option1.dart

class Super {
  bool get isSub => false;
  
  void doAThing() {
    if (isSub) throw "no";
    // ...
  }
}

class Sub extends Super {
  bool get isSub => true;
}

option2.dart

class Super {
  void doAThing() {
    // ...
  }
}

class Sub extends Super {
  void doAThing() {
    throw "no";
  }
}