anchor.diff:     * error is real).
      */
     setValidity(NgControl control, String errorType, bool isValid) {
  -    List queue = currentErrors[errorType];
  +    List queue = errors[errorType];
   
       if(isValid) {
         if(queue != null) {
           queue.remove(control);
           if(queue.isEmpty) {
  -          currentErrors.remove(errorType);
  -          if(currentErrors.isEmpty) valid = true;
  +          errors.remove(errorType);
  +          if(errors.isEmpty) valid = true;
             _parentForm.setValidity(this, errorType, true);
           }
         }
       } else {
         if(queue == null) {
           queue = new List<NgControl>();
  -        currentErrors[errorType] = queue;
  +        errors[errorType] = queue;
           _parentForm.setValidity(this, errorType, false);
         } else if(queue.contains(control)) return;
   
  
positive.code: class NgNullForm implements NgForm {
    var _name, _dirty, _valid, _invalid, _pristine, _element;
    var _controls, _scope, _parentForm, _controlName;
    var currentErrors, _controlByName;
    dom.Element element;
    NgNullForm() {}
    operator[](name) {}
  
negative.code:   final dom.Element _element;
    final Scope _scope;
  
    final Map<String, List<NgControl>> errors =
        new Map<String, List<NgControl>>();
  
    final List<NgControl> _controls = new List<NgControl>();
  