I'm 90% sure this used to show warnings, but now the flutter analyze gives the following code a clean bill of health:

abstract class A {
  void test1() { }
  void test2();
}

class B extends A {
  void test1() { }
  void test2() { }
}

void main() { }

I would have expected two warnings, one on B.test1 and one on B.test2, both saying that @override was missing.

cc @pq, @danrubel