undecidable type comparison

public class Test1 {

    interface Type<T> {}

    class C implements Type<Type<? super C>> {}

    class D<P> implements Type<Type<? super D<D<P>>>> {}

    class Test {
        Type<? super C> c = new C();
        Type<? super D<Byte>> d = new D<Byte>();
    }

}