concept Comparable<U> {
  fun compare(U x, U y) -> bool@;
};

fun min<T> where { Comparable<T> }
(T x, T y) -> T
{
  if (model Comparable<T>.compare(x, y))
    return x;
  else
    return y; 
}

model Comparable<int> {
  fun compare(int x, int y) -> bool@ {
    return x < y;
  }
};

fun main() -> int@ {
  return min(1, 0);
}