[clang] [clang] Warn about deprecated volatile-qualified return types (PR #137899)

[Mariya Podchishchaeva via cfe-commits]

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@@ -231,6 +231,13 @@ namespace DeprecatedVolatile {
     a = c = a;
     b += a;
   }
+
+  volatile struct amber jurassic();
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Fznamznon wrote:

As I can see, if the return type is not a struct/class, the warning is issued. Could you please add a test case with volatile qualifier applied to a basic type (for example int) and make sure there is no double diagnostic issued now?

https://github.com/llvm/llvm-project/pull/137899