anchor.diff:    void scheduleBuildFor(BuildableElement element) {
       assert(element != null);
       assert(element.owner == this);
  -    assert(element._inDirtyList == _dirtyElements.contains(element));
       assert(() {
         if (debugPrintScheduleBuildForStacks)
           debugPrintStack(label: 'scheduleBuildFor() called for $element${_dirtyElements.contains(element) ? " (ALREADY IN LIST)" : ""}');
  
positive.code: 
    @override
    void _reassemble() {
      assert(_active); // otherwise markNeedsBuild is a no-op
      markNeedsBuild();
      super._reassemble();
    }
  
negative.code:   /// This function is called only during the "active" lifecycle state.
    @mustCallSuper
    void update(@checked Widget newWidget) {
      // This code is hot when hot reloading, so we try to
      // only call _AssertionError._evaluateAssertion once.
      assert(_debugLifecycleState == _ElementLifecycle.active
          && widget != null
          && newWidget != null
          && newWidget != widget
          && depth != null
          && _active
          && Widget.canUpdate(widget, newWidget));
      _widget = newWidget;
    }
  
  