1 files changed, 23 insertions, 15 deletions

diff --git a/lib/Parse/ParseInit.cpp b/lib/Parse/ParseInit.cpp
index 7742a5087cf01..7a455484b902f 100644
--- a/lib/Parse/ParseInit.cpp
+++ b/lib/Parse/ParseInit.cpp
@@ -1,9 +1,8 @@
 //===--- ParseInit.cpp - Initializer Parsing ------------------------------===//
 //
-//                     The LLVM Compiler Infrastructure
-//
-// This file is distributed under the University of Illinois Open Source
-// License. See LICENSE.TXT for details.
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
 //
 //===----------------------------------------------------------------------===//
 //
@@ -66,15 +65,28 @@ bool Parser::MayBeDesignationStart() {
 
   // Parse up to (at most) the token after the closing ']' to determine
   // whether this is a C99 designator or a lambda.
-  TentativeParsingAction Tentative(*this);
+  RevertingTentativeParsingAction Tentative(*this);
 
   LambdaIntroducer Intro;
-  bool SkippedInits = false;
-  Optional<unsigned> DiagID(ParseLambdaIntroducer(Intro, &SkippedInits));
+  LambdaIntroducerTentativeParse ParseResult;
+  if (ParseLambdaIntroducer(Intro, &ParseResult)) {
+    // Hit and diagnosed an error in a lambda.
+    // FIXME: Tell the caller this happened so they can recover.
+    return true;
+  }
+
+  switch (ParseResult) {
+  case LambdaIntroducerTentativeParse::Success:
+  case LambdaIntroducerTentativeParse::Incomplete:
+    // Might be a lambda-expression. Keep looking.
+    // FIXME: If our tentative parse was not incomplete, parse the lambda from
+    // here rather than throwing away then reparsing the LambdaIntroducer.
+    break;
 
-  if (DiagID) {
-    // If this can't be a lambda capture list, it's a designator.
-    Tentative.Revert();
+  case LambdaIntroducerTentativeParse::MessageSend:
+  case LambdaIntroducerTentativeParse::Invalid:
+    // Can't be a lambda-expression. Treat it as a designator.
+    // FIXME: Should we disambiguate against a message-send?
     return true;
   }
 
@@ -83,11 +95,7 @@ bool Parser::MayBeDesignationStart() {
   // lambda expression. This decision favors lambdas over the older
   // GNU designator syntax, which allows one to omit the '=', but is
   // consistent with GCC.
-  tok::TokenKind Kind = Tok.getKind();
-  // FIXME: If we didn't skip any inits, parse the lambda from here
-  // rather than throwing away then reparsing the LambdaIntroducer.
-  Tentative.Revert();
-  return Kind == tok::equal;
+  return Tok.is(tok::equal);
 }
 
 static void CheckArrayDesignatorSyntax(Parser &P, SourceLocation Loc,