[libcxx-commits] [libcxx] [libc++] Add __detected_or_t and use it to implement some of the allocator traits aliases (PR #115654)

[via libcxx-commits]

cmtice wrote:

(I could add it to some of the other 'using' statements, too, and reduce it further)

https://github.com/llvm/llvm-project/pull/115654