[clang] [Clang][Sema] Reject invalid member using-declaration whose nested-name-specifier doesn't refer to a base class of the current class in C++98 mode (PR #143492)

[Vlad Serebrennikov via cfe-commits]

================
@@ -159,6 +159,11 @@ Resolutions to C++ Defect Reports
 
 - Implemented `CWG2496 ref-qualifiers and virtual overriding <https://wg21.link/CWG2496>`_.
 
+- Fully implemented `CWG400 Using-declarations and the "struct hack" `
+  `<https://wg21.link/CWG400>`_. Correctly rejected invalid member
----------------
Endilll wrote:

```suggestion
  `<https://wg21.link/CWG400>`_. Correctly reject invalid member
```

https://github.com/llvm/llvm-project/pull/143492