[libcxx-commits] [libcxx] [libc++] Allow a disengaged `optional` to be `constexpr` since C++20 (PR #192888)

[Vlad Serebrennikov via libcxx-commits]

Endilll wrote:

IIUC CWG2424 is about this example: https://godbolt.org/z/KoK9P5aYG
As you can see, it's still not backported to C++17 or earlier modes, but has been available in C++20 mode since Clang 10, i.e. for 6 or 7 years at this point.

https://github.com/llvm/llvm-project/pull/192888