Does not compile under MSVC 2019 about patterns HOT 1 OPEN

#ifdef _MSVC_LANG
#  define MP_CPLUSPLUS _MSVC_LANG
#else
#  define MP_CPLUSPLUS __cplusplus
#endif

#if MP_CPLUSPLUS < 201703L
#error "MPark.Patterns requires C++17 support."
#endif

#ifdef __GNUG__
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wmissing-field-initializers"
#endif
  template <typename T,
            std::size_t... Is,
            typename = decltype(T{(Is, fill{})...})>
  constexpr bool is_n_constructible(std::index_sequence<Is...>,
                                    lib::priority<0>) {
    return true;
  }
#ifdef __GNUG__
#pragma GCC diagnostic pop
#endif