anchor.diff:      super.field = null;
     }
   }
  + 
  +method1() {} // Deliberately the same name as the instance member in Mixin.
   
  +@NoInline()
   main() {
     print('Hello World');
     ''.contains; // Trigger member closurization.
  
positive.code:   new Class2().method2();
    new Class2().method3();
    new Class2().method5();
  }
  '''
  };
  
negative.code: 
  const SOURCE = const {
    'main.dart': '''
  import 'dart:html';
  import 'package:expect/expect.dart';
  
  class ClassWithSetter {
    void set setter(_) {}
  