Shorthand lambda: fix completion for chained calls

docs/release-notes/.FSharp.Compiler.Service/10.0.100.md

@@ -1,3 +1,4 @@
 ### Fixed
 
 * Allow `let!` and `use!` type annotations without requiring parentheses ([PR #18508](https://github.com/dotnet/fsharp/pull/18508))
+* Shorthand lambda: fix completion for chained calls and analysis for unfinished expression ([PR #18560](https://github.com/dotnet/fsharp/pull/18560))

src/Compiler/Service/ServiceParsedInputOps.fs

@@ -320,6 +320,13 @@ module ParsedInput =
                             let _, r = CheckLongIdent longIdent
                             Some r
 
+                    | SynExpr.DotLambda(SynExpr.LongIdent _, range, _) -> Some range
+                    | SynExpr.DotLambda(synExpr, range, _) ->
+                        let result = traverseSynExpr synExpr
+
+                        result
+                        |> Option.map (fun r -> if posEq r.Start synExpr.Range.Start then range else r)
+
                     | SynExpr.DotGet(synExpr, _dotm, lid, _) ->
                         let (SynLongIdent(longIdent, _, _)) = lid
 

src/Compiler/SyntaxTree/SyntaxTreeOps.fs

@@ -103,6 +103,7 @@ let rec pushUnaryArg expr arg =
         SynExpr.TypeApp(innerExpr, mLess, tyargs, mCommas, mGreater, mTypars, m)
     | SynExpr.ArbitraryAfterError(_, m) when m.Start = m.End ->
         SynExpr.DiscardAfterMissingQualificationAfterDot(SynExpr.Ident arg, m.StartRange, unionRanges arg.idRange m)
+    | SynExpr.DiscardAfterMissingQualificationAfterDot(synExpr, _, _) -> pushUnaryArg synExpr arg
     | _ ->
         errorR (Error(FSComp.SR.tcDotLambdaAtNotSupportedExpression (), expr.Range))
         expr

tests/FSharp.Compiler.ComponentTests/Language/DotLambdaTests.fs

@@ -105,6 +105,17 @@ let myFunction (x:MyRecord) = x |> _.DoStuff 1 2 3"""
             Error 72, Line 4, Col 36, Line 4, Col 45, "Lookup on object of indeterminate type based on information prior to this program point. A type annotation may be needed prior to this program point to constrain the type of the object. This may allow the lookup to be resolved."
             ]
 
+[<Fact>]
+let ``Underscore Dot Lambda - Missing qualification after dot`` () =
+    Fsx """
+"" |> _.Length. """
+    |> withLangVersion80
+    |> typecheck
+    |> shouldFail
+    |> withDiagnostics [
+            Error 599, Line 2, Col 15, Line 2, Col 16, "Missing qualification after '.'"
+            ]
+
 [<Fact>]
 let ``Underscore Dot Length on string`` () =         
     Fsx """ 

tests/FSharp.Compiler.Service.Tests/CompletionTests.fs

@@ -78,29 +78,140 @@ let record = { Field = 1 }
     assertHasItemWithNames ["Field"; "record"] info
 
 [<Fact>]
-let ``Underscore dot lambda - completion`` () =
+let ``Underscore dot lambda - completion 01`` () =
     let info = getCompletionInfo """
-let myFancyFunc (x:string) = 
-    x 
-    |> _.Len{caret}"""
+"" |> _.Len{caret}"""
+
+    assertHasItemWithNames ["Length"] info
+
+[<Fact>]
+let ``Underscore dot lambda - completion 02`` () =
+    let info = getCompletionInfo """
+System.DateTime.Now |> _.TimeOfDay.Mill{caret}"""
+
+    assertHasItemWithNames ["Milliseconds"] info
+
+[<Fact>]
+let ``Underscore dot lambda - completion 03`` () =
+    let info = getCompletionInfo """
+"" |> _.ToString().Len{caret}"""
+
+    assertHasItemWithNames ["Length"] info
+
+[<Fact>]
+let ``Underscore dot lambda - completion 04`` () =
+    let info = getCompletionInfo """
+"" |> _.Len{caret}gth.ToString()"""
+
+    assertHasItemWithNames ["Length"] info
+
+[<Fact>]
+let ``Underscore dot lambda - completion 05`` () =
+    let info = getCompletionInfo """
+"" |> _.Length.ToString().Chars("".Len{caret})"""
+
     assertHasItemWithNames ["Length"] info
 
 [<Fact>]
-let ``Underscore dot lambda - method completion`` () =
+let ``Underscore dot lambda - completion 06`` () =
+    let info = getCompletionInfo """
+"" |> _.Chars(System.DateTime.UtcNow.Tic{caret}).ToString()"""
+
+    assertHasItemWithNames ["Ticks"] info
+
+[<Fact>]
+let ``Underscore dot lambda - completion 07`` () =
+    let info = getCompletionInfo """
+"" |> _.Length.ToString().Len{caret}"""
+
+    assertHasItemWithNames ["Length"] info
+
+[<Fact>]
+let ``Underscore dot lambda - completion 08`` () =
+    let info = getCompletionInfo """
+System.DateTime.Now |> _.TimeOfDay
+                        .Mill{caret}"""
+
+    assertHasItemWithNames ["Milliseconds"] info
+
+[<Fact>]
+let ``Underscore dot lambda - completion 09`` () =
+    let info = getCompletionInfo """
+"" |> _.Length.ToSt{caret}.Length"""
+
+    assertHasItemWithNames ["ToString"] info
+
+[<Fact>]
+let ``Underscore dot lambda - completion 10`` () =
+    let info = getCompletionInfo """
+"" |> _.Chars(0).ToStr{caret}.Length"""
+
+    assertHasItemWithNames ["ToString"] info
+
+[<Fact>]
+let ``Underscore dot lambda - completion 11`` () =
+    let info = getCompletionInfo """
+open System.Linq
+
+[[""]] |> _.Select(_.Head.ToL{caret})"""
+
+    assertHasItemWithNames ["ToLower"] info
+
+[<Fact>]
+let ``Underscore dot lambda - completion 12`` () =
+    let info = getCompletionInfo """
+open System.Linq
+
+[[[""]]] |> _.Head.Select(_.Head.ToL{caret})"""
+
+    assertHasItemWithNames ["ToLower"] info
+
+[<Fact>]
+let ``Underscore dot lambda - completion 13`` () =
     let info = getCompletionInfo """
-let myFancyFunc (x:string) = 
-    x 
+let myFancyFunc (x:string) =
+    x
     |> _.ToL{caret}"""
     assertHasItemWithNames ["ToLower"] info
 
 [<Fact>]
-let ``Underscore dot lambda - No prefix`` () =
+let ``Underscore dot lambda - completion 14`` () =
+    let info = getCompletionInfo """
+let myFancyFunc (x:System.DateTime) =
+    x
+    |> _.TimeOfDay.Mill{caret}
+    |> id"""
+    assertHasItemWithNames ["Milliseconds"] info
+
+[<Fact>]
+let ``Underscore dot lambda - completion 15`` () =
+    let info = getCompletionInfo """
+let _a = 5
+"" |> _{caret}.Length.ToString() """
+    assertHasItemWithNames ["_a"] info
+
+[<Fact>]
+let ``Underscore dot lambda - No prefix 01`` () =
     let info = getCompletionInfo """
 let s = ""
-[s] |> List.map _.{caret} 
+[s] |> List.map _.{caret}
 """
     assertHasItemWithNames ["Length"] info
 
+[<Fact>]
+let ``Underscore dot lambda - No prefix 02`` () =
+    let info = getCompletionInfo """
+System.DateTime.Now |> _.TimeOfDay.{caret}"""
+
+    assertHasItemWithNames ["Milliseconds"] info
+
+[<Fact>]
+let ``Underscore dot lambda - No prefix 03`` () =
+    let info = getCompletionInfo """
+"" |> _.Length.ToString().{caret}"""
+
+    assertHasItemWithNames ["Length"] info
+
 [<Fact>]
 let ``Type decl - Record - Field type 01`` () =
     let info = getCompletionInfo """

tests/ILVerify/ilverify_FSharp.Compiler.Service_Debug_netstandard2.0.bsl

@@ -34,7 +34,7 @@
 [IL]: Error [StackUnexpected]: : <StartupCode$FSharp-Compiler-Service>.$FSharpCheckerResults+dataTipOfReferences@2225::Invoke([FSharp.Core]Microsoft.FSharp.Core.Unit)][offset 0x00000084][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : FSharp.Compiler.EditorServices.AssemblyContent+traverseMemberFunctionAndValues@176::Invoke([FSharp.Compiler.Service]FSharp.Compiler.Symbols.FSharpMemberOrFunctionOrValue)][offset 0x00000059][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : FSharp.Compiler.EditorServices.AssemblyContent+traverseEntity@218::GenerateNext([S.P.CoreLib]System.Collections.Generic.IEnumerable`1<FSharp.Compiler.EditorServices.AssemblySymbol>&)][offset 0x000000DA][found Char] Unexpected type on the stack.
-[IL]: Error [StackUnexpected]: : FSharp.Compiler.EditorServices.ParsedInput+visitor@1424-6::VisitExpr([FSharp.Core]Microsoft.FSharp.Collections.FSharpList`1<FSharp.Compiler.Syntax.SyntaxNode>, [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<FSharp.Compiler.Syntax.SynExpr,Microsoft.FSharp.Core.FSharpOption`1<FSharp.Compiler.EditorServices.CompletionContext>>, [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<FSharp.Compiler.Syntax.SynExpr,Microsoft.FSharp.Core.FSharpOption`1<FSharp.Compiler.EditorServices.CompletionContext>>, [FSharp.Compiler.Service]FSharp.Compiler.Syntax.SynExpr)][offset 0x00000605][found Char] Unexpected type on the stack.
+[IL]: Error [StackUnexpected]: : FSharp.Compiler.EditorServices.ParsedInput+visitor@1431-6::VisitExpr([FSharp.Core]Microsoft.FSharp.Collections.FSharpList`1<FSharp.Compiler.Syntax.SyntaxNode>, [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<FSharp.Compiler.Syntax.SynExpr,Microsoft.FSharp.Core.FSharpOption`1<FSharp.Compiler.EditorServices.CompletionContext>>, [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<FSharp.Compiler.Syntax.SynExpr,Microsoft.FSharp.Core.FSharpOption`1<FSharp.Compiler.EditorServices.CompletionContext>>, [FSharp.Compiler.Service]FSharp.Compiler.Syntax.SynExpr)][offset 0x00000605][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : <StartupCode$FSharp-Compiler-Service>.$ServiceLexing+clo@922-509::Invoke([FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<System.Tuple`3<FSharp.Compiler.Parser+token,int32,int32>,Microsoft.FSharp.Core.Unit>)][offset 0x00000032][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : <StartupCode$FSharp-Compiler-Service>.$ServiceLexing+clo@922-509::Invoke([FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<System.Tuple`3<FSharp.Compiler.Parser+token,int32,int32>,Microsoft.FSharp.Core.Unit>)][offset 0x0000003B][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : <StartupCode$FSharp-Compiler-Service>.$ServiceLexing+clo@922-509::Invoke([FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<System.Tuple`3<FSharp.Compiler.Parser+token,int32,int32>,Microsoft.FSharp.Core.Unit>)][offset 0x00000082][found Char] Unexpected type on the stack.

tests/ILVerify/ilverify_FSharp.Compiler.Service_Release_netstandard2.0.bsl

@@ -33,7 +33,7 @@
 [IL]: Error [StackUnexpected]: : <StartupCode$FSharp-Compiler-Service>.$FSharpCheckerResults+GetReferenceResolutionStructuredToolTipText@2225::Invoke([FSharp.Core]Microsoft.FSharp.Core.Unit)][offset 0x00000076][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : FSharp.Compiler.EditorServices.AssemblyContent+traverseMemberFunctionAndValues@176::Invoke([FSharp.Compiler.Service]FSharp.Compiler.Symbols.FSharpMemberOrFunctionOrValue)][offset 0x0000002B][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : FSharp.Compiler.EditorServices.AssemblyContent+traverseEntity@218::GenerateNext([S.P.CoreLib]System.Collections.Generic.IEnumerable`1<FSharp.Compiler.EditorServices.AssemblySymbol>&)][offset 0x000000BB][found Char] Unexpected type on the stack.
-[IL]: Error [StackUnexpected]: : FSharp.Compiler.EditorServices.ParsedInput+visitor@1424-11::VisitExpr([FSharp.Core]Microsoft.FSharp.Collections.FSharpList`1<FSharp.Compiler.Syntax.SyntaxNode>, [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<FSharp.Compiler.Syntax.SynExpr,Microsoft.FSharp.Core.FSharpOption`1<FSharp.Compiler.EditorServices.CompletionContext>>, [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<FSharp.Compiler.Syntax.SynExpr,Microsoft.FSharp.Core.FSharpOption`1<FSharp.Compiler.EditorServices.CompletionContext>>, [FSharp.Compiler.Service]FSharp.Compiler.Syntax.SynExpr)][offset 0x00000620][found Char] Unexpected type on the stack.
+[IL]: Error [StackUnexpected]: : FSharp.Compiler.EditorServices.ParsedInput+visitor@1431-11::VisitExpr([FSharp.Core]Microsoft.FSharp.Collections.FSharpList`1<FSharp.Compiler.Syntax.SyntaxNode>, [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<FSharp.Compiler.Syntax.SynExpr,Microsoft.FSharp.Core.FSharpOption`1<FSharp.Compiler.EditorServices.CompletionContext>>, [FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<FSharp.Compiler.Syntax.SynExpr,Microsoft.FSharp.Core.FSharpOption`1<FSharp.Compiler.EditorServices.CompletionContext>>, [FSharp.Compiler.Service]FSharp.Compiler.Syntax.SynExpr)][offset 0x00000620][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : <StartupCode$FSharp-Compiler-Service>.$ServiceLexing+clo@922-530::Invoke([FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<System.Tuple`3<FSharp.Compiler.Parser+token,int32,int32>,Microsoft.FSharp.Core.Unit>)][offset 0x00000032][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : <StartupCode$FSharp-Compiler-Service>.$ServiceLexing+clo@922-530::Invoke([FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<System.Tuple`3<FSharp.Compiler.Parser+token,int32,int32>,Microsoft.FSharp.Core.Unit>)][offset 0x0000003B][found Char] Unexpected type on the stack.
 [IL]: Error [StackUnexpected]: : <StartupCode$FSharp-Compiler-Service>.$ServiceLexing+clo@922-530::Invoke([FSharp.Core]Microsoft.FSharp.Core.FSharpFunc`2<System.Tuple`3<FSharp.Compiler.Parser+token,int32,int32>,Microsoft.FSharp.Core.Unit>)][offset 0x00000064][found Char] Unexpected type on the stack.