anchor.diff:          return false; // never re-order these nodes
   
         ensureOldIdMap();
  -      oldNode = oldNodeIdMap[currentNode._key];
  +      oldNode = oldNodeIdMap[currentNode.key];
         if (oldNode == null)
           return false;
   
  -      oldNodeIdMap[currentNode._key] = null; // mark it reordered
  +      oldNodeIdMap[currentNode.key] = null; // mark it reordered
         assert(root is ContainerRenderObjectMixin);
         assert(old.root is ContainerRenderObjectMixin);
         assert(oldNode.root != null);
  
positive.code:     if (oldComponent == null || !oldComponent._stateful)
        return false;
  
      assert(key == oldComponent.key);
  
      // Make |this|, the newly-created object, into the "old" Component, and kill it
  
negative.code: 
  abstract class OneChildRenderObjectWrapper extends RenderObjectWrapper {
  
    OneChildRenderObjectWrapper({ String key, Widget child })
      : _child = child, super(key: key);
  
    Widget _child;
  