Also backport - support for `T::value` of a reference type in `integral-constant-like` from P2781R9 `std::constant_wrapper`, and - LWG4351 _`integral-constant-like`_ needs more `remove_cvref_t`. P3029R1 (and its further fixes) should be treated as a Defect Report against C++20/23 to avoid behavior difference in different modes. Other implementations will do or are already doing the same.