template <class T, class U> constexpr auto operator*(T lhs, U rhs) -> std::enable_if_t<stlab::implementation::has_enabled_arithmetic<T> && stlab::implementation::is_convertible_to_underlying<U, T>::value, T> (1) template <class U, class T> constexpr auto operator*(U lhs, T rhs) -> std::enable_if_t<stlab::implementation::has_enabled_arithmetic<T> && stlab::implementation::is_convertible_to_underlying<U, T>::value, T> (2) (1) template <class T, class U> constexpr auto operator*(T lhs, U rhs) -> std::enable_if_t<stlab::implementation::has_enabled_arithmetic<T> && stlab::implementation::is_convertible_to_underlying<U, T>::value, T> MISSING Parameters T lhs U rhs (2) template <class U, class T> constexpr auto operator*(U lhs, T rhs) -> std::enable_if_t<stlab::implementation::has_enabled_arithmetic<T> && stlab::implementation::is_convertible_to_underlying<U, T>::value, T> MISSING Parameters U lhs T rhs