You can't use "if constexpr" to vary the type signature, for example (as in my link). Or to choose a different representation for a type based on a type parame

You can't use "if constexpr" to vary the type signature, for example (as in my link). Or to choose a different representation for a type based on a type parameter. Those will require metaprogramming at the template level. Another example: you can't write std::is_same_v itself using "if constexpr".