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>();