for (K type : types) {
        collectTypes(type, map);
      }
      return sortKeysByValue(map, Ordering.natural().reverse());
    }

    /** Collects all types to map, and returns the total depth from T up to Object. */
    @CanIgnoreReturnValue
    private int collectTypes(K type, Map<? super K, Integer> map) {
      Integer existing = map.get(type);
      if (existing != null) {