[clang] [clang] Warn [[clang::lifetimebound]] misusages on types (PR #118281)

[Maksim Ivanov via cfe-commits]

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@@ -8612,7 +8612,10 @@ static void HandleLifetimeBoundAttr(TypeProcessingState &State,
     CurType = State.getAttributedType(
         createSimpleAttr<LifetimeBoundAttr>(State.getSema().Context, Attr),
         CurType, CurType);
+    return;
   }
+  State.getSema().Diag(Attr.getLoc(), diag::err_attribute_not_type_attr)
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emaxx-google wrote:

Done, makes sense!

Probably I should also change the existing diagnostics on the decl-spec code? (This is the `int [[clang::lifetimebound]]` test above.) I'll do that in a separate PR because this would be a change of the warning that was already emitted previously.

https://github.com/llvm/llvm-project/pull/118281