[Bug c++/92268] Constraint normalization substitutes parameter too early

[redi at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92268

--- Comment #1 from Jonathan Wakely <redi at gcc dot gnu.org> ---
The workaround is to require that the common_reference_t types exist:

template<typename T, typename U>
  concept common_reference_with
    =  
// <INS>
   requires { typename common_reference_t<T, U>;
              typename common_reference_t<U, T>; }
   &&
// </INS>
foo<common_reference_t<T, U>, common_reference_t<U, T>>
    && bar<common_reference_t<T, U>, common_reference_t<U, T>>
    && baz<common_reference_t<T, U>, common_reference_t<U, T>>;