Optimized find all references and reduced memory usage in VS

eng/Versions.props

@@ -96,6 +96,7 @@
     <SystemThreadingThreadPoolVersion>4.3.0</SystemThreadingThreadPoolVersion>
     <SystemValueTupleVersion>4.5.0</SystemValueTupleVersion>
     <SystemBuffersVersion>4.5.0</SystemBuffersVersion>
+    <SystemMemoryVersion>4.5.3</SystemMemoryVersion>
     <!-- Roslyn packages -->
     <MicrosoftCodeAnalysisEditorFeaturesVersion>$(RoslynVersion)</MicrosoftCodeAnalysisEditorFeaturesVersion>
     <MicrosoftCodeAnalysisEditorFeaturesTextVersion>$(RoslynVersion)</MicrosoftCodeAnalysisEditorFeaturesTextVersion>

fcs/FSharp.Compiler.Service/FSharp.Compiler.Service.fsproj

@@ -573,6 +573,18 @@
     <Compile Include="$(FSharpSourcesRoot)\fsharp\service\Reactor.fs">
       <Link>Service/Reactor.fs</Link>
     </Compile>
+    <Compile Include="$(FSharpSourcesRoot)\fsharp\service\SemanticClassification.fsi">
+      <Link>Service/SemanticClassification.fsi</Link>
+    </Compile>
+    <Compile Include="$(FSharpSourcesRoot)\fsharp\service\SemanticClassification.fs">
+      <Link>Service/SemanticClassification.fs</Link>
+    </Compile>
+    <Compile Include="$(FSharpSourcesRoot)\fsharp\service\ItemKey.fsi">
+      <Link>Service/ItemKey.fsi</Link>
+    </Compile>
+    <Compile Include="$(FSharpSourcesRoot)\fsharp\service\ItemKey.fs">
+      <Link>Service/ItemKey.fs</Link>
+    </Compile>
     <Compile Include="$(FSharpSourcesRoot)\fsharp\service\IncrementalBuild.fsi">
       <Link>Service/IncrementalBuild.fsi</Link>
     </Compile>
@@ -681,6 +693,7 @@
     <PackageReference Include="System.Collections.Immutable" Version="1.5.0" />
     <PackageReference Include="System.Reflection.Metadata" Version="1.6.0" />
     <PackageReference Include="System.Buffers" Version="4.5.0" />
+    <PackageReference Include="System.Memory" Version="4.5.3" />
   </ItemGroup>
   <ItemGroup Condition="'$(TargetFramework)' == 'netstandard2.0'">
     <PackageReference Include="System.Diagnostics.Process" Version="4.1.0" />

src/fsharp/FSharp.Compiler.Private/FSharp.Compiler.Private.fsproj

@@ -28,6 +28,7 @@
       <BuiltProjectOutputGroupKeyOutput Include="$(BuildOutputGroupLocation)\System.Reflection.Metadata.dll" />
       <BuiltProjectOutputGroupKeyOutput Include="$(BuildOutputGroupLocation)\System.Collections.Immutable.dll" />
       <BuiltProjectOutputGroupKeyOutput Include="$(BuildOutputGroupLocation)\System.Buffers.dll" />
+      <BuiltProjectOutputGroupKeyOutput Include="$(BuildOutputGroupLocation)\System.Memory.dll" />
     </ItemGroup>
   </Target>
 
@@ -579,6 +580,18 @@
     </Compile>
 
     <!-- the incremental builder and service . -->
+    <Compile Include="..\service\SemanticClassification.fsi">
+      <Link>Service/SemanticClassification.fsi</Link>
+    </Compile>
+    <Compile Include="..\service\SemanticClassification.fs">
+      <Link>Service/SemanticClassification.fs</Link>
+    </Compile>
+    <Compile Include="..\service\ItemKey.fsi">
+      <Link>Service/ItemKey.fsi</Link>
+    </Compile>
+    <Compile Include="..\service\ItemKey.fs">
+      <Link>Service/ItemKey.fs</Link>
+    </Compile>
     <Compile Include="..\service\IncrementalBuild.fsi">
       <Link>Service/IncrementalBuild.fsi</Link>
     </Compile>
@@ -745,6 +758,7 @@
     <PackageReference Include="System.Threading.Thread" Version="$(SystemThreadingThreadVersion)" />
     <PackageReference Include="System.Threading.ThreadPool" Version="$(SystemThreadingThreadPoolVersion)" />
     <PackageReference Include="System.Buffers" Version="$(SystemBuffersVersion)" />
+    <PackageReference Include="System.Memory" Version="$(SystemMemoryVersion)" />
   </ItemGroup>
 
 </Project>

src/fsharp/FSharp.Compiler.Private/FSharp.Compiler.Private.netcore.nuspec

@@ -34,6 +34,7 @@
                 <dependency id="System.Threading.ThreadPool" version="4.0.10" />
                 <dependency id="System.ValueTuple" version="4.3.0" />
                 <dependency id="System.Buffers" version="4.5.0" />
+                <dependency id="System.Memory" version="4.5.3" />
             </group>
         </dependencies>
     </metadata>

src/fsharp/FSharp.Compiler.nuget/Microsoft.FSharp.Compiler.nuspec

@@ -23,6 +23,7 @@
                 <dependency id="System.Threading.ThreadPool" version="4.3.0" />
                 <dependency id="System.ValueTuple" version="4.4.0" />
                 <dependency id="System.Buffers" version="4.5.0" />
+                <dependency id="System.Memory" version="4.5.3" />
             </group>
         </dependencies>
         <contentFiles>

src/fsharp/NameResolution.fs

@@ -1757,6 +1757,9 @@ type TcResultsSinkImpl(g, ?sourceText: ISourceText) =
     member this.GetOpenDeclarations() =
         capturedOpenDeclarations |> Seq.distinctBy (fun x -> x.Range, x.AppliedScope, x.IsOwnNamespace) |> Seq.toArray
 
+    member this.GetFormatSpecifierLocations() =
+        capturedFormatSpecifierLocations.ToArray()
+
     interface ITypecheckResultsSink with
         member sink.NotifyEnvWithScope(m, nenv, ad) =
             if allowedRange m then

src/fsharp/NameResolution.fsi

@@ -438,6 +438,9 @@ type internal TcResultsSinkImpl =
     /// Get all open declarations reported to the sink
     member GetOpenDeclarations : unit -> OpenDeclaration[]
 
+    /// Get the format specifier locations
+    member GetFormatSpecifierLocations : unit -> (range * int)[]
+
     interface ITypecheckResultsSink
 
 /// An abstract type for reporting the results of name resolution and type checking, and which allows

src/fsharp/lexhelp.fs

@@ -36,8 +36,8 @@ type LightSyntaxStatus(initial:bool,warn:bool) =
 
 /// Manage lexer resources (string interning)
 [<Sealed>]
-type LexResourceManager() =
-    let strings = new System.Collections.Generic.Dictionary<string, Parser.token>(1024)
+type LexResourceManager(?capacity: int) =
+    let strings = new System.Collections.Generic.Dictionary<string, Parser.token>(defaultArg capacity 1024)
     member x.InternIdentifierToken(s) = 
         match strings.TryGetValue s with
         | true, res -> res

src/fsharp/lexhelp.fsi

@@ -25,7 +25,7 @@ type LightSyntaxStatus =
 
 [<Sealed>]
 type LexResourceManager =
-    new : unit -> LexResourceManager
+    new : ?capacity: int -> LexResourceManager
 
 type lexargs =
     { defines: string list

src/fsharp/service/FSharpCheckerResults.fs

@@ -109,24 +109,6 @@ type GetPreciseCompletionListFromExprTypingsResult =
     | Some of (ItemWithInst list * DisplayEnv * range) * TType
 
 type Names = string list 
-
-[<RequireQualifiedAccess>]
-type SemanticClassificationType =
-    | ReferenceType
-    | ValueType
-    | UnionCase
-    | Function
-    | Property
-    | MutableVar
-    | Module
-    | Printf
-    | ComputationExpression
-    | IntrinsicFunction
-    | Enumeration
-    | Interface
-    | TypeArgument
-    | Operator
-    | Disposable
 
 /// A TypeCheckInfo represents everything we get back from the typecheck of a file.
 /// It acts like an in-memory database about the file.
@@ -155,8 +137,6 @@ type internal TypeCheckInfo
            openDeclarations: OpenDeclaration[]) = 
 
     let textSnapshotInfo = defaultArg textSnapshotInfo null
-    let (|CNR|) (cnr:CapturedNameResolution) =
-        (cnr.Pos, cnr.Item, cnr.ItemOccurence, cnr.DisplayEnv, cnr.NameResolutionEnv, cnr.AccessorDomain, cnr.Range)
 
     // These strings are potentially large and the editor may choose to hold them for a while.
     // Use this cache to fold together data tip text results that are the same. 
@@ -1262,133 +1242,8 @@ type internal TypeCheckInfo
     member __.GetFormatSpecifierLocationsAndArity() = 
          sSymbolUses.GetFormatSpecifierLocationsAndArity()
 
-    member __.GetSemanticClassification(range: range option) : (range * SemanticClassificationType) [] =
-      ErrorScope.Protect Range.range0 
-       (fun () -> 
-        let (|LegitTypeOccurence|_|) = function
-            | ItemOccurence.UseInType
-            | ItemOccurence.UseInAttribute
-            | ItemOccurence.Use _
-            | ItemOccurence.Binding _
-            | ItemOccurence.Pattern _ -> Some()
-            | _ -> None
-
-        let (|OptionalArgumentAttribute|_|) ttype =
-            match ttype with
-            | TType.TType_app(tref, _) when tref.Stamp = g.attrib_OptionalArgumentAttribute.TyconRef.Stamp -> Some()
-            | _ -> None
-
-        let (|KeywordIntrinsicValue|_|) (vref: ValRef) =
-            if valRefEq g g.raise_vref vref ||
-               valRefEq g g.reraise_vref vref ||
-               valRefEq g g.typeof_vref vref ||
-               valRefEq g g.typedefof_vref vref ||
-               valRefEq g g.sizeof_vref vref ||
-               valRefEq g g.nameof_vref vref
-            then Some()
-            else None
-
-        let (|EnumCaseFieldInfo|_|) (rfinfo : RecdFieldInfo) =
-            match rfinfo.TyconRef.TypeReprInfo with
-            | TFSharpObjectRepr x ->
-                match x.fsobjmodel_kind with
-                | TTyconEnum -> Some ()
-                | _ -> None
-            | _ -> None
-
-        let resolutions =
-            match range with
-            | Some range ->
-                sResolutions.CapturedNameResolutions
-                |> Seq.filter (fun cnr -> rangeContainsPos range cnr.Range.Start || rangeContainsPos range cnr.Range.End)
-            | None -> 
-                sResolutions.CapturedNameResolutions :> seq<_>
-
-        let isDisposableTy (ty: TType) =
-            protectAssemblyExplorationNoReraise false false (fun () -> Infos.ExistsHeadTypeInEntireHierarchy g amap range0 ty g.tcref_System_IDisposable)
-
-        let isStructTyconRef (tyconRef: TyconRef) = 
-            let ty = generalizedTyconRef tyconRef
-            let underlyingTy = stripTyEqnsAndMeasureEqns g ty
-            isStructTy g underlyingTy
-
-        let isValRefMutable (vref: ValRef) =
-            // Mutable values, ref cells, and non-inref byrefs are mutable.
-            vref.IsMutable
-            || Tastops.isRefCellTy g vref.Type
-            || (Tastops.isByrefTy g vref.Type && not (Tastops.isInByrefTy g vref.Type))
-
-        let isRecdFieldMutable (rfinfo: RecdFieldInfo) =
-            (rfinfo.RecdField.IsMutable && rfinfo.LiteralValue.IsNone)
-            || Tastops.isRefCellTy g rfinfo.RecdField.FormalType
-
-        resolutions
-        |> Seq.choose (fun cnr ->
-            match cnr with
-            // 'seq' in 'seq { ... }' gets colored as keywords
-            | CNR(_, (Item.Value vref), ItemOccurence.Use, _, _, _, m) when valRefEq g g.seq_vref vref ->
-                Some (m, SemanticClassificationType.ComputationExpression)
-            | CNR(_, (Item.Value vref), _, _, _, _, m) when isValRefMutable vref ->
-                Some (m, SemanticClassificationType.MutableVar)
-            | CNR(_, Item.Value KeywordIntrinsicValue, ItemOccurence.Use, _, _, _, m) ->
-                Some (m, SemanticClassificationType.IntrinsicFunction)
-            | CNR(_, (Item.Value vref), _, _, _, _, m) when isFunction g vref.Type ->
-                if valRefEq g g.range_op_vref vref || valRefEq g g.range_step_op_vref vref then 
-                    None
-                elif vref.IsPropertyGetterMethod || vref.IsPropertySetterMethod then
-                    Some (m, SemanticClassificationType.Property)
-                elif IsOperatorName vref.DisplayName then
-                    Some (m, SemanticClassificationType.Operator)
-                else
-                    Some (m, SemanticClassificationType.Function)
-            | CNR(_, Item.RecdField rfinfo, _, _, _, _, m) when isRecdFieldMutable rfinfo ->
-                Some (m, SemanticClassificationType.MutableVar)
-            | CNR(_, Item.RecdField rfinfo, _, _, _, _, m) when isFunction g rfinfo.FieldType ->
-               Some (m, SemanticClassificationType.Function)
-            | CNR(_, Item.RecdField EnumCaseFieldInfo, _, _, _, _, m) ->
-                Some (m, SemanticClassificationType.Enumeration)
-            | CNR(_, Item.MethodGroup _, _, _, _, _, m) ->
-                Some (m, SemanticClassificationType.Function)
-            // custom builders, custom operations get colored as keywords
-            | CNR(_, (Item.CustomBuilder _ | Item.CustomOperation _), ItemOccurence.Use, _, _, _, m) ->
-                Some (m, SemanticClassificationType.ComputationExpression)
-            // types get colored as types when they occur in syntactic types or custom attributes
-            // type variables get colored as types when they occur in syntactic types custom builders, custom operations get colored as keywords
-            | CNR(_, Item.Types (_, [OptionalArgumentAttribute]), LegitTypeOccurence, _, _, _, _) -> None
-            | CNR(_, Item.CtorGroup(_, [MethInfo.FSMeth(_, OptionalArgumentAttribute, _, _)]), LegitTypeOccurence, _, _, _, _) -> None
-            | CNR(_, Item.Types(_, types), LegitTypeOccurence, _, _, _, m) when types |> List.exists (isInterfaceTy g) -> 
-                Some (m, SemanticClassificationType.Interface)
-            | CNR(_, Item.Types(_, types), LegitTypeOccurence, _, _, _, m) when types |> List.exists (isStructTy g) -> 
-                Some (m, SemanticClassificationType.ValueType)
-            | CNR(_, Item.Types(_, TType_app(tyconRef, TType_measure _ :: _) :: _), LegitTypeOccurence, _, _, _, m) when isStructTyconRef tyconRef ->
-                Some (m, SemanticClassificationType.ValueType)
-            | CNR(_, Item.Types(_, types), LegitTypeOccurence, _, _, _, m) when types |> List.exists isDisposableTy ->
-                Some (m, SemanticClassificationType.Disposable)
-            | CNR(_, Item.Types _, LegitTypeOccurence, _, _, _, m) -> 
-                Some (m, SemanticClassificationType.ReferenceType)
-            | CNR(_, (Item.TypeVar _ ), LegitTypeOccurence, _, _, _, m) ->
-                Some (m, SemanticClassificationType.TypeArgument)
-            | CNR(_, Item.UnqualifiedType tyconRefs, LegitTypeOccurence, _, _, _, m) ->
-                if tyconRefs |> List.exists (fun tyconRef -> tyconRef.Deref.IsStructOrEnumTycon) then
-                    Some (m, SemanticClassificationType.ValueType)
-                else Some (m, SemanticClassificationType.ReferenceType)
-            | CNR(_, Item.CtorGroup(_, minfos), LegitTypeOccurence, _, _, _, m) ->
-                if minfos |> List.exists (fun minfo -> isStructTy g minfo.ApparentEnclosingType) then
-                    Some (m, SemanticClassificationType.ValueType)
-                else Some (m, SemanticClassificationType.ReferenceType)
-            | CNR(_, Item.ExnCase _, LegitTypeOccurence, _, _, _, m) ->
-                Some (m, SemanticClassificationType.ReferenceType)
-            | CNR(_, Item.ModuleOrNamespaces refs, LegitTypeOccurence, _, _, _, m) when refs |> List.exists (fun x -> x.IsModule) ->
-                Some (m, SemanticClassificationType.Module)
-            | CNR(_, (Item.ActivePatternCase _ | Item.UnionCase _ | Item.ActivePatternResult _), _, _, _, _, m) ->
-                Some (m, SemanticClassificationType.UnionCase)
-            | _ -> None)
-        |> Seq.toArray
-        |> Array.append (sSymbolUses.GetFormatSpecifierLocationsAndArity() |> Array.map (fun m -> fst m, SemanticClassificationType.Printf))
-       ) 
-       (fun msg -> 
-           Trace.TraceInformation(sprintf "FCS: recovering from error in GetSemanticClassification: '%s'" msg)
-           Array.empty)
+    member __.GetSemanticClassification(range: range option) : struct (range * SemanticClassificationType) [] =
+        sResolutions.GetSemanticClassification(g, amap, sSymbolUses.GetFormatSpecifierLocationsAndArity(), range)
 
     /// The resolutions in the file
     member __.ScopeResolutions = sResolutions

src/fsharp/service/FSharpCheckerResults.fsi

@@ -56,24 +56,6 @@ type public FSharpProjectContext =
     /// Get the accessibility rights for this project context w.r.t. InternalsVisibleTo attributes granting access to other assemblies
     member AccessibilityRights : FSharpAccessibilityRights
 
-[<RequireQualifiedAccess>]
-type public SemanticClassificationType =
-    | ReferenceType
-    | ValueType
-    | UnionCase
-    | Function
-    | Property
-    | MutableVar
-    | Module
-    | Printf
-    | ComputationExpression
-    | IntrinsicFunction
-    | Enumeration
-    | Interface
-    | TypeArgument
-    | Operator
-    | Disposable
-
 /// Options used to determine active --define conditionals and other options relevant to parsing files in a project
 type public FSharpParsingOptions =
     { 
@@ -234,7 +216,7 @@ type public FSharpCheckFileResults =
     member GetSymbolUseAtLocation  : line:int * colAtEndOfNames:int * lineText:string * names:string list * ?userOpName: string -> Async<FSharpSymbolUse option>
 
     /// <summary>Get any extra colorization info that is available after the typecheck</summary>
-    member GetSemanticClassification : range option -> (range * SemanticClassificationType)[]
+    member GetSemanticClassification : range option -> struct (range * SemanticClassificationType)[]
 
     /// <summary>Get the locations of format specifiers</summary>
     [<System.Obsolete("This member has been replaced by GetFormatSpecifierLocationsAndArity, which returns both range and arity of specifiers")>]