boost::openmethod::virtual_ptr<SmartPtr, Registry>::cast

template<class Other>
requires std::is_base_of_v<element_type, Other> ||
            std::is_base_of_v<Other, element_type>
decltype(auto)
cast() &;

template<class Other>
requires std::is_base_of_v<element_type, Other> ||
            std::is_base_of_v<Other, element_type>
decltype(auto)
cast() const &;

template<class Other>
decltype(auto)
cast() &&;