static <A extends Concept> A nuLike shallowCloneToUnlistedConcept(Class<A> c, Concept o) {
  if (o == null) null;
  A cc = unlisted(c);
  ccopyFields(o, cc);
  ret cc;
}

static <A extends Concept> A shallowCloneToUnlistedConcept(A o) {
  ret o == null ? null : (A) shallowCloneToUnlistedConcept(o.getClass(), o);
}