add(e);
        }
      } else {
        super.add(elements);
      }
      return this;
    }

    private void addDeduping(E element) {
      requireNonNull(hashTable); // safe because we check for null before calling this method
      int mask = hashTable.length - 1;
      int hash = element.hashCode();
      for (int i = Hashing.smear(hash); ; i++) {
        i &= mask;
        Object previous = hashTable[i];