[WIP and Blocked] Inline hints for F#

eng/Versions.props

@@ -97,7 +97,7 @@
     <SystemThreadingThreadPoolVersion>4.3.0</SystemThreadingThreadPoolVersion>
     <SystemValueTupleVersion>4.5.0</SystemValueTupleVersion>
     <!-- Roslyn packages -->
-    <RoslynVersion>3.9.0-1.20512.2</RoslynVersion>
+    <RoslynVersion>3.9.0-2.20516.5</RoslynVersion>
     <MicrosoftCodeAnalysisEditorFeaturesVersion>$(RoslynVersion)</MicrosoftCodeAnalysisEditorFeaturesVersion>
     <MicrosoftCodeAnalysisEditorFeaturesTextVersion>$(RoslynVersion)</MicrosoftCodeAnalysisEditorFeaturesTextVersion>
     <MicrosoftCodeAnalysisEditorFeaturesWpfVersion>$(RoslynVersion)</MicrosoftCodeAnalysisEditorFeaturesWpfVersion>

global.json

@@ -1,10 +1,9 @@
 {
   "sdk": {
-    "version": "3.1.302",
-    "rollForward": "minor"
+    "version": "3.1.403"
   },
   "tools": {
-    "dotnet": "3.1.302",
+    "dotnet": "3.1.403",
     "vs": {
       "version": "16.4",
       "components": [

src/fsharp/NicePrint.fs

@@ -1198,7 +1198,18 @@ module private PrintTypes =
 
     let prettyLayoutOfTypeNoConstraints denv ty = 
         let ty, _cxs = PrettyTypes.PrettifyType denv.g ty
-        layoutTypeWithInfoAndPrec denv SimplifyTypes.typeSimplificationInfo0 5 ty 
+        layoutTypeWithInfoAndPrec denv SimplifyTypes.typeSimplificationInfo0 5 ty
+
+    let layoutOfValReturnType denv (v: ValRef) =
+        match v.ValReprInfo with 
+        | None ->
+            let _, tau = v.TypeScheme
+            let _argtysl, rty = stripFunTy denv.g tau
+            layoutReturnType denv SimplifyTypes.typeSimplificationInfo0 rty
+        | Some (ValReprInfo(_typars, argInfos, _retInfo)) -> 
+            let tau = v.TauType
+            let _c, rty = GetTopTauTypeInFSharpForm denv.g argInfos tau Range.range0
+            layoutReturnType denv SimplifyTypes.typeSimplificationInfo0 rty
 
     let layoutAssemblyName _denv (ty: TType) =
         ty.GetAssemblyName()
@@ -2223,7 +2234,9 @@ let prettyLayoutOfValOrMember denv typarInst v = PrintTastMemberOrVals.prettyLay
 
 let prettyLayoutOfValOrMemberNoInst denv v = PrintTastMemberOrVals.prettyLayoutOfValOrMemberNoInst denv v
 
-let prettyLayoutOfMemberNoInstShort denv v = PrintTastMemberOrVals.prettyLayoutOfMemberNoInstShort denv v 
+let prettyLayoutOfMemberNoInstShort denv v = PrintTastMemberOrVals.prettyLayoutOfMemberNoInstShort denv v
+
+let layoutOfValReturnType denv x = x |> PrintTypes.layoutOfValReturnType denv
 
 let prettyLayoutOfInstAndSig denv x = PrintTypes.prettyLayoutOfInstAndSig denv x
 

src/fsharp/TypedTreeOps.fs

@@ -2844,7 +2844,7 @@ let tagEntityRefName (xref: EntityRef) name =
     elif xref.IsFSharpDelegateTycon then tagDelegate name
     elif xref.IsILEnumTycon || xref.IsFSharpEnumTycon then tagEnum name
     elif xref.IsStructOrEnumTycon then tagStruct name
-    elif xref.IsFSharpInterfaceTycon then tagInterface name
+    elif isInterfaceTyconRef xref then tagInterface name
     elif xref.IsUnionTycon then tagUnion name
     elif xref.IsRecordTycon then tagRecord name
     else tagClass name

src/fsharp/service/ServiceParamInfoLocations.fs

@@ -6,8 +6,19 @@ open FSharp.Compiler.SyntaxTree
 open FSharp.Compiler.SyntaxTreeOps
 open FSharp.Compiler.Range
 
+type TupledArgumentLocation = { IsNamedArgument: bool; ArgumentRange: range }
+
 [<Sealed>]
-type FSharpNoteworthyParamInfoLocations(longId: string list, longIdRange: range, openParenLocation: pos,  tupleEndLocations: pos list, isThereACloseParen: bool, namedParamNames: string option list) =
+type FSharpNoteworthyParamInfoLocations
+    (
+        longId: string list,
+        longIdRange: range,
+        openParenLocation: pos,
+        argRanges: TupledArgumentLocation list, 
+        tupleEndLocations: pos list,
+        isThereACloseParen: bool,
+        namedParamNames: string option list
+    ) =
 
     let tupleEndLocations = Array.ofList tupleEndLocations
     let namedParamNames = Array.ofList namedParamNames
@@ -28,6 +39,7 @@ type FSharpNoteworthyParamInfoLocations(longId: string list, longIdRange: range,
     member this.TupleEndLocations = tupleEndLocations
     member this.IsThereACloseParen = isThereACloseParen
     member this.NamedParamNames = namedParamNames
+    member this.ArgumentLocations = argRanges |> Array.ofList
 
 [<AutoOpen>]
 module internal NoteworthyParamInfoLocationsImpl =
@@ -50,7 +62,7 @@ module internal NoteworthyParamInfoLocationsImpl =
         | _ -> None
 
     type FindResult = 
-        | Found of openParen: pos * commasAndCloseParen: (pos * string option) list * hasClosedParen: bool
+        | Found of openParen: pos * argRanges: TupledArgumentLocation list * commasAndCloseParen: (pos * string option) list * hasClosedParen: bool
         | NotFound
 
     let digOutIdentFromStaticArg (StripParenTypes synType) =
@@ -86,7 +98,8 @@ module internal NoteworthyParamInfoLocationsImpl =
         match inner with
         | None ->
             if AstTraversal.rangeContainsPosLeftEdgeExclusiveAndRightEdgeInclusive parenRange pos then
-                Found (parenRange.Start, [(parenRange.End, getNamedParamName synExpr)], rpRangeOpt.IsSome), None
+                let argRanges = [{ IsNamedArgument = (getNamedParamName synExpr).IsSome; ArgumentRange = synExpr.Range }]
+                Found (parenRange.Start, argRanges, [(parenRange.End, getNamedParamName synExpr)], rpRangeOpt.IsSome), None
             else
                 NotFound, None
         | _ -> NotFound, None
@@ -103,8 +116,12 @@ module internal NoteworthyParamInfoLocationsImpl =
             match inner with
             | None ->
                 if AstTraversal.rangeContainsPosLeftEdgeExclusiveAndRightEdgeInclusive parenRange pos then
+                    // argRange, isNamed
+                    let argRanges =
+                        synExprList
+                        |> List.map (fun e -> { IsNamedArgument = (getNamedParamName e).IsSome; ArgumentRange = e.Range })
                     let commasAndCloseParen = ((synExprList, commaRanges@[parenRange]) ||> List.map2 (fun e c -> c.End, getNamedParamName e))
-                    let r = Found (parenRange.Start, commasAndCloseParen, rpRangeOpt.IsSome)
+                    let r = Found (parenRange.Start, argRanges, commasAndCloseParen, rpRangeOpt.IsSome)
                     r, None
                 else
                     NotFound, None
@@ -123,14 +140,14 @@ module internal NoteworthyParamInfoLocationsImpl =
 
         | SynExpr.ArbitraryAfterError (_debugStr, range) -> // single argument when e.g. after open paren you hit EOF
             if AstTraversal.rangeContainsPosEdgesExclusive range pos then
-                let r = Found (range.Start, [(range.End, None)], false)
+                let r = Found (range.Start, [], [(range.End, None)], false)
                 r, None
             else
                 NotFound, None
 
         | SynExpr.Const (SynConst.Unit, unitRange) ->
             if AstTraversal.rangeContainsPosEdgesExclusive unitRange pos then
-                let r = Found (unitRange.Start, [(unitRange.End, None)], true)
+                let r = Found (unitRange.Start, [], [(unitRange.End, None)], true)
                 r, None
             else
                 NotFound, None
@@ -141,7 +158,7 @@ module internal NoteworthyParamInfoLocationsImpl =
             | None ->
                 if AstTraversal.rangeContainsPosEdgesExclusive e.Range pos then
                     // any other expression doesn't start with parens, so if it was the target of an App, then it must be a single argument e.g. "f x"
-                    Found (e.Range.Start, [ (e.Range.End, None) ], false), Some inner
+                    Found (e.Range.Start, [], [ (e.Range.End, None) ], false), Some inner
                 else
                     NotFound, Some inner
             | _ -> NotFound, Some inner
@@ -153,7 +170,7 @@ module internal NoteworthyParamInfoLocationsImpl =
             let betweenTheBrackets = mkRange wholem.FileName openm.Start wholem.End
             if AstTraversal.rangeContainsPosEdgesExclusive betweenTheBrackets pos && args |> List.forall isStaticArg then
                 let commasAndCloseParen = [ for c in commas -> c.End ] @ [ wholem.End ]
-                Some (FSharpNoteworthyParamInfoLocations(pathOfLid lid, lidm, openm.Start, commasAndCloseParen, closemOpt.IsSome, args |> List.map digOutIdentFromStaticArg))
+                Some (FSharpNoteworthyParamInfoLocations(pathOfLid lid, lidm, openm.Start, [], commasAndCloseParen, closemOpt.IsSome, args |> List.map digOutIdentFromStaticArg))
             else
                 None
         | _ ->
@@ -169,9 +186,9 @@ module internal NoteworthyParamInfoLocationsImpl =
             | SynExpr.New (_, synType, synExpr, _) -> 
                 let constrArgsResult, cacheOpt = searchSynArgExpr traverseSynExpr pos synExpr
                 match constrArgsResult, cacheOpt with
-                | Found(parenLoc, args, isThereACloseParen), _ ->
+                | Found(parenLoc, argRanges, commasAndCloseParen, isThereACloseParen), _ ->
                     let typeName = getTypeName synType
-                    Some (FSharpNoteworthyParamInfoLocations(typeName, synType.Range, parenLoc, args |> List.map fst, isThereACloseParen, args |> List.map snd))
+                    Some (FSharpNoteworthyParamInfoLocations(typeName, synType.Range, parenLoc, argRanges, commasAndCloseParen |> List.map fst, isThereACloseParen, commasAndCloseParen |> List.map snd))
                 | NotFound, Some cache ->
                     cache
                 | _ ->
@@ -190,7 +207,7 @@ module internal NoteworthyParamInfoLocationsImpl =
                     if AstTraversal.rangeContainsPosEdgesExclusive typeArgsm pos then
                         // We found it, dig out ident
                         match digOutIdentFromFuncExpr synExpr with
-                        | Some(lid, lidRange) -> Some (FSharpNoteworthyParamInfoLocations(lid, lidRange, op.idRange.Start, [ wholem.End ], false, []))
+                        | Some(lid, lidRange) -> Some (FSharpNoteworthyParamInfoLocations(lid, lidRange, op.idRange.Start, [], [ wholem.End ], false, []))
                         | None -> None
                     else
                         None
@@ -205,7 +222,7 @@ module internal NoteworthyParamInfoLocationsImpl =
                     // Search the argument
                     let xResult, cacheOpt = searchSynArgExpr traverseSynExpr pos synExpr2
                     match xResult, cacheOpt with
-                    | Found(parenLoc, args, isThereACloseParen), _ ->
+                    | Found(parenLoc, argRanges, commasAndCloseParen, isThereACloseParen), _ ->
                         // We found it, dig out ident
                         match digOutIdentFromFuncExpr synExpr with
                         | Some(lid, lidRange) -> 
@@ -215,7 +232,7 @@ module internal NoteworthyParamInfoLocationsImpl =
                                 // For now, we don't support infix operators.
                                 None
                             else
-                                Some (FSharpNoteworthyParamInfoLocations(lid, lidRange, parenLoc, args |> List.map fst, isThereACloseParen, args |> List.map snd))
+                                Some (FSharpNoteworthyParamInfoLocations(lid, lidRange, parenLoc, argRanges, commasAndCloseParen |> List.map fst, isThereACloseParen, commasAndCloseParen |> List.map snd))
                         | None -> None
                     | NotFound, Some cache -> cache
                     | _ -> traverseSynExpr synExpr2
@@ -228,7 +245,8 @@ module internal NoteworthyParamInfoLocationsImpl =
                     let typeArgsm = mkRange openm.FileName openm.Start wholem.End 
                     if AstTraversal.rangeContainsPosEdgesExclusive typeArgsm pos && tyArgs |> List.forall isStaticArg then
                         let commasAndCloseParen = [ for c in commas -> c.End ] @ [ wholem.End ]
-                        let r = FSharpNoteworthyParamInfoLocations(["dummy"], synExpr.Range, openm.Start, commasAndCloseParen, closemOpt.IsSome, tyArgs |> List.map digOutIdentFromStaticArg)
+                        let argRanges = tyArgs |> List.map (fun tyarg -> { IsNamedArgument = false; ArgumentRange = tyarg.Range })
+                        let r = FSharpNoteworthyParamInfoLocations(["dummy"], synExpr.Range, openm.Start, argRanges, commasAndCloseParen, closemOpt.IsSome, tyArgs |> List.map digOutIdentFromStaticArg)
                         Some r
                     else
                         None
@@ -249,10 +267,10 @@ module internal NoteworthyParamInfoLocationsImpl =
                     // inherit ty(expr)    ---   treat it like an application (constructor call)
                     let xResult, _cacheOpt = searchSynArgExpr defaultTraverse pos expr
                     match xResult with
-                    | Found(parenLoc, args, isThereACloseParen) ->
+                    | Found(parenLoc, argRanges, commasAndCloseParen, isThereACloseParen) ->
                         // we found it, dig out ident
                         let typeName = getTypeName ty
-                        let r = FSharpNoteworthyParamInfoLocations(typeName, ty.Range, parenLoc, args |> List.map fst, isThereACloseParen, args |> List.map snd)
+                        let r = FSharpNoteworthyParamInfoLocations(typeName, ty.Range, parenLoc, argRanges, commasAndCloseParen |> List.map fst, isThereACloseParen, commasAndCloseParen |> List.map snd)
                         Some r
                     | NotFound -> None
                 else None
@@ -272,3 +290,58 @@ type FSharpNoteworthyParamInfoLocations with
             r
         | _ -> None
 
+module internal SynExprAppLocationsImpl =
+    let rec private searchSynArgExpr traverseSynExpr expr ranges =
+        match expr with
+        | SynExpr.Const(SynConst.Unit, _) ->
+            None, None
+
+        | SynExprParen(SynExpr.Tuple (_, exprs, _commas, _tupRange), _, _, _parenRange) ->
+            let rec loop (exprs: SynExpr list) ranges =
+                match exprs with
+                | [] -> ranges
+                | h::t ->
+                    loop t (h.Range :: ranges)
+
+            let res = loop exprs ranges
+            Some (res), None
+
+        | SynExprParen(SynExprParen(_, _, _, _) as synExpr, _, _, _parenRange) -> 
+            let r, _cacheOpt = searchSynArgExpr traverseSynExpr synExpr ranges
+            r, None
+
+        | SynExprParen(SynExpr.App (_, _isInfix, _, _, _range), _, _, parenRange) ->
+            Some (parenRange :: ranges), None
+
+        | e -> 
+            let inner = traverseSynExpr e
+            match inner with
+            | None ->
+                Some (e.Range :: ranges), Some inner
+            | _ -> None, Some inner
+
+    let getAllCurriedArgsAtPosition pos parseTree =
+        AstTraversal.Traverse(pos, parseTree, { new AstTraversal.AstVisitorBase<_>() with
+            member _.VisitExpr(_path, traverseSynExpr, defaultTraverse, expr) =
+                match expr with
+                | SynExpr.App (_exprAtomicFlag, _isInfix, funcExpr, argExpr, range) when posEq pos range.Start ->
+                    let isInfixFuncExpr =
+                        match funcExpr with
+                        | SynExpr.App (_, isInfix, _, _, _) -> isInfix
+                        | _ -> false
+
+                    if isInfixFuncExpr then
+                        traverseSynExpr funcExpr
+                    else
+                        let workingRanges =
+                            match traverseSynExpr funcExpr with
+                            | Some ranges -> ranges
+                            | None -> []
+
+                        let xResult, cacheOpt = searchSynArgExpr traverseSynExpr argExpr workingRanges
+                        match xResult, cacheOpt with
+                        | Some ranges, _ -> Some ranges
+                        | None, Some cache -> cache
+                        | _ -> traverseSynExpr argExpr
+                | _ -> defaultTraverse expr })
+        |> Option.map List.rev

src/fsharp/service/ServiceParamInfoLocations.fsi

@@ -10,6 +10,9 @@ namespace FSharp.Compiler.SourceCodeServices
 open FSharp.Compiler.Range
 open FSharp.Compiler.SyntaxTree
 
+/// Represents the location of a tupled argument, which can optionally be a named argument.
+type TupledArgumentLocation = { IsNamedArgument: bool; ArgumentRange: range }
+
 /// Represents the locations relevant to activating parameter info in an IDE
 [<Sealed>]
 type public FSharpNoteworthyParamInfoLocations =
@@ -33,8 +36,13 @@ type public FSharpNoteworthyParamInfoLocations =
     member IsThereACloseParen : bool   
 
     /// Either empty or a name if an actual named parameter; f(0,a=4,?b=None) would be [|None; Some "a"; Some "b"|]
-    member NamedParamNames : string option []  
+    member NamedParamNames : string option []
+
+    /// Array of locations for each argument, and a flag if that argument is named
+    member ArgumentLocations: TupledArgumentLocation []
 
     /// Find the information about parameter info locations at a particular source location
     static member Find : pos * ParsedInput -> FSharpNoteworthyParamInfoLocations option
 
+module internal SynExprAppLocationsImpl =
+    val getAllCurriedArgsAtPosition: pos: pos -> parseTree: ParsedInput -> range list option

src/fsharp/service/ServiceUntypedParse.fs

@@ -104,6 +104,61 @@ type FSharpParseFileResults(errors: FSharpErrorInfo[], input: ParsedInput option
         match input with
         | Some input -> FSharpNoteworthyParamInfoLocations.Find(pos, input)
         | _ -> None
+
+    member scope.GetAllArgumentsForFunctionApplicationAtPostion pos =
+        match input with
+        | Some input -> SynExprAppLocationsImpl.getAllCurriedArgsAtPosition pos input
+        | None -> None
+
+    member scope.IsTypeAnnotationGivenAtPosition pos =
+        match input with
+        | Some parseTree ->
+            let res =
+                AstTraversal.Traverse(pos, parseTree, { new AstTraversal.AstVisitorBase<_>() with
+                    member _.VisitExpr(_path, _traverseSynExpr, defaultTraverse, expr) =
+                        match expr with
+                        | SynExpr.Typed (_expr, _typeExpr, range) when posEq range.Start pos ->
+                            Some range
+                        | _ -> defaultTraverse expr
+
+                    override _.VisitSimplePats(pats) =
+                        match pats with
+                        | [] -> None
+                        | _ ->
+                            let exprFunc pat =
+                                match pat with
+                                | SynSimplePat.Typed (_pat, _targetExpr, range) when posEq range.Start pos ->
+                                    Some range
+                                | _ ->
+                                    None
+
+                            pats |> List.tryPick exprFunc
+
+                    override _.VisitPat(defaultTraverse, pat) =
+                        match pat with
+                        | SynPat.Typed (_pat, _targetType, range) when posEq range.Start pos ->
+                            Some range
+                        | _ -> defaultTraverse pat })
+            res.IsSome
+        | None -> false
+
+    member scope.IsBindingALambdaAtPosition pos =
+        match input with
+        | Some parseTree ->
+            let res =
+                AstTraversal.Traverse(pos, parseTree, { new AstTraversal.AstVisitorBase<_>() with
+                    member _.VisitExpr(_path, _traverseSynExpr, defaultTraverse, expr) =
+                        defaultTraverse expr
+
+                    override _.VisitBinding(defaultTraverse, binding) =
+                        match binding with
+                        | SynBinding.Binding(_, _, _, _, _, _, _, _, _, expr, range, _) when posEq range.Start pos ->
+                            match expr with
+                            | SynExpr.Lambda _ -> Some range
+                            | _ -> None
+                        | _ -> defaultTraverse binding })
+            res.IsSome
+        | None -> false
 
     /// Get declared items and the selected item at the specified location
     member private scope.GetNavigationItemsImpl() =