[clang] [Clang] Fix infinite loop on '::' inside parens in C mode (PR #195377)

[Aaron Ballman via cfe-commits]

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@@ -5629,6 +5632,8 @@ bool Parser::isTypeSpecifierQualifier(const Token &Tok) {
     return isTypeSpecifierQualifier(getCurToken());
 
   case tok::coloncolon:   // ::foo::bar
+    if (!getLangOpts().CPlusPlus && !getLangOpts().ObjC)
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AaronBallman wrote:

So why the `&& !ObjC` check? If ObC is true, we go on to check for `::new`, etc and won't that hit the same infinite loop when we check for type specifiers after annotation tokens?

Shouldn't we look to see whether `TryAnnotateTypeOrScopeToken()` created an annotation token before recursing instead of looking at language modes?

https://github.com/llvm/llvm-project/pull/195377