Merge master into live

docs/core/diagnostics/debug-memory-leak.md

@@ -140,7 +140,7 @@ dotnet-dump analyze core_20190430_185145
 Where `core_20190430_185145` is the name of the core dump you want to analyze.
 
 > [!NOTE]
-> If you see an error complaining that *libdl.so* cannot be found, you may have to install the *libc6-dev* package. For more information, see [Prerequisites for .NET Core on Linux](../linux-prerequisites.md).
+> If you see an error complaining that *libdl.so* cannot be found, you may have to install the *libc6-dev* package. For more information, see [Prerequisites for .NET Core on Linux](../install/dependencies.md?pivots=os-linux).
 
 You'll be presented with a prompt where you can enter SOS commands. Commonly, the first thing you want to look at is the overall state of the managed heap:
 

docs/core/install/how-to-detect-installed-versions.md

@@ -161,6 +161,51 @@ Microsoft.NETCore.App 3.1.0 [/usr/local/share/dotnet/shared/Microsoft.NETCore.Ap
 
 ::: zone-end
 
+## Check for install folders
+
+It's possible that .NET Core is installed but not added to the `PATH` variable for your operating system or user profile. Running the commands from the previous sections may not work. As an alternative, you can check that the .NET Core install folders exist.
+
+When you install .NET Core from an installer or script, it's installed to a standard folder. Much of the time the installer or script you're using to install .NET Core gives you an option to install to a different folder. If you choose to install to a different folder, adjust the start of the folder path.
+
+::: zone pivot="os-windows"
+
+- **dotnet executable**\
+_C:\\program files\\dotnet\\dotnet.exe_
+
+- **.NET SDK**\
+_C:\\program files\\dotnet\\sdk\\{version}\\_
+
+- **.NET Runtime**\
+_C:\\program files\\dotnet\\shared\\{runtime-type}\\{version}\\_
+
+::: zone-end
+
+::: zone pivot="os-linux"
+
+- **dotnet executable**\
+_/home/user/share/dotnet/dotnet_
+
+- **.NET SDK**\
+_/home/user/share/dotnet/sdk/{version}/_
+
+- **.NET Runtime**\
+_/home/user/share/dotnet/shared/{runtime-type}/{version}/_
+
+::: zone-end
+
+::: zone pivot="os-macos"
+
+- **dotnet executable**\
+_/usr/local/share/dotnet/dotnet_
+
+- **.NET SDK**\
+_/usr/local/share/dotnet/sdk/{version}/_
+
+- **.NET Runtime**\
+_/usr/local/share/dotnet/shared/{runtime-type}/{version}/_
+
+::: zone-end
+
 ## More information
 
 You can see both the SDK versions and runtime versions with the command `dotnet --info`. You'll also get other environmental related information, such as the operating system version and runtime identifier (RID).

docs/core/install/linux-package-manager-centos7.md

@@ -14,12 +14,12 @@ This article describes how to use a package manager to install .NET Core on Cent
 
 [!INCLUDE [package-manager-intro-sdk-vs-runtime](includes/package-manager-intro-sdk-vs-runtime.md)]
 
-## Register Microsoft key and feed
+## Add Microsoft repository key and feed
 
 Before installing .NET, you'll need to:
 
-- Register the Microsoft key.
-- Register the product repository.
+- Add the Microsoft package signing key to the list of trusted keys.
+- Add the repository to the package manager.
 - Install required dependencies.
 
 This only needs to be done once per machine.

docs/core/install/linux-package-manager-debian10.md

@@ -14,12 +14,12 @@ This article describes how to use a package manager to install .NET Core on Debi
 
 [!INCLUDE [package-manager-intro-sdk-vs-runtime](includes/package-manager-intro-sdk-vs-runtime.md)]
 
-## Register Microsoft key and feed
+## Add Microsoft repository key and feed
 
 Before installing .NET, you'll need to:
 
-- Register the Microsoft key.
-- Register the product repository.
+- Add the Microsoft package signing key to the list of trusted keys.
+- Add the repository to the package manager.
 - Install required dependencies.
 
 This only needs to be done once per machine.

docs/core/install/linux-package-manager-debian9.md

@@ -14,12 +14,12 @@ This article describes how to use a package manager to install .NET Core on Debi
 
 [!INCLUDE [package-manager-intro-sdk-vs-runtime](includes/package-manager-intro-sdk-vs-runtime.md)]
 
-## Register Microsoft key and feed
+## Add Microsoft repository key and feed
 
 Before installing .NET, you'll need to:
 
-- Register the Microsoft key.
-- Register the product repository.
+- Add the Microsoft package signing key to the list of trusted keys.
+- Add the repository to the package manager.
 - Install required dependencies.
 
 This only needs to be done once per machine.

docs/core/install/linux-package-manager-fedora29.md

@@ -14,12 +14,12 @@ This article describes how to use a package manager to install .NET Core on Fedo
 
 [!INCLUDE [package-manager-intro-sdk-vs-runtime](includes/package-manager-intro-sdk-vs-runtime.md)]
 
-## Register Microsoft key and feed
+## Add Microsoft repository key and feed
 
 Before installing .NET, you'll need to:
 
-- Register the Microsoft key.
-- Register the product repository.
+- Add the Microsoft package signing key to the list of trusted keys.
+- Add the repository to the package manager.
 - Install required dependencies.
 
 This only needs to be done once per machine.

docs/core/install/linux-package-manager-fedora30.md

@@ -14,12 +14,12 @@ This article describes how to use a package manager to install .NET Core on Fedo
 
 [!INCLUDE [package-manager-intro-sdk-vs-runtime](includes/package-manager-intro-sdk-vs-runtime.md)]
 
-## Register Microsoft key and feed
+## Add Microsoft repository key and feed
 
 Before installing .NET, you'll need to:
 
-- Register the Microsoft key.
-- Register the product repository.
+- Add the Microsoft package signing key to the list of trusted keys.
+- Add the repository to the package manager.
 - Install required dependencies.
 
 This only needs to be done once per machine.

docs/core/install/linux-package-manager-fedora31.md

@@ -14,12 +14,12 @@ This article describes how to use a package manager to install .NET Core on Fedo
 
 [!INCLUDE [package-manager-intro-sdk-vs-runtime](includes/package-manager-intro-sdk-vs-runtime.md)]
 
-## Register Microsoft key and feed
+## Add Microsoft repository key and feed
 
 Before installing .NET, you'll need to:
 
-- Register the Microsoft key.
-- Register the product repository.
+- Add the Microsoft package signing key to the list of trusted keys.
+- Add the repository to the package manager.
 - Install required dependencies.
 
 This only needs to be done once per machine.

docs/core/install/linux-package-manager-opensuse15.md

@@ -14,12 +14,12 @@ This article describes how to use a package manager to install .NET Core on open
 
 [!INCLUDE [package-manager-intro-sdk-vs-runtime](includes/package-manager-intro-sdk-vs-runtime.md)]
 
-## Register Microsoft key and feed
+## Add Microsoft repository key and feed
 
 Before installing .NET, you'll need to:
 
-- Register the Microsoft key.
-- Register the product repository.
+- Add the Microsoft package signing key to the list of trusted keys.
+- Add the repository to the package manager.
 - Install required dependencies.
 
 This only needs to be done once per machine.

docs/core/install/linux-package-manager-sles12.md

@@ -14,12 +14,12 @@ This article describes how to use a package manager to install .NET Core on SLES
 
 [!INCLUDE [package-manager-intro-sdk-vs-runtime](includes/package-manager-intro-sdk-vs-runtime.md)]
 
-## Register Microsoft key and feed
+## Add Microsoft repository key and feed
 
 Before installing .NET, you'll need to:
 
-- Register the Microsoft key.
-- Register the product repository.
+- Add the Microsoft package signing key to the list of trusted keys.
+- Add the repository to the package manager.
 - Install required dependencies.
 
 This only needs to be done once per machine.

docs/core/install/linux-package-manager-sles15.md

@@ -14,12 +14,12 @@ This article describes how to use a package manager to install .NET Core on SLES
 
 [!INCLUDE [package-manager-intro-sdk-vs-runtime](includes/package-manager-intro-sdk-vs-runtime.md)]
 
-## Register Microsoft key and feed
+## Add Microsoft repository key and feed
 
 Before installing .NET, you'll need to:
 
-- Register the Microsoft key.
-- Register the product repository.
+- Add the Microsoft package signing key to the list of trusted keys.
+- Add the repository to the package manager.
 - Install required dependencies.
 
 This only needs to be done once per machine.

docs/core/install/linux-package-manager-ubuntu-1604.md

@@ -14,12 +14,12 @@ This article describes how to use a package manager to install .NET Core on Ubun
 
 [!INCLUDE [package-manager-intro-sdk-vs-runtime](includes/package-manager-intro-sdk-vs-runtime.md)]
 
-## Register Microsoft key and feed
+## Add Microsoft repository key and feed
 
 Before installing .NET, you'll need to:
 
-- Register the Microsoft key.
-- Register the product repository.
+- Add the Microsoft package signing key to the list of trusted keys.
+- Add the repository to the package manager.
 - Install required dependencies.
 
 This only needs to be done once per machine.

docs/core/install/linux-package-manager-ubuntu-1804.md

@@ -14,12 +14,12 @@ This article describes how to use a package manager to install .NET Core on Ubun
 
 [!INCLUDE [package-manager-intro-sdk-vs-runtime](includes/package-manager-intro-sdk-vs-runtime.md)]
 
-## Register Microsoft key and feed
+## Add Microsoft repository key and feed
 
 Before installing .NET, you'll need to:
 
-- Register the Microsoft key.
-- Register the product repository.
+- Add the Microsoft package signing key to the list of trusted keys.
+- Add the repository to the package manager.
 - Install required dependencies.
 
 This only needs to be done once per machine.

docs/core/install/linux-package-manager-ubuntu-1904.md

@@ -14,12 +14,12 @@ This article describes how to use a package manager to install .NET Core on Ubun
 
 [!INCLUDE [package-manager-intro-sdk-vs-runtime](includes/package-manager-intro-sdk-vs-runtime.md)]
 
-## Register Microsoft key and feed
+## Add Microsoft repository key and feed
 
 Before installing .NET, you'll need to:
 
-- Register the Microsoft key.
-- Register the product repository.
+- Add the Microsoft package signing key to the list of trusted keys.
+- Add the repository to the package manager.
 - Install required dependencies.
 
 This only needs to be done once per machine.

docs/core/install/linux-package-manager-ubuntu-1910.md

@@ -14,12 +14,12 @@ This article describes how to use a package manager to install .NET Core on Ubun
 
 [!INCLUDE [package-manager-intro-sdk-vs-runtime](includes/package-manager-intro-sdk-vs-runtime.md)]
 
-## Register Microsoft key and feed
+## Add Microsoft repository key and feed
 
 Before installing .NET, you'll need to:
 
-- Register the Microsoft key.
-- Register the product repository.
+- Add the Microsoft package signing key to the list of trusted keys.
+- Add the repository to the package manager.
 - Install required dependencies.
 
 This only needs to be done once per machine.

docs/core/introduction.md

@@ -7,7 +7,7 @@ ms.custom: "updateeachrelease"
 ---
 # Introduction to .NET Core
 
-[.NET Core](about.md) is an [open-source](https://github.com/dotnet/runtime/blob/master/LICENSE.TXT), general-purpose development platform. You can create .NET Core apps for Windows, macOS, and Linux for x64, x86, ARM32, and ARM64 processors using multiple programming languages. Frameworks and APIs are provided for [cloud](/aspnet/core/), [IoT](/archive/msdn-magazine/2019/august/net-core-cross-platform-iot-programming-with-net-core-3-0), [client UI](/dotnet/desktop-wpf/overview/index), and [machine learning](/dotnet/machine-learning/).
+[.NET Core](about.md) is an [open-source](https://github.com/dotnet/runtime/blob/master/LICENSE.TXT), general-purpose development platform. You can create .NET Core apps for Windows, macOS, and Linux for x64, x86, ARM32, and ARM64 processors using multiple programming languages. Frameworks and APIs are provided for [cloud](/aspnet/core/), [IoT](/archive/msdn-magazine/2019/august/net-core-cross-platform-iot-programming-with-net-core-3-0), [client UI](../desktop-wpf/overview/index.md), and [machine learning](/dotnet/machine-learning/).
 
 [Download the .NET Core SDK](https://dotnet.microsoft.com/download) to try .NET Core on your machine. The latest version is [.NET Core 3.1](https://devblogs.microsoft.com/dotnet/announcing-net-core-3-1/).
 

docs/core/toc.yml

@@ -351,7 +351,7 @@
   - name: Port Windows Forms projects
     href: porting/winforms.md
   - name: Port WPF projects
-    href: porting/wpf.md
+    href: ../desktop-wpf/migration/convert-project-from-net-framework.md
   - name: Port C++/CLI projects
     href: porting/cpp-cli.md
 - name: Unit testing
@@ -418,7 +418,7 @@
     - name: Create a .NET Core application with plugins
       href: tutorials/creating-app-with-plugin-support.md
     - name: How to use and debug assembly unloadability in .NET Core
-      href: ../standard/assembly/unloadability-howto.md
+      href: ../standard/assembly/unloadability.md
 - name: .NET Core distribution packaging
   href: distribution-packaging.md
 - name: Expose .NET Core components to COM

docs/core/versions/index.md

@@ -102,7 +102,7 @@ Each version of .NET Core implements a version of .NET Standard. Implementing a
 ## See also
 
 - [Target frameworks](../../standard/frameworks.md)
-- [.NET Core distribution packaging](../build/distribution-packaging.md)
+- [.NET Core distribution packaging](../distribution-packaging.md)
 - [.NET Core Support Lifecycle Fact Sheet](https://dotnet.microsoft.com/platform/support/policy)
 - [.NET Core 2+ Version Binding](https://github.com/dotnet/designs/issues/3)
 - [Docker images for .NET Core](https://hub.docker.com/_/microsoft-dotnet-core/)

docs/core/whats-new/dotnet-core-2-1.md

@@ -245,6 +245,6 @@ For information about breaking changes, see [Breaking changes for migration from
 
 ## See also
 
-- [What's new in .NET Core](index.md)
+- [What's new in .NET Core 3.1](dotnet-core-3-1.md)
 - [New features in EF Core 2.1](/ef/core/what-is-new/ef-core-2.1)
 - [What's new in ASP.NET Core 2.1](/aspnet/core/aspnetcore-2.1)

docs/core/whats-new/dotnet-core-2-2.md

@@ -91,6 +91,6 @@ See [Host startup hook](https://github.com/dotnet/core-setup/blob/master/Documen
 
 ## See also
 
-- [What's new in .NET Core](index.md)
+- [What's new in .NET Core 3.1](dotnet-core-3-1.md)
 - [What's new in ASP.NET Core 2.2](/aspnet/core/release-notes/aspnetcore-2.2)
 - [New features in EF Core 2.2](/ef/core/what-is-new/ef-core-2.2)

docs/csharp/language-reference/builtin-types/snippets/NullableValueTypes.cs

@@ -28,7 +28,7 @@ private static void DeclareAndAssign()
             int? m = m2;
 
             bool? flag = null;
-            
+
             // An array of a nullable value type:
             int?[] arr = new int?[10];
             // </SnippetDeclaration>

docs/csharp/language-reference/builtin-types/snippets/VoidType.cs

@@ -17,7 +17,7 @@ public static void Display(IEnumerable<int> numbers)
             {
                 return;
             }
-            
+
             Console.WriteLine(string.Join(" ", numbers));
         }
         // </SnippetVoidExample>

docs/csharp/language-reference/compiler-messages/cs0618.md

@@ -10,7 +10,7 @@ ms.assetid: b6edf0a9-b186-4ed8-9e16-978659b89205
 # Compiler Warning (level 2) CS0618
 'member' is obsolete: 'text'  
 
- A class member was marked with the `Obsolete` attribute, such that a warning will be issued when the class member is referenced. For more information, see [Common Attributes](../../programming-guide/concepts/attributes/common-attributes.md).  
+ A class member was marked with the `Obsolete` attribute, such that a warning will be issued when the class member is referenced. For more information, see [Common Attributes](../attributes/global.md).  
 
  The following sample generates CS0618:  
 

docs/csharp/language-reference/compiler-options/target-compiler-option.md

@@ -31,7 +31,7 @@ The **-target** compiler option can be specified in one of four forms:
  [-target:winmdobj](./target-winmdobj-compiler-option.md)  
  To create an intermediate .winmdobj file.  
 
- Unless you specify **-target:module**, **-target** causes a .NET Framework assembly manifest to be placed in an output file. For more information, see [Assemblies in .NET](../../../standard/assembly/index.md) and [Common Attributes](../../programming-guide/concepts/attributes/common-attributes.md).  
+ Unless you specify **-target:module**, **-target** causes a .NET Framework assembly manifest to be placed in an output file. For more information, see [Assemblies in .NET](../../../standard/assembly/index.md) and [Common Attributes](../attributes/global.md).  
 
  The assembly manifest is placed in the first .exe output file in the compilation or in the first DLL, if there is no .exe output file. For example, in the following command line, the manifest will be placed in `1.exe`:  
 

docs/csharp/language-reference/operators/member-access-operators.md

@@ -1,7 +1,7 @@
 ---
 title: "Member access operators and expressions - C# reference"
 description: "Learn about C# operators that you can use to access type members."
-ms.date: 03/31/2020
+ms.date: 04/17/2020
 author: pkulikov
 f1_keywords: 
   - "._CSharpKeyword"
@@ -150,6 +150,8 @@ if (handler != null)
 }
 ```
 
+That is a thread-safe way to ensure that only a non-null `handler` is invoked. Because delegate instances are immutable, no thread can change the value referenced by the `handler` local variable. In particular, if the code executed by another thread unsubscribes from the `PropertyChanged` event and `PropertyChanged` becomes `null` before `handler` is invoked, the value referenced by `handler` remains unaffected. The `?.` operator evaluates its left-hand operand no more than once, guaranteeing that it cannot be changed to `null` after being verified as non-null.
+
 ## Invocation expression ()
 
 Use parentheses, `()`, to call a [method](../../programming-guide/classes-and-structs/methods.md) or invoke a [delegate](../../programming-guide/delegates/index.md).

docs/csharp/language-reference/operators/snippets/AdditionOperator.cs

@@ -64,7 +64,7 @@ private static void AddAndAssign()
 
             Action printer = () => Console.Write("a");
             printer();  // output: a
-            
+
             Console.WriteLine();
             printer += () => Console.Write("b");
             printer();  // output: ab