!7

cprint {
  class A {
    swappable S x() { ret "a"; }
  }
  
  class B extends A {
    swappable S x_inner() { ret super.x_base(); }
    S x_base() { ret "b" + x_inner(); }
  }
  
  start-thread {
    assertEqualsVerbose("a", new A().x());
    assertEqualsVerbose("ba", new B().x());
    
    // override the whole x() method
    new B c;
    c.x = () -> "c";
    assertEqualsVerbose("c", c.x());
    
    // override the A.x() method while keeping B's added logic
    c = new B;
    c.x_inner = () -> "c";
    assertEqualsVerbose("bc", c.x());
  }
}