https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92806
--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
This seems to be fixed now:
a.C:8:9: required by the constraints of 'template<class T> concept foo'
a.C:8:25: error: constraint 'trait<T>::value [with T = int]' has type
'trait<int>::<unnamed enum>', not 'bool'
8 | concept foo = trait<T>::value;
| ^~~~~
a.C:10:15: error: non-constant condition for static assertion
10 | static_assert(foo<int>);
| ^~~~~~~~
a.C:8:9: required by the constraints of 'template<class T> concept foo'
a.C:8:25: error: constraint 'trait<T>::value [with T = int]' has type
'trait<int>::<unnamed enum>', not 'bool'
8 | concept foo = trait<T>::value;
| ^~~~~
