Function _canonicalize

include/exec/function.hpp:244–249

    template <template <class...> class List, class... Types>
    consteval auto _canonicalize(List<Types...> *) noexcept
    {
      using types_t        = __static_vector<__type_index, sizeof...(Types)>;
      constexpr auto types = _func::_canonicalize_impl(types_t{__mtypeid<Types>...});
      return _func::_canonicalize_splice<types, List>(__make_indices<types.size()>());
    }

    template <class Sigs>
    using _canonical_t = decltype(_func::_canonicalize(static_cast<Sigs *>(nullptr)));