class C extends Object {
  //no errors in this foo method
  Object foo(Object o) {
    C2 v2;
    v2 = new C2();  //no error, returns the new v2 of type C2
  }
}
class C2 extends C {
  //error in this foo method:
  // a superclass has a method with the same name but 
  //   different return type
  C2 foo(Object o) {
    C2 v;
    v = new C2(); 
  }
}
main {
  0;
}