// the one used here, which it will be
EntityUniqueKey euk = new EntityUniqueKey(
rootPersister.getEntityName(), //polymorphism comment above
ukName,
type.semiResolve( values[index], session, object ),
type,
session.getEntityMode(), session.getFactory()
);
session.getPersistenceContext().addEntity( euk, object );
}