[clang] [Clang] add emit -Wignored-cv-qualifiers diagnostic for cv-qualified base classes (PR #132116)

[Erich Keane via cfe-commits]

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@@ -284,6 +284,8 @@ Improvements to Clang's diagnostics
 
 - Improve the ``-Wundefined-func-template`` warning when a function template is not instantiated due to being unreachable in modules.
 
+- Clang now emits a ``-Wignored-cv-qualifiers`` diagnostic when a base class includes cv-qualifiers ([toadd]).
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erichkeane wrote:

what is `[toadd]`? 

https://github.com/llvm/llvm-project/pull/132116