[clang] [Clang] [C++26] Implement P1306R5 Expansion Statements (PR #165195)

[via cfe-commits]

================
@@ -416,9 +420,10 @@ def warn_cxx98_compat_for_range : Warning<
   "range-based for loop is incompatible with C++98">,
   InGroup<CXX98Compat>, DefaultIgnore;
 def err_for_range_identifier : Error<
-  "range-based for loop requires type for loop variable">;
+  "%select{range-based for loop|expansion statement}0 requires "
----------------
Sirraide wrote:

There’s only 2 combinations because both `%select`s use index `0`; I’m assuming the for-range code has a test for the first option, and I *should* have one for the second option somewhere; if not I’ll add one.

https://github.com/llvm/llvm-project/pull/165195