[Bug c++/95242] [10/11 Regression] spurious "warning: zero as null pointer constant [-Wzero-as-null-pointer-constant]" on comparisons with -std=c++2a

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95242

--- Comment #6 from Jonathan Wakely <redi at gcc dot gnu.org> ---
It was just a sketch to show the idea.

Obviously the real thing would need noexcept, but we have a regression test for
that. How to construct it is what's relevant here.