[clang] [clang][Sema] Fix type of an statement expression ending with an atomic type (PR #119711)

[Alejandro Álvarez Ayllón via cfe-commits]

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@@ -15919,10 +15919,17 @@ ExprResult Sema::ActOnStmtExprResult(ExprResult ER) {
   if (Cast && Cast->getCastKind() == CK_ARCConsumeObject)
     return Cast->getSubExpr();
 
+  auto Ty = E->getType().getUnqualifiedType();
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alejandro-alvarez-sonarsource wrote:

> So my suggestion is that common functions like getUnqualifiedType() should just be looking through _Atomic, which would have fixed this bug before it happened. 

While I understand the reasoning, I am wary of touching a method that is used (roughly counted) over 400 times. Unfortunately, I do not currently have the bandwith to commit into carefully combing all of them.

https://github.com/llvm/llvm-project/pull/119711