[clang] [Clang][Sema] Reject undeduced static data members without initializers (#173349) (PR #174281)

[Yanzuo Liu via cfe-commits]

zwuis wrote:

Please add a release note entry to "clang/docs/ReleaseNotes.rst".

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We already diagnose correctly if we move `E` and `v` out of templates. Can you merge these logic?

https://github.com/llvm/llvm-project/pull/174281