anchor.diff:    void set setter(String v) {}
     void set m(String v) {}
     String method(int i) => "Extension: $i";
  -  void operator[]=(int index, String value) {}
  +  void operator []=(int index, String value) {}
   }
   
   main() {
     C? c = new C();
  -  Expect.equals("C getter", c.getter);
  +  Expect.equals("Extension getter", c.getter);
     c.m = "Lily was here";
  -  Expect.equals("Lily was here", c.m);
  +  Expect.equals("m getter", c.m);
     c.setter = "Run, Forrest, run";
  -  Expect.equals("Run, Forrest, run", c.m);
  -  Expect.equals("42", c.method(42));
  -  c[42]="xxx";
  -  Expect.equals("[42]=xxx", c.m);
  +  Expect.equals("m getter", c.m);
  +  Expect.equals("Extension: 42", c.method(42));
  +  c[42] = "xxx";
  +  Expect.equals("m getter", c.m);
   }
  
positive.code:  * considered accessible (and hence which take precedence over extensions) are
   * the members on Object.
   *
   * @description Check that instance members have precedence over extension
   * members of nullable type
   * @author sgrekhov@unipro.ru
   * @issue 41349
   */
  
negative.code:   void set setter(String v) {
      m = v;
    }
  
    String method(int i) => "$i";
    void operator []=(int index, String value) {
      m = "[$index]=$value";
    }
  }
  