interface Moogie [T]  { }

interface IBuggy [+P, -M] {
  Get (i : int) : M; // E: return type of method `Get' must behave covariantly
  IsEmpty : Moogie [M] { get; }; // E: return type of method `get_IsEmpty' must behave covariantly
  
  Set (x : P) : void; // E: type of `Set' method's parameter `x' must behave contravariantly
  
  MeGene ['a] (x : int) : void where 'a : P; // E: constraints of generic parameters of method `MeGene' must behave contravariantly
}

public interface ICovariantEnumerator [+T]
{
  MoveNext () : bool;
  Current : T { get; }
}

public interface ICovariantEnumerable [+T]
{
  GetEnumerator () : ICovariantEnumerator [T];
  SetEnumerator(e : ICovariantEnumerator [T]) : void; // E: type of `SetEnumerator' method's parameter `e' must behave contravariantly
  SetArray (x : array [T]) : void; // E: type of `SetArray' method's parameter `x' must behave contravariantly
}


interface ICovariantSubEnumerable [+T] : System.Collections.Generic.IEnumerable[T] {  // E: incorrect usage of generic parameters in.* supertypes must behave covariantly
}
    

()