anchor.diff:  
   var helloGreeter = react.registerComponent(() => new _HelloGreeter());
   
  -class _CheckBoxComponent extends react.Component2 {
  +class _CheckBoxComponent extends react.Component {
     getInitialState() => {"checked": false};
   
     change(e) {
  
positive.code: 
  var checkBoxComponent = react.registerComponent(() => new _CheckBoxComponent());
  
  class _ClockComponent extends react.Component2 {
    Timer timer;
  
    getInitialState() => {'secondsElapsed': 0};
  
negative.code: 
  var listComponent = react.registerComponent(() => new _ListComponent());
  
  class _MainComponent extends react.Component {
    render() {
      return react.div({}, props['children']);
    }
  