// If no deserializer, use the base DeserializerImpl.
// There may not be enough information yet to choose the
// specific deserializer.
if (dSer == null) {
dSer = new DeserializerImpl();
// determine a default type for this child element
TypeMapping tm = context.getTypeMapping();
Class type = propDesc.getType();
dSer.setDefaultType(tm.getTypeQName(type));
}