[clang] [Clang] disallow attributes after namespace identifier (PR #121614)

[Oleksandr T. via cfe-commits]

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@@ -100,7 +103,7 @@ Parser::DeclGroupPtrTy Parser::ParseNamespace(DeclaratorContext Context,
     } while (MoreToParse);
   };
 
-  ReadAttributes();
+  ReadAttributes(/*TrailingAttrs*/ false);
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a-tarasyuk wrote:

@cor3ntin is it acceptable to use `DiagnoseAndSkipCXX11Attributes` to reduce errors list?

https://github.com/llvm/llvm-project/pull/121614