Correct body SynExpr of parsedData of Lambda when wildcards are involved.

src/fsharp/SyntaxTreeOps.fs

@@ -174,10 +174,15 @@ let rec SimplePatOfPat (synArgNameGenerator: SynArgNameGenerator) p =
                 let id = mkSynId m nm
                 let item = mkSynIdGet m nm
                 true, None, id, item
-        SynSimplePat.Id (id, altNameRefCell, isCompGen, false, false, id.idRange),
-        Some (fun e ->
-                let clause = SynMatchClause(p, None, e, m, DebugPointForTarget.No)
-                SynExpr.Match (DebugPointAtBinding.NoneAtInvisible, item, [clause], clause.Range))
+        let fn =
+            match p with
+            | SynPat.Wild _ -> None
+            | _ ->
+                Some (fun e ->
+                    let clause = SynMatchClause(p, None, e, m, DebugPointForTarget.No)
+                    SynExpr.Match (DebugPointAtBinding.NoneAtInvisible, item, [clause], clause.Range))
+
+        SynSimplePat.Id (id, altNameRefCell, isCompGen, false, false, id.idRange), fn
 
 let appFunOpt funOpt x = match funOpt with None -> x | Some f -> f x
 

tests/service/Symbols.fs

@@ -1225,4 +1225,65 @@ module ParsedHashDirective =
         ]) ])) ->
             Assert.AreEqual("40", v)
             assertRange (1, 8) (1, 16) m
+        | _ -> Assert.Fail "Could not get valid AST"
+
+module Lambdas =
+    [<Test>]
+    let ``Lambda with two parameters gives correct body`` () =
+        let parseResults = 
+            getParseResults
+                "fun a b -> x"
+
+        match parseResults with
+        | ParsedInput.ImplFile (ParsedImplFileInput (modules = [ SynModuleOrNamespace.SynModuleOrNamespace(decls = [
+            SynModuleDecl.DoExpr(
+                expr = SynExpr.Lambda(parsedData = Some([SynPat.Named _; SynPat.Named _], SynExpr.Ident(ident)))
+            )
+        ]) ])) ->
+            Assert.AreEqual("x", ident.idText)
+        | _ -> Assert.Fail "Could not get valid AST"
+
+    [<Test>]
+    let ``Lambda with wild card parameter gives correct body`` () =
+        let parseResults = 
+            getParseResults
+                "fun a _ b -> x"
+
+        match parseResults with
+        | ParsedInput.ImplFile (ParsedImplFileInput (modules = [ SynModuleOrNamespace.SynModuleOrNamespace(decls = [
+            SynModuleDecl.DoExpr(
+                expr = SynExpr.Lambda(parsedData = Some([SynPat.Named _; SynPat.Wild _; SynPat.Named _], SynExpr.Ident(ident)))
+            )
+        ]) ])) ->
+            Assert.AreEqual("x", ident.idText)
+        | _ -> Assert.Fail "Could not get valid AST"
+
+    [<Test>]
+    let ``Lambda with tuple parameter with wild card gives correct body`` () =
+        let parseResults = 
+            getParseResults
+                "fun a (b, _) c -> x"
+
+        match parseResults with
+        | ParsedInput.ImplFile (ParsedImplFileInput (modules = [ SynModuleOrNamespace.SynModuleOrNamespace(decls = [
+            SynModuleDecl.DoExpr(
+                expr = SynExpr.Lambda(parsedData = Some([SynPat.Named _; SynPat.Paren(SynPat.Tuple _,_); SynPat.Named _], SynExpr.Ident(ident)))
+            )
+        ]) ])) ->
+            Assert.AreEqual("x", ident.idText)
+        | _ -> Assert.Fail "Could not get valid AST"
+
+    [<Test>]
+    let ``Lambda with wild card that returns a lambda gives correct body`` () =
+        let parseResults = 
+            getParseResults
+                "fun _ -> fun _ -> x"
+
+        match parseResults with
+        | ParsedInput.ImplFile (ParsedImplFileInput (modules = [ SynModuleOrNamespace.SynModuleOrNamespace(decls = [
+            SynModuleDecl.DoExpr(
+                expr = SynExpr.Lambda(parsedData = Some([SynPat.Wild _], SynExpr.Lambda(parsedData = Some([SynPat.Wild _], SynExpr.Ident(ident)))))
+            )
+        ]) ])) ->
+            Assert.AreEqual("x", ident.idText)
         | _ -> Assert.Fail "Could not get valid AST"