integral-constant-like(C++26)

template<class T>
concept integral-constant-like =  // exposition only
  is_integral_v<decltype(T::value)> &&
  !is_same_v<bool, remove_const_t<decltype(T::value)>> &&
  convertible_to<T, decltype(T::value)> &&
  equality_comparable_with<T, decltype(T::value)> &&
  bool_constant<T() == T::value>::value &&
  bool_constant<static_cast<decltype(T::value)>(T()) == T::value>::value;