[Bug c++/92099] [9/10 Regression] static_assert of struct template of false_type succeed with GCC8 but not GCC9

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=92099

--- Comment #3 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Reduced:

template <typename _Tp, _Tp __v> struct A { static constexpr _Tp value = __v;
};
typedef A<bool, false> false_type;
template <typename> struct DependentFalse : false_type {};
enum class E;
template <E id> void fn1() {
  static_assert(DependentFalse<decltype(id)>::value);
}