protected override QilNode VisitPositionOf(QilUnary ndPos) {
QilIterator ndIter = ndPos.Child as QilIterator;
LocalBuilder locPos;
Debug.Assert(ndIter.NodeType == QilNodeType.For);
locPos = XmlILAnnotation.Write(ndIter).CachedIteratorDescriptor.LocalPosition;
Debug.Assert(locPos != null);
this.iterCurr.Storage = StorageDescriptor.Local(locPos, typeof(int), false);
return ndPos;
}