struct S
{
    using Fn = void();
    Fn foo;

    static_assert(std::is_same_v<decltype(foo), Fn>);
};

struct U
{
    int i;
    static_assert(std::is_same_v<decltype(i), int>);
};

template<typename>
struct NotLikeThis;
template<typename C, typename R, typename... Args>
struct NotLikeThis<R (C::*)(Args...)>
{
    using type = R(Args...);
};