https://gcc.gnu.org/bugzilla/show_bug.cgi?id=89612
--- Comment #2 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Reduced (invalid):
template <int> bool b;
template <typename>
struct C {
template <typename> friend int foo() noexcept(b<1>);
};
template <typename> int foo() noexcept(b<1>);
auto a = C<int>();
