we do in fact have to cache the EOF token returned by the preprocessor.

In the case of backtracking, the cached token lexer will be the only 
lexer on the stack, without this the token stack will be empty and EOF
won't be returned.

This fixes PR7072.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@108124 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Lex/PPCaching.cpp

@@ -60,13 +60,10 @@ void Preprocessor::CachingLex(Token &Result) {
     return;
   }
 
-  // We should cache the lexed token.
-
+  // Cache the lexed token.
   EnterCachingLexMode();
-  if (Result.isNot(tok::eof)) {
-    CachedTokens.push_back(Result);
-    ++CachedLexPos;
-  }
+  CachedTokens.push_back(Result);
+  ++CachedLexPos;
 }
 
 void Preprocessor::EnterCachingLexMode() {

test/Parser/backtrack-crash.cpp

+// RUN: %clang_cc1 %s -fsyntax-only -verify -pedantic
+// PR7072
+()( // expected-error {{expected unqualified-id}}
+