RequireMethod.hpp

#include <type_traits>

#define REQUIRE(method, ...)                                             \
    template <typename Cont, typename = void>                            \
    struct require_##method : std::false_type {};                        \
    template <typename Cont>                                             \
    struct require_##method<                                             \
        Cont,                                                            \
        std::void_t<decltype(std::declval<Cont>().method(__VA_ARGS__))>> \
        : std::true_type {};                                             \
    template <typename T>                                                \
    constexpr bool require_##method##_v = valid_##method<T>::value;

#define VAL(T) std::declval<T>()