object Test { def M[N[O[_]]] = () type A[_] = Any type B[_[_]] = Any type C[_[_[_]]] = Any M[Any] // okay, Any is kind overloaded. M[AnyRef] // error, (AnyRef :: *) not kind-conformant to (N :: * -> * -> *) M[A] // error, (A :: (* -> *) not kind-conformant to (N :: * -> * -> *) M[B] // okay, (B :: (* -> * -> *) is kind-conformant to (N :: * -> * -> *) M[C] // error, (C :: (* -> * -> * -> *) not kind-conformant to (N :: * -> * -> *) }