anchor.diff:          ElementRef,
           ChangeDetectorRef;
   import 'package:angular/di.dart' show Injectable;
  -import 'package:angular/src/core/linker/app_view_utils.dart';
   import 'package:angular/src/core/render/api.dart' show sharedStylesHost;
  -import 'package:angular/src/debug/debug_node.dart'
  -    show DebugElement, getDebugNode;
  -import 'package:angular/src/platform/dom/dom_tokens.dart' show DOCUMENT;
   import 'package:angular/src/platform/dom/shared_styles_host.dart';
  -
  -/// Fixture for debugging and testing a component.
  -class ComponentFixture {
  -  /// The DebugElement associated with the root element of this component.
  -  DebugElement _debugElement;
  -
  -  /// The instance of the root component class.
  -  dynamic componentInstance;
  -
  -  /// The native element at the root of the component.
  -  dynamic nativeElement;
  -
  -  /// The [ElementRef] for the element at the root of the component.
  -  ElementRef elementRef;
  -
  -  /// The [ComponentRef] for the component.
  -  ComponentRef componentRef;
  -
  -  /// The [ChangeDetectorRef] for the component.
  -  ChangeDetectorRef changeDetectorRef;
  -
  -  ComponentFixture(ComponentRef ref) {
  -    changeDetectorRef = ref.changeDetectorRef;
  -    elementRef = ref.location;
  -    _debugElement = (getDebugNode(elementRef.nativeElement) as DebugElement);
  -    componentInstance = ref.instance;
  -    assert(componentInstance != null);
  -    nativeElement = elementRef.nativeElement;
  -    componentRef = ref;
  -  }
  -
  -  DebugElement get debugElement {
  -    if (_debugElement == null) {
  -      throw new Exception(
  -          'DebugElement is not available in DART_CODEGEN_MODE=release');
  -    }
  -    return _debugElement;
  -  }
  -
  -  /// Trigger a change detection cycle for the component.
  -  void detectChanges([bool checkForNoChanges = true]) {
  -    AppViewUtils.resetChangeDetection();
  -    changeDetectorRef.detectChanges();
  -  }
  -
  -  /// Trigger component destruction.
  -  void destroy() {
  -    componentRef.destroy();
  -  }
  -}
   
   var _nextRootElementId = 0;
   
  
positive.code: import 'dart:async';
  import 'dart:html';
  
  import 'package:angular/core.dart'
  
negative.code:     var clone = _clone();
      return clone;
    }
  }
  