https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96489
--- Comment #5 from DV Henkel-Wallace <gu...@henkel-wallace.org> --- (In reply to Jonathan Wakely from comment #4) > I believe the rationale for this is that if your <=> can't be defaulted, > then it must be doing something special, and synthesizing == from it is not > necessarily safe. The thing is: properly written user defined operator <=> is supposed to to be "correct" (whatever that would mean!) for all of the < 0, = 0, and > 0 cases. It doesn't make sense to presume that a user defined <=> would only apply to the < and > cases -- in fact how could it otherwise synthesize <= and => ? (More jocularly it's not `operator <>` -- would we call that the submarine operator?) In fact I just changed my test case to use `((a <=> b) != 0)` and it did what I expected. > Clang agrees with GCC FWIW. Yes, reported it to them too :-(
