https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110580
--- Comment #4 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
Slightly more reduced:
```
#include <type_traits>
using std::is_same_v;
struct s0 {};
struct s1 {};
template <typename _Key>
struct s3 {
template <typename _Up, typename _Vp = _Up>
static constexpr bool __usable_key = is_same_v<_Vp, _Key>;
static_assert(!__usable_key<s1>);
};
s3<s0> t;
```
If I remove _Vp or remove it from being type dependent, it works.
