[libcxx-commits] [libcxx] [libc++] Implement LWG4072: std::optional comparisons: constrain harder (PR #209968)

[Dan Shan via libcxx-commits]

HumanThe2nd wrote:

> @HumanThe2nd I'm implementing LWG4072 for MSVC STL in [microsoft/STL#6424](https://github.com/microsoft/STL/pull/6424) now. I think you can copy these relative test cases.
> 
> @jwakely Thanks again for finding these cases out!

Thank you for providing the references and explanations.

I've integrated them into this PR, attempting to match the architecture here. (credit @frederick-vs-ja and @jwakely)

The local tests fail all assertions without the LWG4072 changes and pass with them included.

If someone could review again, it would be appreciated. 

https://github.com/llvm/llvm-project/pull/209968