[libcxx-commits] [libcxx] [libc++] Avoid -Wzero-as-null-pointer-constant in operator<=> (PR #79465)

[Louis Dionne via libcxx-commits]

ldionne wrote:

Ok, so IIUC basically you need the `== 0` condition to be something that SFINAEs-away the overload. I'm not sure whether that's the case with `__diagnose_if__`, but maybe @cor3ntin has something to suggest? Maybe the `__enable_if` attribute?

https://github.com/llvm/llvm-project/pull/79465