import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;
@NullMarked
public class Test {
  class A<X extends @Nullable Object> {
    class B<Y extends @Nullable Object> {}
  }
  class C<X extends @Nullable Object> extends A<X> {
    class D<Y extends @Nullable Object> extends A<X>.B<Y> {}
  }
  void test() {
    C<@Nullable String> c = new C<>();
    A<String>.B<@Nullable String> unused = c.new D<@Nullable String>();
  }
}