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

[Dan Shan via libcxx-commits]

HumanThe2nd wrote:

> 1. Have you checked if the new tests pass without the change to the constraint? If they still pass, IMO these tests don't verify the change sufficiently.
> 2. Have you verified the change to the constraint? Does it do what it you expected it to do? Is there an improvment/any change in the compiler diagnostics?

I tested the code both with and without the change, and the new tests do pass in both cases. Though, I also wasn't able to reproduce the ambiguity from the documented example or similar cases, suggesting it's resolved elsewhere, possibly clang's template partial ordering. So this PR mandates wording of LWG4072, but doesn't fix a reproducible bug as originally suggested. Would appreciate thoughts on how to proceed, thanks. 

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