Fix this:

With this snippet:
  void f(a::b);

An assert is hit:
Assertion failed: CachedTokens[CachedLexPos-1].getLocation() == Tok.getAnnotationEndLoc() && "The annotation should be until the most recent cached token", file ..\..\lib\Lex\PPCaching.cpp, line 98

Introduce Preprocessor::RevertCachedTokens that reverts a specific number of tokens when backtracking is enabled.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@59636 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 12 insertions, 6 deletions

diff --git a/lib/Parse/Parser.cpp b/lib/Parse/Parser.cpp
index 86526cc158..861609ce75 100644
--- a/lib/Parse/Parser.cpp
+++ b/lib/Parse/Parser.cpp
@@ -731,9 +731,12 @@ void Parser::TryAnnotateTypeOrScopeToken() {
 
   if (SS.isNotEmpty()) {
     // A C++ scope specifier that isn't followed by a typename.
-    // Push the current token back into the token stream and use an annotation
-    // scope token for current token.
-    PP.EnterToken(Tok);
+    // Push the current token back into the token stream (or revert it if it is
+    // cached) and use an annotation scope token for current token.
+    if (PP.isBacktrackEnabled())
+      PP.RevertCachedTokens(1);
+    else
+      PP.EnterToken(Tok);
     Tok.setKind(tok::annot_cxxscope);
     Tok.setAnnotationValue(SS.getScopeRep());
     Tok.setAnnotationRange(SS.getRange());
@@ -754,9 +757,12 @@ void Parser::TryAnnotateScopeToken() {
     CXXScopeSpec SS;
     ParseCXXScopeSpecifier(SS);
 
-    // Push the current token back into the token stream and use an annotation
-    // scope token for current token.
-    PP.EnterToken(Tok);
+    // Push the current token back into the token stream (or revert it if it is
+    // cached) and use an annotation scope token for current token.
+    if (PP.isBacktrackEnabled())
+      PP.RevertCachedTokens(1);
+    else
+      PP.EnterToken(Tok);
     Tok.setKind(tok::annot_cxxscope);
     Tok.setAnnotationValue(SS.getScopeRep());
     Tok.setAnnotationRange(SS.getRange());