[libcxx-commits] [libcxx] [libc++] P2641R4: Checking if a `union` alternative is active (`std::is_within_lifetime`) (PR #107450)

[Louis Dionne via libcxx-commits]

https://github.com/ldionne requested changes to this pull request.

Thanks for the patch! I have some comments about the form, but the patch itself makes sense to me.

https://github.com/llvm/llvm-project/pull/107450