Fix off-by-one error in PPCaching.cpp token annotation assertion

This assert is intended to defend against backtracking into the middle
of a sequence of tokens that is being replaced with an annotation, but
it's OK if we backtrack to the exact position of the start of the
annotation sequence. Use a <= comparison instead of <.

Fixes PR25946

llvm-svn: 284777

1 files changed, 1 insertions, 1 deletions

diff --git a/clang/lib/Lex/PPCaching.cpp b/clang/lib/Lex/PPCaching.cpp
index 4742aae5c12..ae07ea9bcfd 100644
--- a/clang/lib/Lex/PPCaching.cpp
+++ b/clang/lib/Lex/PPCaching.cpp
@@ -105,7 +105,7 @@ void Preprocessor::AnnotatePreviousCachedTokens(const Token &Tok) {
   for (CachedTokensTy::size_type i = CachedLexPos; i != 0; --i) {
     CachedTokensTy::iterator AnnotBegin = CachedTokens.begin() + i-1;
     if (AnnotBegin->getLocation() == Tok.getLocation()) {
-      assert((BacktrackPositions.empty() || BacktrackPositions.back() < i) &&
+      assert((BacktrackPositions.empty() || BacktrackPositions.back() <= i) &&
              "The backtrack pos points inside the annotated tokens!");
       // Replace the cached tokens with the single annotation token.
       if (i < CachedLexPos)