Thanks, this looks solid! The only things I noticed were stylistic nitpicks, so I went ahead and pushed a merge with main followed by those trivial changes, after validating that the relevant tests still pass.

Thanks - I approve of the ternary-to-if change that @barcharcraz requested, as if this test ever fails, the asserting line will indicate what was expected - same as the rationale for preferring assert(is_cute()); assert(is_fluffy()); assert(is_kitten()); on separate lines instead of assert(is_cute() && is_fluffy() && is_kitten());.

I'm mirroring this to the MSVC-internal repo - please notify me if any further changes are pushed.

Thanks for syncing the implementation with the Standard's stream of LWG issues! 😹 🚀 🎉