anchor.diff:      }
     }
   
  +  /// Children input.
     List<VNode> get children => children_;
     set children(List<VNode> newChildren) {
       if (!identical(children_, newChildren)) {
  
positive.code:     }
    }
  
    void invalidated() {}
    void updated() {}
  
    void attached() {}
    void detached() {}
    void disposed() {}
  
    void dispose() {
  
negative.code:     _root = n;
    }
  
    /// invalidate
    void invalidate([_]) {
      if ((flags & dirtyFlag) == 0) {
        flags |= dirtyFlag;
  