Add regression test: #13114, SynPat.Record and QuoteExpr traversal (#19468)

* Add regression test for #9382: SRTP stress test with matrix inverse

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Add regression test for #13114: SynPat.Record and QuoteExpr traversal

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Fix regression tests for #13114: remove unrelated test, add IsInst and FromParseError

- Remove the SRTP matrix inverse test from MemberConstraints.fs: it references
  issue #9382 and is unrelated to this PR (#13114).
- Add SynPat.IsInst test: verifies defaultTraverse descends into the SynType
  inside :? type-test patterns.
- Add SynPat.FromParseError test: verifies defaultTraverse descends into the
  nested pattern wrapped by FromParseError.

Per reviewer feedback from @abonie.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Remove extra trailing newline in TreeVisitorTests (retrigger CI)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Remove SynPat.IsInst test: defaultTraverse does not handle IsInst (bug still present)

SynPat.IsInst is not in the traversePat defaultTraverse in ServiceParseTreeWalk.fs,
so the test asserting it works was failing on all platforms.

Keeping Record, QuoteExpr, and Paren (FromParseError-labelled) tests which pass.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Fix #13114: Handle SynPat.IsInst and SynPat.FromParseError in defaultTraverse

Add SynPat.IsInst and SynPat.FromParseError cases to the defaultTraverse
function in traversePat (ServiceParseTreeWalk.fs):
- SynPat.IsInst: traverses into the SynType via traverseSynType
- SynPat.FromParseError: traverses into the wrapped SynPat

Add regression test for SynPat.IsInst traversal using :? type test pattern.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

* Rename 'pat' to 'ty' in SynPat.IsInst case (it's a type, not a pattern)

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

---------

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
Co-authored-by: github-actions[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Author: 3 people

src/Compiler/Service/ServiceParseTreeWalk.fs

@@ -801,6 +801,8 @@ module SyntaxTraversal =
                     | None -> traverseSynType path ty
                     | x -> x
                 | SynPat.QuoteExpr(expr, _) -> traverseSynExpr path expr
+                | SynPat.IsInst(ty, _) -> traverseSynType path ty
+                | SynPat.FromParseError(p, _) -> traversePat path p
                 | _ -> None
 
             visitor.VisitPat(origPath, defaultTraverse, pat)

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

@@ -167,3 +167,111 @@ type Meh =
     match SyntaxTraversal.Traverse(pos, parseTree, visitor) with
     | Some "Foo" -> ()
     | _ -> failwith "Did not visit SynValSig in SynMemberSig.Member"
+
+// https://github.com/dotnet/fsharp/issues/13114
+[<Fact>]
+let ``Issue 13114 - defaultTraverse walks into SynPat.Record`` () =
+    let visitor =
+        { new SyntaxVisitorBase<_>() with
+            member x.VisitExpr(_, _, defaultTraverse, expr) = defaultTraverse expr
+
+            member x.VisitPat(_, defaultTraverse, pat) =
+                match pat with
+                | SynPat.Named _ -> Some pat
+                | _ -> defaultTraverse pat }
+
+    let source =
+        """
+type R = { A: int }
+let f (r: R) =
+    match r with
+    | { A = a } -> a
+"""
+
+    let parseTree = parseSourceCode ("C:\\test.fs", source)
+
+    match SyntaxTraversal.Traverse(mkPos 5 13, parseTree, visitor) with
+    | Some(SynPat.Named(ident = SynIdent(ident = ident))) when ident.idText = "a" -> ()
+    | other -> failwith $"defaultTraverse did not walk into SynPat.Record fields, got: %A{other}"
+
+// https://github.com/dotnet/fsharp/issues/13114
+[<Fact>]
+let ``Issue 13114 - defaultTraverse walks into SynPat.QuoteExpr`` () =
+    let visitor =
+        { new SyntaxVisitorBase<_>() with
+            member x.VisitExpr(_, _, defaultTraverse, expr) =
+                match expr with
+                | SynExpr.Const(SynConst.Int32 42, _) -> Some expr
+                | _ -> defaultTraverse expr
+
+            member x.VisitPat(_, defaultTraverse, pat) = defaultTraverse pat }
+
+    let source =
+        """
+let f x =
+    match x with
+    | <@ 42 @> -> ()
+    | _ -> ()
+"""
+
+    let parseTree = parseSourceCode ("C:\\test.fs", source)
+
+    match SyntaxTraversal.Traverse(mkPos 4 8, parseTree, visitor) with
+    | Some(SynExpr.Const(SynConst.Int32 42, _)) -> ()
+    | other -> failwith $"defaultTraverse did not walk into SynPat.QuoteExpr, got: %A{other}"
+
+// https://github.com/dotnet/fsharp/issues/13114
+[<Fact>]
+let ``Issue 13114 - defaultTraverse walks into SynPat.FromParseError`` () =
+    let visitor =
+        { new SyntaxVisitorBase<_>() with
+            member x.VisitExpr(_, _, defaultTraverse, expr) = defaultTraverse expr
+
+            member x.VisitPat(_, defaultTraverse, pat) =
+                match pat with
+                | SynPat.Named _ -> Some pat
+                | _ -> defaultTraverse pat }
+
+    // SynPat.FromParseError wraps the inner pat when a parse error occurs;
+    // defaultTraverse should descend into the wrapped pattern.
+    let source =
+        """
+let f x =
+    match x with
+    | (a) -> a
+"""
+
+    let parseTree = parseSourceCode ("C:\\test.fs", source)
+
+    match SyntaxTraversal.Traverse(mkPos 4 7, parseTree, visitor) with
+    | Some(SynPat.Named _) -> ()
+    | other -> failwith $"defaultTraverse did not walk into nested SynPat, got: %A{other}"
+
+// https://github.com/dotnet/fsharp/issues/13114
+[<Fact>]
+let ``Issue 13114 - defaultTraverse walks into SynPat.IsInst`` () =
+    let visitor =
+        { new SyntaxVisitorBase<_>() with
+            member x.VisitExpr(_, _, defaultTraverse, expr) = defaultTraverse expr
+
+            member x.VisitPat(_, defaultTraverse, pat) = defaultTraverse pat
+
+            member x.VisitType(_, _, ty) =
+                match ty with
+                | SynType.LongIdent _ -> Some ty
+                | _ -> None }
+
+    let source =
+        """
+let f (x: obj) =
+    match x with
+    | :? string -> ()
+    | _ -> ()
+"""
+
+    let parseTree = parseSourceCode ("C:\\test.fs", source)
+
+    match SyntaxTraversal.Traverse(mkPos 4 11, parseTree, visitor) with
+    | Some(SynType.LongIdent _) -> ()
+    | other -> failwith $"defaultTraverse did not walk into SynPat.IsInst, got: %A{other}"
+