docs: function PropertyReference(parentReference, propertyKey) {
        _classCallCheck(this, PropertyReference);
  
        _CachedReference.call(this);
  
        var parentReferenceTag = parentReference.tag;
        var parentObjectTag = new _glimmerReference.UpdatableTag(_glimmerReference.CURRENT_TAG);
  
        this.tag = _glimmerReference.combine([parentReferenceTag, parentObjectTag]);
        this._parentReference = parentReference;
        this._parentObjectTag = parentObjectTag;
        this._propertyKey = propertyKey;
      }