Only show type hints for lambdas + tests + surface

dotnet · Oct 28, 2020 · de05f68 · de05f68
1 parent 6f616fe
commit de05f68
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Showing 5 changed files with 79 additions and 6 deletions.
diff --git a/src/fsharp/service/ServiceUntypedParse.fs b/src/fsharp/service/ServiceUntypedParse.fs
@@ -140,8 +140,25 @@ type FSharpParseFileResults(errors: FSharpErrorInfo[], input: ParsedInput option
                             Some range
                         | _ -> defaultTraverse pat })
             res.IsSome
-        | None ->
-            false
+        | None -> false
+
+    member scope.IsBindingALambda(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() =

diff --git a/src/fsharp/service/ServiceUntypedParse.fsi b/src/fsharp/service/ServiceUntypedParse.fsi
@@ -25,9 +25,12 @@ type public FSharpParseFileResults =
     // doot doot yeet yeet
     member GetAllArgumentsForFunctionApplication: pos: pos -> range list option
 
-    // doot doot yeet yeet
+    // Determines if the expression or pattern at the given position has a type annotation
     member IsTypeAnnotationGiven: pos -> bool
 
+    // Determines if the binding at a given position is a lambda expression
+    member IsBindingALambda: pos -> bool
+
     /// Name of the file for which this information were created
     member FileName: string
 

diff --git a/tests/FSharp.Compiler.Service.Tests/SurfaceArea.netstandard.fs b/tests/FSharp.Compiler.Service.Tests/SurfaceArea.netstandard.fs
@@ -22427,6 +22427,7 @@ FSharp.Compiler.SourceCodeServices.FSharpMemberOrFunctionOrValue: Boolean IsOver
 FSharp.Compiler.SourceCodeServices.FSharpMemberOrFunctionOrValue: Boolean IsProperty
 FSharp.Compiler.SourceCodeServices.FSharpMemberOrFunctionOrValue: Boolean IsPropertyGetterMethod
 FSharp.Compiler.SourceCodeServices.FSharpMemberOrFunctionOrValue: Boolean IsPropertySetterMethod
+FSharp.Compiler.SourceCodeServices.FSharpMemberOrFunctionOrValue: Boolean IsMethod
 FSharp.Compiler.SourceCodeServices.FSharpMemberOrFunctionOrValue: Boolean IsSetterMethod
 FSharp.Compiler.SourceCodeServices.FSharpMemberOrFunctionOrValue: Boolean IsTypeFunction
 FSharp.Compiler.SourceCodeServices.FSharpMemberOrFunctionOrValue: Boolean IsUnresolved
@@ -22461,6 +22462,7 @@ FSharp.Compiler.SourceCodeServices.FSharpMemberOrFunctionOrValue: Boolean get_Is
 FSharp.Compiler.SourceCodeServices.FSharpMemberOrFunctionOrValue: Boolean get_IsProperty()
 FSharp.Compiler.SourceCodeServices.FSharpMemberOrFunctionOrValue: Boolean get_IsPropertyGetterMethod()
 FSharp.Compiler.SourceCodeServices.FSharpMemberOrFunctionOrValue: Boolean get_IsPropertySetterMethod()
+FSharp.Compiler.SourceCodeServices.FSharpMemberOrFunctionOrValue: Boolean get_IsMethod()
 FSharp.Compiler.SourceCodeServices.FSharpMemberOrFunctionOrValue: Boolean get_IsSetterMethod()
 FSharp.Compiler.SourceCodeServices.FSharpMemberOrFunctionOrValue: Boolean get_IsTypeFunction()
 FSharp.Compiler.SourceCodeServices.FSharpMemberOrFunctionOrValue: Boolean get_IsUnresolved()
@@ -22515,8 +22517,8 @@ FSharp.Compiler.SourceCodeServices.FSharpMemberOrFunctionOrValue: System.Collect
 FSharp.Compiler.SourceCodeServices.FSharpMemberOrFunctionOrValue: System.Collections.Generic.IList`1[FSharp.Compiler.SourceCodeServices.FSharpGenericParameter] get_GenericParameters()
 FSharp.Compiler.SourceCodeServices.FSharpMemberOrFunctionOrValue: System.Collections.Generic.IList`1[System.Collections.Generic.IList`1[FSharp.Compiler.SourceCodeServices.FSharpParameter]] CurriedParameterGroups
 FSharp.Compiler.SourceCodeServices.FSharpMemberOrFunctionOrValue: System.Collections.Generic.IList`1[System.Collections.Generic.IList`1[FSharp.Compiler.SourceCodeServices.FSharpParameter]] get_CurriedParameterGroups()
-FSharp.Compiler.SourceCodeServices.FSharpMemberOrFunctionOrValue: Microsoft.FSharp.Core.FSharpOption`1[Microsoft.FSharp.Collections.FSharpList1[System.String]] PossibleArgumentList
-FSharp.Compiler.SourceCodeServices.FSharpMemberOrFunctionOrValue: Microsoft.FSharp.Core.FSharpOption`1[Microsoft.FSharp.Collections.FSharpList1[System.String]] get_PossibleArgumentList()
+FSharp.Compiler.SourceCodeServices.FSharpMemberOrFunctionOrValue: Microsoft.FSharp.Core.FSharpOption`1[Microsoft.FSharp.Collections.FSharpList`1[System.String]] PossibleArgumentList
+FSharp.Compiler.SourceCodeServices.FSharpMemberOrFunctionOrValue: Microsoft.FSharp.Core.FSharpOption`1[Microsoft.FSharp.Collections.FSharpList`1[System.String]] get_PossibleArgumentList()
 FSharp.Compiler.SourceCodeServices.FSharpMemberOrFunctionOrValue: System.Collections.Generic.IList`1[System.String] ElaboratedXmlDoc
 FSharp.Compiler.SourceCodeServices.FSharpMemberOrFunctionOrValue: System.Collections.Generic.IList`1[System.String] XmlDoc
 FSharp.Compiler.SourceCodeServices.FSharpMemberOrFunctionOrValue: System.Collections.Generic.IList`1[System.String] get_ElaboratedXmlDoc()

diff --git a/tests/service/ServiceUntypedParseTests.fs b/tests/service/ServiceUntypedParseTests.fs
@@ -595,6 +595,15 @@ let f (x: int) (y: string) = ()
         Assert.IsTrue(parseFileResults.IsTypeAnnotationGiven (mkPos 2 7), "Expected annotation for argument 'x'")
         Assert.IsTrue(parseFileResults.IsTypeAnnotationGiven (mkPos 2 16), "Expected annotation for argument 'y'")
 
+    [<Test>]
+    let ``IsTypeAnnotationGiven - lambda function - all args annotated``() =
+        let source = """
+let f = fun (x: int) (y: string) -> ()
+"""
+        let parseFileResults, _ = getParseAndCheckResults source
+        Assert.IsTrue(parseFileResults.IsTypeAnnotationGiven (mkPos 2 13), "Expected a annotation for argument 'x'")
+        Assert.IsTrue(parseFileResults.IsTypeAnnotationGiven (mkPos 2 22), "Expected a annotation for argument 'y'")
+
     [<Test>]
     let ``IsTypeAnnotationGiven - constuctor - arg no annotations``() =
         let source = """
@@ -745,3 +754,41 @@ let (x, y: string) = (12, "hello")
         let parseFileResults, _ = getParseAndCheckResults source
         Assert.IsFalse(parseFileResults.IsTypeAnnotationGiven (mkPos 2 5), "Expected no annotation for argument 'x'")
         Assert.IsTrue(parseFileResults.IsTypeAnnotationGiven (mkPos 2 8), "Expected annotation for argument 'y'")
+
+module LambdaRecognition =
+    [<Test>]
+    let ``IsBindingALambda - recognize a lambda``() =
+        let source = """
+let f = fun x y -> x + y
+    """
+        let parseFileResults, _ = getParseAndCheckResults source
+        Assert.IsTrue(parseFileResults.IsBindingALambda (mkPos 2 4), "Expected 'f' to be a lambda expression")
+
+    [<Test>]
+    let ``IsBindingALambda - recognize a nested lambda``() =
+        let source = """
+let f =
+    fun x ->
+        fun y ->
+            x + y
+    """
+        let parseFileResults, _ = getParseAndCheckResults source
+        Assert.IsTrue(parseFileResults.IsBindingALambda (mkPos 2 4), "Expected 'f' to be a lambda expression")
+
+    [<Test>]
+    let ``IsBindingALambda - recognize a "partial" lambda``() =
+        let source = """
+let f x =
+    fun y ->
+        x + y
+    """
+        let parseFileResults, _ = getParseAndCheckResults source
+        Assert.IsTrue(parseFileResults.IsBindingALambda (mkPos 2 4), "Expected 'f' to be a lambda expression")
+
+    [<Test>]
+    let ``IsBindingALambda - not a lambda``() =
+        let source = """
+let f x y = x + y
+    """
+        let parseFileResults, _ = getParseAndCheckResults source
+        Assert.IsFalse(parseFileResults.IsBindingALambda (mkPos 2 4), "'f' is not a lambda expression'")
diff --git a/vsintegration/src/FSharp.Editor/InlineHints/InlineHints.fs b/vsintegration/src/FSharp.Editor/InlineHints/InlineHints.fs
@@ -37,9 +37,13 @@ type internal FSharpInlineHintsService
                 let parameterHints = ImmutableArray.CreateBuilder()
 
                 let isValidForTypeHint (funcOrValue: FSharpMemberOrFunctionOrValue) (symbolUse: FSharpSymbolUse) =
+                    let isLambdaIfFunction =
+                        funcOrValue.IsFunction &&
+                        parseFileResults.IsBindingALambda symbolUse.RangeAlternate.Start
+
+                    (funcOrValue.IsValue || isLambdaIfFunction) &&
                     not (parseFileResults.IsTypeAnnotationGiven symbolUse.RangeAlternate.Start) &&
                     symbolUse.IsFromDefinition &&
-                    (funcOrValue.IsValue || funcOrValue.IsFunction) &&
                     not funcOrValue.IsMember &&
                     not funcOrValue.IsMemberThisValue &&
                     not funcOrValue.IsConstructorThisValue &&