On Fri, 4 Jun 2021 at 21:41, Jonathan Wakely wrote:
>
> On Thu, 3 Jun 2021 at 17:27, Seija K. via Libstdc++ <libstdc++@gcc.gnu.org>
> wrote:
>
> > The original operator was underconstrained. _Up needs to fulfill
> > compare_three_way_result,
> > as mentioned in this bug report
> > https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98842
> >
>
> Thanks, I'll get the patch applied next week.

The patch causes testsuite failures.

I fixed it with the attached change instead, including a workaround
for an apparent C++20 defect.

Pushed to trunk so far.