[libcxx-commits] [libcxx] [libc++] Add `__is_transparently_comparable_v` specializations for `basic_string_view` (PR #195871)

[Louis Dionne via libcxx-commits]

ldionne wrote:

> This introduces an extension: https://godbolt.org/z/xej3Ez54T

It is true that this introduces an extension IIUC, specifically `map<string, V>::find(string_view)` is not supposed to compile but it does after this patch. On the other hand, it does make sense to say that `string` and `string_view` are transparently comparable, I think. And doing so might widen the applicability of other optimizations? Perhaps what we need here is to gate the overloads of `map::find` on more than just `is_transparently_comparable`, but still take part of this patch?

https://github.com/llvm/llvm-project/pull/195871