[clang] [clang] Fix comma location tracking inside ParenListExpr. (PR #199411)

[Erich Keane via cfe-commits]

================
@@ -4250,7 +4250,9 @@ class Parser : public CodeCompletionHandler {
   ///         assignment-expression
   ///         simple-expression-list , assignment-expression
   /// \endverbatim
-  bool ParseSimpleExpressionList(SmallVectorImpl<Expr *> &Exprs);
+  bool ParseSimpleExpressionList(
+      SmallVectorImpl<Expr *> &Exprs,
+      SmallVectorImpl<SourceLocation> *CommaLocs = nullptr);
----------------
erichkeane wrote:

I think we should never make this optional, make it always a reference, and if some AST nodes skip saving them, that is acceptable.

https://github.com/llvm/llvm-project/pull/199411