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

[Louis Dionne via libcxx-commits]

ldionne wrote:

@cmtice If you open a PR, our CI will tell you if you messed up badly enough to break something else :). That should be sufficient for a patch of this kind.

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