[clang] [clang][Parser] Warn when the body of expansion statement is not a compound statement (PR #209229)

[via cfe-commits]

================
@@ -1,4 +1,5 @@
 // RUN: %clang_cc1 %s -std=c++2c -fsyntax-only -verify
+// RUN: %clang_cc1 %s -std=c++2c -fsyntax-only -verify=expected,brace -Wexpansion-stmt-braced-body
----------------
Sirraide wrote:

Can you put a test for this warning in a separate file; because this file gets pretty messy otherwise...

https://github.com/llvm/llvm-project/pull/209229