Sadly `if constexpr (requires {})` was not implemented in MSVC until VS2022, which was not even released when I tried using it and backed out because it wouldn'

Sadly `if constexpr (requires {})` was not implemented in MSVC until VS2022, which was not even released when I tried using it and backed out because it wouldn't build on MSVC, and is still a new and less-adopted compiler than 2019: https://developercommunity.visualstudio.com/t/requires-clause-in-constexpr-if-doesnt-work/929394 https://developercommunity.visualstudio.com/t/requires-claus...