If you refer to `if constexpr`: There is no dark magic. Most of it is already possible with C++11 meta programming (i.e. with std::enable_if [0]). However, it's much more readable now (and it's more fun to write :D). I think we're on a good way that compile time programming will be more easily accessible.
[0] https://en.cppreference.com/w/cpp/types/enable_if