Keep parsed lambda patterns and expression in syntax tree (#10166)

src/fsharp/MethodCalls.fs

@@ -619,7 +619,7 @@ type ArgumentAnalysis =
 let InferLambdaArgsForLambdaPropagation origRhsExpr = 
     let rec loop e = 
         match e with 
-        | SynExpr.Lambda (_, _, _, rest, _) -> 1 + loop rest
+        | SynExpr.Lambda (_, _, _, rest, _, _) -> 1 + loop rest
         | SynExpr.MatchLambda _ -> 1
         | _ -> 0
     loop origRhsExpr

src/fsharp/SyntaxTree.fs

@@ -665,13 +665,16 @@ type SynExpr =
 
     /// First bool indicates if lambda originates from a method. Patterns here are always "simple"
     /// Second bool indicates if this is a "later" part of an iterated sequence of lambdas
+    /// parsedData keeps original parsed patterns and expression,
+    /// prior to transforming to "simple" patterns and iterated lambdas 
     ///
     /// F# syntax: fun pat -> expr
     | Lambda of
         fromMethod: bool *
         inLambdaSeq: bool *
         args: SynSimplePats *
         body: SynExpr *
+        parsedData: (SynPat list * SynExpr) option *
         range: range
 
     /// F# syntax: function pat1 -> expr | ... | patN -> exprN

src/fsharp/SyntaxTreeOps.fs

@@ -224,7 +224,7 @@ let rec SimplePatsOfPat synArgNameGenerator p =
 
 let PushPatternToExpr synArgNameGenerator isMember pat (rhs: SynExpr) =
     let nowPats, laterF = SimplePatsOfPat synArgNameGenerator pat
-    nowPats, SynExpr.Lambda (isMember, false, nowPats, appFunOpt laterF rhs, rhs.Range)
+    nowPats, SynExpr.Lambda (isMember, false, nowPats, appFunOpt laterF rhs, None, rhs.Range)
 
 let private isSimplePattern pat =
     let _nowPats, laterF = SimplePatsOfPat (SynArgNameGenerator()) pat
@@ -253,8 +253,8 @@ let PushCurriedPatternsToExpr synArgNameGenerator wholem isMember pats rhs =
         match spatsl with
         | [] -> rhs
         | h :: t ->
-            let expr = List.foldBack (fun spats e -> SynExpr.Lambda (isMember, true, spats, e, wholem)) t rhs
-            let expr = SynExpr.Lambda (isMember, false, h, expr, wholem)
+            let expr = List.foldBack (fun spats e -> SynExpr.Lambda (isMember, true, spats, e, None, wholem)) t rhs
+            let expr = SynExpr.Lambda (isMember, false, h, expr, Some (pats, rhs), wholem)
             expr
     spatsl, expr
 
@@ -330,7 +330,7 @@ let mkSynUnit m = SynExpr.Const (SynConst.Unit, m)
 let mkSynUnitPat m = SynPat.Const(SynConst.Unit, m)
 
 let mkSynDelay m e =
-    SynExpr.Lambda (false, false, SynSimplePats.SimplePats ([mkSynCompGenSimplePatVar (mkSynId m "unitVar")], m), e, m)
+    SynExpr.Lambda (false, false, SynSimplePats.SimplePats ([mkSynCompGenSimplePatVar (mkSynId m "unitVar")], m), e, None, m)
 
 let mkSynAssign (l: SynExpr) (r: SynExpr) =
     let m = unionRanges l.Range r.Range
@@ -498,7 +498,7 @@ module SynInfo =
     let InferLambdaArgs origRhsExpr =
         let rec loop e =
             match e with
-            | SynExpr.Lambda (false, _, spats, rest, _) ->
+            | SynExpr.Lambda (false, _, spats, rest, _, _) ->
                 InferSynArgInfoFromSimplePats spats :: loop rest
             | _ -> []
         loop origRhsExpr
@@ -692,7 +692,7 @@ let rec synExprContainsError inpExpr =
           | SynExpr.MatchLambda (_, _, cl, _, _) ->
               walkMatchClauses cl
 
-          | SynExpr.Lambda (_, _, _, e, _) ->
+          | SynExpr.Lambda (_, _, _, e, _, _) ->
               walkExpr e
 
           | SynExpr.Match (_, e, cl, _) ->

src/fsharp/TypeChecker.fs

@@ -2670,7 +2670,7 @@ module EventDeclarationNormalization =
 
                    match rhsExpr with 
                    // Detect 'fun () -> e' which results from the compilation of a property getter
-                   | SynExpr.Lambda (_, _, SynSimplePats.SimplePats([], _), trueRhsExpr, m) ->
+                   | SynExpr.Lambda (_, _, SynSimplePats.SimplePats([], _), trueRhsExpr, _, m) ->
                        let rhsExpr = mkSynApp1 (SynExpr.DotGet (SynExpr.Paren (trueRhsExpr, range0, None, m), range0, LongIdentWithDots([ident(target, m)], []), m)) (SynExpr.Ident (ident(argName, m))) m
 
                        // reconstitute rhsExpr
@@ -6414,7 +6414,7 @@ and TcExprUndelayed cenv overallTy env tpenv (synExpr: SynExpr) =
 /// Check lambdas as a group, to catch duplicate names in patterns
 and TcIteratedLambdas cenv isFirst (env: TcEnv) overallTy takenNames tpenv e = 
     match e with 
-    | SynExpr.Lambda (isMember, isSubsequent, spats, bodyExpr, m) when isMember || isFirst || isSubsequent ->
+    | SynExpr.Lambda (isMember, isSubsequent, spats, bodyExpr, _, m) when isMember || isFirst || isSubsequent ->
         let domainTy, resultTy = UnifyFunctionType None cenv env.DisplayEnv m overallTy
         let vs, (tpenv, names, takenNames) = TcSimplePats cenv isMember CheckCxs domainTy env (tpenv, Map.empty, takenNames) spats
         let envinner, _, vspecMap = MakeAndPublishSimpleValsForMergedScope cenv env m names 
@@ -8241,7 +8241,7 @@ and TcComputationExpression cenv env overallTy mWhole (interpExpr: Expr) builder
             Some (nm, Option.get (tryGetDataForCustomOperation nm), core, core.Range, optIntoInfo)
         | _ -> None
 
-    let mkSynLambda p e m = SynExpr.Lambda (false, false, p, e, m)
+    let mkSynLambda p e m = SynExpr.Lambda (false, false, p, e, None, m)
 
     let mkExprForVarSpace m (patvs: Val list) = 
         match patvs with 
@@ -8940,7 +8940,7 @@ and TcComputationExpression cenv env overallTy mWhole (interpExpr: Expr) builder
                                     // Check for the [<ProjectionParameter>] attribute on each argument position
                                     let args = args |> List.mapi (fun i arg -> 
                                         if isCustomOperationProjectionParameter (i+1) nm then 
-                                            SynExpr.Lambda (false, false, varSpaceSimplePat, arg, arg.Range.MakeSynthetic())
+                                            SynExpr.Lambda (false, false, varSpaceSimplePat, arg, None, arg.Range.MakeSynthetic())
                                         else arg)
                                     mkSynCall methInfo.DisplayName mClause (dataCompPrior :: args)
                                 else 
@@ -9180,7 +9180,7 @@ and TcComputationExpression cenv env overallTy mWhole (interpExpr: Expr) builder
 
     let lambdaExpr = 
         let mBuilderVal = mBuilderVal.MakeSynthetic()
-        SynExpr.Lambda (false, false, SynSimplePats.SimplePats ([mkSynSimplePatVar false (mkSynId mBuilderVal builderValName)], mBuilderVal), runExpr, mBuilderVal)
+        SynExpr.Lambda (false, false, SynSimplePats.SimplePats ([mkSynSimplePatVar false (mkSynId mBuilderVal builderValName)], mBuilderVal), runExpr, None, mBuilderVal)
 
     let env =
         match comp with
@@ -10574,7 +10574,7 @@ and GetNewInferenceTypeForMethodArg cenv env tpenv x =
     match x with 
     | SynExprParen(a, _, _, _) -> GetNewInferenceTypeForMethodArg cenv env tpenv a
     | SynExpr.AddressOf (true, a, _, m) -> mkByrefTyWithInference cenv.g (GetNewInferenceTypeForMethodArg cenv env tpenv a) (NewByRefKindInferenceType cenv.g m)
-    | SynExpr.Lambda (_, _, _, a, _) -> mkFunTy (NewInferenceType ()) (GetNewInferenceTypeForMethodArg cenv env tpenv a)
+    | SynExpr.Lambda (_, _, _, a, _, _) -> mkFunTy (NewInferenceType ()) (GetNewInferenceTypeForMethodArg cenv env tpenv a)
     | SynExpr.Quote (_, raw, a, _, _) -> 
         if raw then mkRawQuotedExprTy cenv.g
         else mkQuotedExprTy cenv.g (GetNewInferenceTypeForMethodArg cenv env tpenv a)

src/fsharp/service/ServiceAssemblyContent.fs

@@ -636,7 +636,7 @@ module ParsedInput =
             | SynExpr.Assert (e, _)
             | SynExpr.Lazy (e, _)
             | SynExpr.YieldOrReturnFrom (_, e, _) -> walkExpr e
-            | SynExpr.Lambda (_, _, pats, e, _) ->
+            | SynExpr.Lambda (_, _, pats, e, _, _) ->
                 walkSimplePats pats
                 walkExpr e
             | SynExpr.New (_, t, e, _)

src/fsharp/service/ServiceInterfaceStubGenerator.fs

@@ -802,7 +802,7 @@ module InterfaceStubGenerator =
                     walkExpr synExpr
                 | SynExpr.CompExpr (_, _, synExpr, _range) ->
                     walkExpr synExpr
-                | SynExpr.Lambda (_, _, _synSimplePats, synExpr, _range) ->
+                | SynExpr.Lambda (_, _, _synSimplePats, synExpr, _, _range) ->
                      walkExpr synExpr
 
                 | SynExpr.MatchLambda (_isExnMatch, _argm, synMatchClauseList, _spBind, _wholem) -> 

src/fsharp/service/ServiceParseTreeWalk.fs

@@ -391,7 +391,7 @@ module public AstTraversal =
                     else
                     traverseSynExpr synExpr
 
-                | SynExpr.Lambda (_, _, synSimplePats, synExpr, _range) ->
+                | SynExpr.Lambda (_, _, synSimplePats, synExpr, _, _range) ->
                     match synSimplePats with
                     | SynSimplePats.SimplePats(pats,_) ->
                         match visitor.VisitSimplePats(pats) with

src/fsharp/service/ServiceStructure.fs

@@ -376,7 +376,7 @@ module Structure =
             | SynExpr.While (_, _, e, r) ->
                 rcheck Scope.While Collapse.Below r r
                 parseExpr e
-            | SynExpr.Lambda (_, _, pats, e, r) ->
+            | SynExpr.Lambda (_, _, pats, e, _, r) ->
                 match pats with
                 | SynSimplePats.SimplePats (_, pr)
                 | SynSimplePats.Typed (_, _, pr) ->

src/fsharp/service/ServiceUntypedParse.fs

@@ -278,7 +278,7 @@ type FSharpParseFileResults(errors: FSharpErrorInfo[], input: ParsedInput option
                           yield! walkExprOpt false whenExpr
                           yield! walkExpr true e 
 
-                  | SynExpr.Lambda (_, _, _, e, _) -> 
+                  | SynExpr.Lambda (_, _, _, e, _, _) -> 
                       yield! walkExpr true e 
 
                   | SynExpr.Match (spBind, e, cl, _) ->
@@ -853,7 +853,7 @@ module UntypedParseImpl =
             | SynExpr.ForEach (_, _, _, _, e1, e2, _) -> List.tryPick (walkExprWithKind parentKind) [e1; e2]
             | SynExpr.ArrayOrListOfSeqExpr (_, e, _) -> walkExprWithKind parentKind e
             | SynExpr.CompExpr (_, _, e, _) -> walkExprWithKind parentKind e
-            | SynExpr.Lambda (_, _, _, e, _) -> walkExprWithKind parentKind e
+            | SynExpr.Lambda (_, _, _, e, _, _) -> walkExprWithKind parentKind e
             | SynExpr.MatchLambda (_, _, synMatchClauseList, _, _) -> 
                 List.tryPick walkClause synMatchClauseList
             | SynExpr.Match (_, e, synMatchClauseList, _) -> 

tests/FSharp.Compiler.Service.Tests/SurfaceArea.netstandard.fs

@@ -31673,6 +31673,8 @@ FSharp.Compiler.SyntaxTree+SynExpr+Lambda: SynExpr body
 FSharp.Compiler.SyntaxTree+SynExpr+Lambda: SynExpr get_body()
 FSharp.Compiler.SyntaxTree+SynExpr+Lambda: SynSimplePats args
 FSharp.Compiler.SyntaxTree+SynExpr+Lambda: SynSimplePats get_args()
+FSharp.Compiler.SyntaxTree+SynExpr+Lambda: Microsoft.FSharp.Core.FSharpOption`1[System.Tuple`2[Microsoft.FSharp.Collections.FSharpList`1[FSharp.Compiler.SyntaxTree+SynPat],FSharp.Compiler.SyntaxTree+SynExpr]] parsedData
+FSharp.Compiler.SyntaxTree+SynExpr+Lambda: Microsoft.FSharp.Core.FSharpOption`1[System.Tuple`2[Microsoft.FSharp.Collections.FSharpList`1[FSharp.Compiler.SyntaxTree+SynPat],FSharp.Compiler.SyntaxTree+SynExpr]] get_parsedData()
 FSharp.Compiler.SyntaxTree+SynExpr+Lambda: System.String ToString()
 FSharp.Compiler.SyntaxTree+SynExpr+Lambda: range Range
 FSharp.Compiler.SyntaxTree+SynExpr+Lambda: range RangeOfFirstPortion
@@ -36769,7 +36771,7 @@ FSharp.Compiler.SyntaxTree+SynExpr: SynExpr NewInferredDowncast(SynExpr, range)
 FSharp.Compiler.SyntaxTree+SynExpr: SynExpr NewInferredUpcast(SynExpr, range)
 FSharp.Compiler.SyntaxTree+SynExpr: SynExpr NewInterpolatedString(Microsoft.FSharp.Collections.FSharpList`1[FSharp.Compiler.SyntaxTree+SynInterpolatedStringPart], range)
 FSharp.Compiler.SyntaxTree+SynExpr: SynExpr NewJoinIn(SynExpr, range, SynExpr, range)
-FSharp.Compiler.SyntaxTree+SynExpr: SynExpr NewLambda(Boolean, Boolean, SynSimplePats, SynExpr, range)
+FSharp.Compiler.SyntaxTree+SynExpr: SynExpr NewLambda(Boolean, Boolean, SynSimplePats, SynExpr, Microsoft.FSharp.Core.FSharpOption`1[System.Tuple`2[Microsoft.FSharp.Collections.FSharpList`1[FSharp.Compiler.SyntaxTree+SynPat],FSharp.Compiler.SyntaxTree+SynExpr]], range)
 FSharp.Compiler.SyntaxTree+SynExpr: SynExpr NewLazy(SynExpr, range)
 FSharp.Compiler.SyntaxTree+SynExpr: SynExpr NewLetOrUse(Boolean, Boolean, Microsoft.FSharp.Collections.FSharpList`1[FSharp.Compiler.SyntaxTree+SynBinding], SynExpr, range)
 FSharp.Compiler.SyntaxTree+SynExpr: SynExpr NewLetOrUseBang(DebugPointForBinding, Boolean, Boolean, SynPat, SynExpr, Microsoft.FSharp.Collections.FSharpList`1[System.Tuple`6[FSharp.Compiler.SyntaxTree+DebugPointForBinding,System.Boolean,System.Boolean,FSharp.Compiler.SyntaxTree+SynPat,FSharp.Compiler.SyntaxTree+SynExpr,FSharp.Compiler.Range+range]], SynExpr, range)