svoid test_replaceConceptAndUpdateRefs() {
  new Concepts cc;
  Concept a = cnew(cc, "A");
  Concept b = cnew(cc, "B");
  Concept a2 = unlisted("A");
  cset(b, +a);
  print(+a);
  print(+b);
  long id = a.id;
  replaceConceptAndUpdateRefs(a, a2);
  print(+a2);
  print(+b);
  assertSame(cc, a2.concepts());
  assertEquals(id, a2.id);
  assertEquals(allBackRefs(a2), ll(b));
}