TypeApp, type parameter completions (#12933)

src/fsharp/NameResolution.fs

@@ -4364,7 +4364,15 @@ let rec ResolvePartialLongIdentPrim (ncenv: NameResolver) (nenv: NameResolutionE
            |> Seq.collect (InfosForTyconConstructors ncenv m ad)
            |> Seq.toList
 
-       unqualifiedItems @ activePatternItems @ moduleAndNamespaceItems @ tycons @ constructors
+       let typeVars =
+           if nenv.eTypars.IsEmpty then
+               []
+           else
+               nenv.eTypars
+               |> Seq.map (fun kvp -> Item.TypeVar (kvp.Key, kvp.Value))
+               |> Seq.toList
+
+       unqualifiedItems @ activePatternItems @ moduleAndNamespaceItems @ tycons @ constructors @ typeVars
 
     | id :: rest ->
 

src/fsharp/NicePrint.fs

@@ -650,12 +650,13 @@ module PrintTypes =
         | _, _ -> squareAngleL (sepListL (rightL (tagPunctuation ";")) ((match kind with TyparKind.Type -> [] | TyparKind.Measure -> [wordL (tagText "Measure")]) @ List.map (layoutAttrib denv) attrs)) ^^ restL
 
     and layoutTyparRef denv (typar: Typar) =
-        wordL
-            (tagTypeParameter 
-                (sprintf "%s%s%s"
-                    (if denv.showConstraintTyparAnnotations then prefixOfStaticReq typar.StaticReq else "'")
-                    (if denv.showImperativeTyparAnnotations then prefixOfRigidTypar typar else "")
-                    typar.DisplayName))
+        tagTypeParameter 
+            (sprintf "%s%s%s"
+                (if denv.showConstraintTyparAnnotations then prefixOfStaticReq typar.StaticReq else "'")
+                (if denv.showImperativeTyparAnnotations then prefixOfRigidTypar typar else "")
+                typar.DisplayName)
+        |> mkNav typar.Range
+        |> wordL
 
     /// Layout a single type parameter declaration, taking TypeSimplificationInfo into account
     /// There are several printing-cases for a typar:
@@ -2426,6 +2427,8 @@ let prettyLayoutOfType denv x = x |> PrintTypes.prettyLayoutOfType denv
 
 let prettyLayoutOfTypeNoCx denv x = x |> PrintTypes.prettyLayoutOfTypeNoConstraints denv
 
+let prettyLayoutOfTypar denv x = x |> PrintTypes.layoutTyparRef denv
+
 let prettyStringOfTy denv x = x |> PrintTypes.prettyLayoutOfType denv |> showL
 
 let prettyStringOfTyNoCx denv x = x |> PrintTypes.prettyLayoutOfTypeNoConstraints denv |> showL

src/fsharp/NicePrint.fsi

@@ -87,6 +87,8 @@ val prettyLayoutOfType: denv:DisplayEnv -> x:TType -> Layout
 
 val prettyLayoutOfTypeNoCx: denv:DisplayEnv -> x:TType -> Layout
 
+val prettyLayoutOfTypar: denv:DisplayEnv -> x:Typar -> Layout
+
 val prettyStringOfTy: denv:DisplayEnv -> x:TType -> string
 
 val prettyStringOfTyNoCx: denv:DisplayEnv -> x:TType -> string

src/fsharp/service/FSharpCheckerResults.fs

@@ -1046,14 +1046,15 @@ type internal TypeCheckInfo
             | Some(CompletionContext.RecordField(RecordContext.Declaration false)) ->
                 GetDeclaredItems (parseResultsOpt, lineStr, origLongIdentOpt, colAtEndOfNamesAndResidue, residueOpt, lastDotPos, line, loc, filterCtors, resolveOverloads, false, getAllSymbols)
                 |> Option.map (fun (items, denv, m) ->
-                     items
-                     |> List.filter (fun cItem ->
-                         match cItem.Item with
-                         | Item.ModuleOrNamespaces _
-                         | Item.Types _
-                         | Item.UnqualifiedType _
-                         | Item.ExnCase _ -> true
-                         | _ -> false), denv, m)
+                    items
+                    |> List.filter (fun cItem ->
+                        match cItem.Item with
+                        | Item.ModuleOrNamespaces _
+                        | Item.Types _
+                        | Item.TypeVar _
+                        | Item.UnqualifiedType _
+                        | Item.ExnCase _ -> true
+                        | _ -> false), denv, m)
 
             // Other completions
             | cc ->

src/fsharp/service/ServiceConstants.fs

@@ -24,4 +24,5 @@ type FSharpGlyph =
     | Union
     | Variable
     | ExtensionMethod
-    | Error
\ No newline at end of file
+    | Error
+    | TypeParameter
\ No newline at end of file

src/fsharp/service/ServiceDeclarationLists.fs

@@ -380,6 +380,11 @@ module DeclarationListHelpers =
             let remarks = toArray remarks
             ToolTipElement.Single (layout, xml, remarks=remarks)
 
+        // Type variables
+        | Item.TypeVar (_, typar) ->
+            let layout = NicePrint.prettyLayoutOfTypar denv typar
+            ToolTipElement.Single (toArray layout, xml)
+
         // F# Modules and namespaces
         | Item.ModuleOrNamespaces(modref :: _ as modrefs) -> 
             //let os = StringBuilder()
@@ -848,7 +853,7 @@ module internal DescriptionListsImpl =
             | Item.CustomOperation _ -> FSharpGlyph.Method
             | Item.MethodGroup (_, minfos, _) when minfos |> List.forall (fun minfo -> minfo.IsExtensionMember) -> FSharpGlyph.ExtensionMethod
             | Item.MethodGroup _ -> FSharpGlyph.Method
-            | Item.TypeVar _ 
+            | Item.TypeVar _ -> FSharpGlyph.TypeParameter
             | Item.Types _  -> FSharpGlyph.Class
             | Item.UnqualifiedType (tcref :: _) -> 
                 if tcref.IsEnumTycon || tcref.IsILEnumTycon then FSharpGlyph.Enum
@@ -1031,9 +1036,12 @@ type DeclarationListInfo(declarations: DeclarationListItem[], isForType: bool, i
                     | Some u -> u.DisplayName
                     | None -> item.Item.DisplayNameCore
                 let textInCode = 
-                    match item.Unresolved with
-                    | Some u -> u.DisplayName
-                    | None -> item.Item.DisplayName
+                    match item.Item with
+                    | Item.TypeVar (name, typar) -> (if typar.StaticReq = Syntax.TyparStaticReq.None then "'" else " ^") + name
+                    | _ ->
+                        match item.Unresolved with
+                        | Some u -> u.DisplayName
+                        | None -> item.Item.DisplayName
                 textInDeclList, textInCode, items)
 
             // Filter out operators, active patterns (as values)

src/fsharp/service/ServiceParsedInputOps.fs

@@ -957,6 +957,9 @@ module ParsedInput =
                                 | _ -> 
                                     defaultTraverse expr
 
+                            // Unchecked.defaultof<str$>
+                            | SynExpr.TypeApp (typeArgsRange = range) when rangeContainsPos range pos ->
+                                Some CompletionContext.PatternType
                             | _ -> defaultTraverse expr
 
                     member _.VisitRecordField(path, copyOpt, field) = 

tests/FSharp.Compiler.Service.Tests/FSharp.CompilerService.SurfaceArea.netstandard.expected

@@ -2654,6 +2654,7 @@ FSharp.Compiler.EditorServices.FSharpGlyph+Tags: Int32 Property
 FSharp.Compiler.EditorServices.FSharpGlyph+Tags: Int32 Struct
 FSharp.Compiler.EditorServices.FSharpGlyph+Tags: Int32 Type
 FSharp.Compiler.EditorServices.FSharpGlyph+Tags: Int32 Typedef
+FSharp.Compiler.EditorServices.FSharpGlyph+Tags: Int32 TypeParameter
 FSharp.Compiler.EditorServices.FSharpGlyph+Tags: Int32 Union
 FSharp.Compiler.EditorServices.FSharpGlyph+Tags: Int32 Variable
 FSharp.Compiler.EditorServices.FSharpGlyph: Boolean Equals(FSharp.Compiler.EditorServices.FSharpGlyph)
@@ -2678,6 +2679,7 @@ FSharp.Compiler.EditorServices.FSharpGlyph: Boolean IsProperty
 FSharp.Compiler.EditorServices.FSharpGlyph: Boolean IsStruct
 FSharp.Compiler.EditorServices.FSharpGlyph: Boolean IsType
 FSharp.Compiler.EditorServices.FSharpGlyph: Boolean IsTypedef
+FSharp.Compiler.EditorServices.FSharpGlyph: Boolean IsTypeParameter
 FSharp.Compiler.EditorServices.FSharpGlyph: Boolean IsUnion
 FSharp.Compiler.EditorServices.FSharpGlyph: Boolean IsVariable
 FSharp.Compiler.EditorServices.FSharpGlyph: Boolean get_IsClass()
@@ -2699,6 +2701,7 @@ FSharp.Compiler.EditorServices.FSharpGlyph: Boolean get_IsProperty()
 FSharp.Compiler.EditorServices.FSharpGlyph: Boolean get_IsStruct()
 FSharp.Compiler.EditorServices.FSharpGlyph: Boolean get_IsType()
 FSharp.Compiler.EditorServices.FSharpGlyph: Boolean get_IsTypedef()
+FSharp.Compiler.EditorServices.FSharpGlyph: Boolean get_IsTypeParameter()
 FSharp.Compiler.EditorServices.FSharpGlyph: Boolean get_IsUnion()
 FSharp.Compiler.EditorServices.FSharpGlyph: Boolean get_IsVariable()
 FSharp.Compiler.EditorServices.FSharpGlyph: FSharp.Compiler.EditorServices.FSharpGlyph Class
@@ -2720,6 +2723,7 @@ FSharp.Compiler.EditorServices.FSharpGlyph: FSharp.Compiler.EditorServices.FShar
 FSharp.Compiler.EditorServices.FSharpGlyph: FSharp.Compiler.EditorServices.FSharpGlyph Struct
 FSharp.Compiler.EditorServices.FSharpGlyph: FSharp.Compiler.EditorServices.FSharpGlyph Type
 FSharp.Compiler.EditorServices.FSharpGlyph: FSharp.Compiler.EditorServices.FSharpGlyph Typedef
+FSharp.Compiler.EditorServices.FSharpGlyph: FSharp.Compiler.EditorServices.FSharpGlyph TypeParameter
 FSharp.Compiler.EditorServices.FSharpGlyph: FSharp.Compiler.EditorServices.FSharpGlyph Union
 FSharp.Compiler.EditorServices.FSharpGlyph: FSharp.Compiler.EditorServices.FSharpGlyph Variable
 FSharp.Compiler.EditorServices.FSharpGlyph: FSharp.Compiler.EditorServices.FSharpGlyph get_Class()
@@ -2741,6 +2745,7 @@ FSharp.Compiler.EditorServices.FSharpGlyph: FSharp.Compiler.EditorServices.FShar
 FSharp.Compiler.EditorServices.FSharpGlyph: FSharp.Compiler.EditorServices.FSharpGlyph get_Struct()
 FSharp.Compiler.EditorServices.FSharpGlyph: FSharp.Compiler.EditorServices.FSharpGlyph get_Type()
 FSharp.Compiler.EditorServices.FSharpGlyph: FSharp.Compiler.EditorServices.FSharpGlyph get_Typedef()
+FSharp.Compiler.EditorServices.FSharpGlyph: FSharp.Compiler.EditorServices.FSharpGlyph get_TypeParameter()
 FSharp.Compiler.EditorServices.FSharpGlyph: FSharp.Compiler.EditorServices.FSharpGlyph get_Union()
 FSharp.Compiler.EditorServices.FSharpGlyph: FSharp.Compiler.EditorServices.FSharpGlyph get_Variable()
 FSharp.Compiler.EditorServices.FSharpGlyph: FSharp.Compiler.EditorServices.FSharpGlyph+Tags

vsintegration/src/FSharp.Editor/Common/Extensions.fs

@@ -221,6 +221,7 @@ type NavigationItem with
             | Some SynAccess.Internal -> FSharpRoslynGlyph.ExtensionMethodInternal
             | _ -> FSharpRoslynGlyph.ExtensionMethodPublic
         | FSharpGlyph.Error -> FSharpRoslynGlyph.Error
+        | FSharpGlyph.TypeParameter -> FSharpRoslynGlyph.TypeParameter
 
 [<RequireQualifiedAccess>]
 module String =   

vsintegration/src/FSharp.Editor/LanguageService/Tokenizer.fs

@@ -147,6 +147,7 @@ module internal Tokenizer =
             | Private -> Glyph.StructurePrivate
         | FSharpGlyph.Variable -> Glyph.Local
         | FSharpGlyph.Error -> Glyph.Error
+        | FSharpGlyph.TypeParameter -> Glyph.TypeParameter
 
     let GetImageIdForSymbol(symbolOpt:FSharpSymbol option, kind:LexerSymbolKind) =
         let imageId =
@@ -243,6 +244,7 @@ module internal Tokenizer =
                         | Internal -> KnownImageIds.ClassInternal
                         | Protected -> KnownImageIds.ClassProtected
                         | Private -> KnownImageIds.ClassPrivate
+                | :? FSharpGenericParameter -> KnownImageIds.Type
                 | _ -> KnownImageIds.None
         if imageId = KnownImageIds.None then
             None
@@ -345,6 +347,7 @@ module internal Tokenizer =
                     | Internal -> Glyph.ClassInternal
                     | Protected -> Glyph.ClassProtected
                     | Private -> Glyph.ClassPrivate
+            | :? FSharpGenericParameter -> Glyph.TypeParameter
             | _ -> Glyph.None
 
 

vsintegration/src/FSharp.LanguageService/Intellisense.fs

@@ -219,6 +219,7 @@ type internal FSharpDeclarations_DEPRECATED(documentationBuilder, declarations:
             | FSharpGlyph.Field
             | FSharpGlyph.Delegate
             | FSharpGlyph.Variable
+            | FSharpGlyph.TypeParameter
             | FSharpGlyph.Error -> None
             |> Option.defaultValue ObsoleteGlyph.Class
             |> int

vsintegration/tests/UnitTests/CompletionProviderTests.fs

@@ -751,9 +751,9 @@ type A = { le: string }
     VerifyNoCompletionList(fileContents, "le")
 
 [<Test>]
-let ``Completion list on record field type at declaration site contains modules and types but not keywords or functions``() =
+let ``Completion list on record field type at declaration site contains modules, types and type parameters but not keywords or functions``() =
     let fileContents = """
-type A = { Field: l }
+type A<'lType> = { Field: l }
 """
     VerifyCompletionList(fileContents, "Field: l", ["LanguagePrimitives"; "List"], ["let"; "log"])
 
@@ -774,20 +774,28 @@ type A =
     VerifyNoCompletionList(fileContents, "str")
 
 [<Test>]
-let ``Completion list on union case type at declaration site contains modules and types but not keywords or functions``() =
+let ``Completion list on union case type at declaration site contains modules, types and type parameters but not keywords or functions``() =
     let fileContents = """
-type A =
+type A<'lType> =
     | Case of blah: int * str: l
 """
-    VerifyCompletionList(fileContents, "str: l", ["LanguagePrimitives"; "List"], ["let"; "log"])
+    VerifyCompletionList(fileContents, "str: l", ["LanguagePrimitives"; "List"; "lType"], ["let"; "log"])
 
 [<Test>]
-let ``Completion list on union case type at declaration site contains modules and types but not keywords or functions2``() =
+let ``Completion list on union case type at declaration site contains modules, types and type parameters but not keywords or functions2``() =
     let fileContents = """
-type A =
+type A<'lType> =
     | Case of l
 """
-    VerifyCompletionList(fileContents, "of l", ["LanguagePrimitives"; "List"], ["let"; "log"])
+    VerifyCompletionList(fileContents, "of l", ["LanguagePrimitives"; "List"; "lType"], ["let"; "log"])
+
+[<Test>]
+let ``Completion list on union case type at declaration site contains type parameter``() =
+    let fileContents = """
+type A<'keyType> =
+    | Case of key
+"""
+    VerifyCompletionList(fileContents, "of key", ["keyType"], [])
 
 [<Test>]
 let ``Completion list on type alias contains modules and types but not keywords or functions``() =
@@ -804,6 +812,38 @@ type A =
 """
     VerifyNoCompletionList(fileContents, "| C")
 
+[<Test>]
+let ``Completion list in generic function body contains type parameter``() =
+    let fileContents = """
+let Null<'wrappedType> () =
+    Unchecked.defaultof<wrapp>
+"""
+    VerifyCompletionList(fileContents, "defaultof<wrapp", ["wrappedType"], [])
+
+[<Test>]
+let ``Completion list in generic method body contains type parameter``() =
+    let fileContents = """
+type A () =
+    member _.Null<'wrappedType> () = Unchecked.defaultof<wrapp>
+"""
+    VerifyCompletionList(fileContents, "defaultof<wrapp", ["wrappedType"], [])
+
+[<Test>]
+let ``Completion list in generic class method body contains type parameter``() =
+    let fileContents = """
+type A<'wrappedType> () =
+    member _.Null () = Unchecked.defaultof<wrapp>
+"""
+    VerifyCompletionList(fileContents, "defaultof<wrapp", ["wrappedType"], [])
+
+[<Test>]
+let ``Completion list in type application contains modules, types and type parameters but not keywords or functions``() =
+    let fileContents = """
+let emptyMap<'keyType, 'lValueType> () =
+    Map.empty<'keyType, l>
+"""
+    VerifyCompletionList(fileContents, ", l", ["LanguagePrimitives"; "List"; "lValueType"], ["let"; "log"])
+
 #if EXE
 ShouldDisplaySystemNamespace()
 #endif