https://gcc.gnu.org/bugzilla/show_bug.cgi?id=97121
--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
Fixed on trunk by r11-5866
c++: Fix defaulted <=> fallback to < and == [PR96299]
I thought I had implemented P1186R3, but apparently I didn't read it
closely
enough to understand the point of the paper, namely that for a defaulted
operator<=>, if a member type doesn't have a viable operator<=>, we will
use
its operator< and operator== if the defaulted operator has an specific
comparison category as its return type; the compiler can't guess if it
should be strong_ordering or something else, but the user can make that
choice explicit.
The libstdc++ test change was necessary because of the change in
genericize_spaceship from op0 > op1 to op1 < op0; this should be
equivalent,
but isn't because of PR88173.
We should add a test and close it.
