void hello(int) {}

template<class Signature, class...Args>
void check(Signature&& callable, Args&&...args)
{
  std::cout << std::boolalpha;

  std::cout << typeid(Signature).name() << std::endl;
  std::cout << typeid(void(Args...)).name() << std::endl;
  std::cout << typeid(std::decay_t<Signature>).name() << std::endl;
  std::cout << typeid(std::decay_t<void(Args...)>).name() << std::endl;

  std::cout << std::is_same<Signature, void(Args...)>::value << std::endl;
  std::cout << std::is_same<Signature, void(Args...)>::value << std::endl;
  std::cout << std::is_same<std::decay_t<Signature>, std::decay_t<void(Args...)>>::value << std::endl;
}

check(hello, 1);