text: #include <iostream>
  #include <type_traits>
  template <class T>
  void F(T &) { std::cout << std::is_const<T>{}(); }
  int main() {
      std::cout << std::boolalpha;
      const int &i0 = 1;
      int i = 0;
      int &i1 = i;
      F(i0);
      F(i1);
  }
  