var currentChar = sourceText[end];
 
@@ -204,9 +207,11 @@ private bool ExpandForward(SourceText sourceText, int end, bool fullyQualifiedNa
             return false;
         }
 
-        private bool ExpandBackward(
+        private bool ShouldExpandSpanBackwardOneCharacter(
             SourceText sourceText, int start, bool fullyQualifiedName)
         {
+            Debug.Assert(start > 0);
+
             var previousCharacter = sourceText[start - 1];
             if (char.IsLetterOrDigit(previousCharacter))
             {

From 794be07d178fe870912191929fe8f32539171709 Mon Sep 17 00:00:00 2001
From: CyrusNajmabadi <cyrusn@microsoft.com>
Date: Tue, 15 Aug 2017 16:44:37 -0700
Subject: [PATCH 76/77] Rename parameters.

---
 ...mmentTextWithTagCodeRefactoringProvider.cs | 31 ++++++++++---------
 1 file changed, 16 insertions(+), 15 deletions(-)

diff --git a/src/Features/Core/Portable/ReplaceDocCommentTextWithTag/AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider.cs b/src/Features/Core/Portable/ReplaceDocCommentTextWithTag/AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
index b35ae54b6afd5..10dd83805044f 100644
--- a/src/Features/Core/Portable/ReplaceDocCommentTextWithTag/AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
+++ b/src/Features/Core/Portable/ReplaceDocCommentTextWithTag/AbstractReplaceDocCommentTextWithTagCodeRefactoringProvider.cs
@@ -170,26 +170,27 @@ private TextSpan ExpandSpan(SourceText sourceText, TextSpan span, bool fullyQual
                 return span;
             }
 
-            var start = span.Start;
-            var end = span.Start;
-            while (start > 0 &&
-                   ShouldExpandSpanBackwardOneCharacter(sourceText, start, fullyQualifiedName))
+            var startInclusive = span.Start;
+            var endExclusive = span.Start;
+            while (startInclusive > 0 &&
+                   ShouldExpandSpanBackwardOneCharacter(sourceText, startInclusive, fullyQualifiedName))
             {
-                start--;
+                startInclusive--;
             }
 
-            while (end < sourceText.Length && 
-                   ShouldExpandSpanForwardOneCharacter(sourceText, end, fullyQualifiedName))
+            while (endExclusive < sourceText.Length && 
+                   ShouldExpandSpanForwardOneCharacter(sourceText, endExclusive, fullyQualifiedName))
             {
-                end++;
+                endExclusive++;
             }
 
-            return TextSpan.FromBounds(start, end);
+            return TextSpan.FromBounds(startInclusive, endExclusive);
         }
 
-        private bool ShouldExpandSpanForwardOneCharacter(SourceText sourceText, int end, bool fullyQualifiedName)
+        private bool ShouldExpandSpanForwardOneCharacter(
+            SourceText sourceText, int endExclusive, bool fullyQualifiedName)
         {
-            var currentChar = sourceText[end];
+            var currentChar = sourceText[endExclusive];
 
             if (char.IsLetterOrDigit(currentChar))
             {
@@ -199,7 +200,7 @@ private bool ShouldExpandSpanForwardOneCharacter(SourceText sourceText, int end,
             // Only consume a dot in front of the current word if it is part of a dotted
             // word chain, and isn't just the end of a sentence.
             if (fullyQualifiedName && currentChar == '.' &&
-                end + 1 < sourceText.Length && char.IsLetterOrDigit(sourceText[end + 1]))
+                endExclusive + 1 < sourceText.Length && char.IsLetterOrDigit(sourceText[endExclusive + 1]))
             {
                 return true;
             }
@@ -208,11 +209,11 @@ private bool ShouldExpandSpanForwardOneCharacter(SourceText sourceText, int end,
         }
 
         private bool ShouldExpandSpanBackwardOneCharacter(
-            SourceText sourceText, int start, bool fullyQualifiedName)
+            SourceText sourceText, int startInclusive, bool fullyQualifiedName)
         {
-            Debug.Assert(start > 0);
+            Debug.Assert(startInclusive > 0);
 
-            var previousCharacter = sourceText[start - 1];
+            var previousCharacter = sourceText[startInclusive - 1];
             if (char.IsLetterOrDigit(previousCharacter))
             {
                 return true;

From 33459fff3166cea5dabb4da0521e710c0faaef3e Mon Sep 17 00:00:00 2001
From: Fredric Silberberg <frsilb@microsoft.com>
Date: Wed, 16 Aug 2017 17:47:26 -0700
Subject: [PATCH 77/77] Refactor variable names.

---
 ...actUseThrowExpressionDiagnosticAnalyzer.cs | 20 +++++++++----------
 1 file changed, 10 insertions(+), 10 deletions(-)

diff --git a/src/Features/Core/Portable/UseThrowExpression/AbstractUseThrowExpressionDiagnosticAnalyzer.cs b/src/Features/Core/Portable/UseThrowExpression/AbstractUseThrowExpressionDiagnosticAnalyzer.cs
index 2a4e212954cb9..6e85dd64feadf 100644
--- a/src/Features/Core/Portable/UseThrowExpression/AbstractUseThrowExpressionDiagnosticAnalyzer.cs
+++ b/src/Features/Core/Portable/UseThrowExpression/AbstractUseThrowExpressionDiagnosticAnalyzer.cs
@@ -77,14 +77,14 @@ private void AnalyzeOperation(OperationAnalysisContext context, INamedTypeSymbol
 
             var cancellationToken = context.CancellationToken;
 
-            var throwExpression = (IThrowExpression)context.Operation;
-            var throwStatementOperation = throwExpression.Parent;
+            var throwExpressionOperation = (IThrowExpression)context.Operation;
+            var throwStatementOperation = throwExpressionOperation.Parent;
             if (throwStatementOperation.Kind != OperationKind.ExpressionStatement)
             {
                 return;
             }
 
-            var throwStatement = throwExpression.Syntax;
+            var throwStatementSyntax = throwExpressionOperation.Syntax;
             var options = context.Options;
             var optionSet = options.GetDocumentOptionSetAsync(syntaxTree, cancellationToken).GetAwaiter().GetResult();
             if (optionSet == null)
@@ -92,16 +92,16 @@ private void AnalyzeOperation(OperationAnalysisContext context, INamedTypeSymbol
                 return;
             }
 
-            var option = optionSet.GetOption(CodeStyleOptions.PreferThrowExpression, throwStatement.Language);
+            var option = optionSet.GetOption(CodeStyleOptions.PreferThrowExpression, throwStatementSyntax.Language);
             if (!option.Value)
             {
                 return;
             }
 
             var compilation = context.Compilation;
-            var semanticModel = compilation.GetSemanticModel(throwStatement.SyntaxTree);
+            var semanticModel = compilation.GetSemanticModel(throwStatementSyntax.SyntaxTree);
             var semanticFacts = GetSemanticFactsService();
-            if (semanticFacts.IsInExpressionTree(semanticModel, throwStatement, expressionTypeOpt, cancellationToken))
+            if (semanticFacts.IsInExpressionTree(semanticModel, throwStatementSyntax, expressionTypeOpt, cancellationToken))
             {
                 return;
             }
@@ -165,18 +165,18 @@ private void AnalyzeOperation(OperationAnalysisContext context, INamedTypeSymbol
 
             var allLocations = ImmutableArray.Create(
                 ifOperation.Syntax.GetLocation(),
-                throwExpression.Expression.Syntax.GetLocation(),
+                throwExpressionOperation.Expression.Syntax.GetLocation(),
                 assignmentExpression.Value.Syntax.GetLocation());
 
             var descriptor = GetDescriptorWithSeverity(option.Notification.Value);
 
             context.ReportDiagnostic(
-                Diagnostic.Create(descriptor, throwStatement.GetLocation(), additionalLocations: allLocations));
+                Diagnostic.Create(descriptor, throwStatementSyntax.GetLocation(), additionalLocations: allLocations));
 
             // Fade out the rest of the if that surrounds the 'throw' exception.
 
-            var tokenBeforeThrow = throwStatement.GetFirstToken().GetPreviousToken();
-            var tokenAfterThrow = throwStatement.GetLastToken().GetNextToken();
+            var tokenBeforeThrow = throwStatementSyntax.GetFirstToken().GetPreviousToken();
+            var tokenAfterThrow = throwStatementSyntax.GetLastToken().GetNextToken();
             context.ReportDiagnostic(
                 Diagnostic.Create(UnnecessaryWithSuggestionDescriptor,
                     Location.Create(syntaxTree, TextSpan.FromBounds(