code: @Override
    public void indexInsert(int index, KType key, VType value) {
      assert index < 0 : "The index must not point at an existing key.";
  
      index = ~index;
      if (Intrinsics.<KType> isEmpty(key)) {
        assert index == mask + 1;
        values[index] = value;
        hasEmptyKey = true;
      } else {
        assert Intrinsics.<KType> isEmpty(keys[index]);
  
        if (assigned == resizeAt) {
          allocateThenInsertThenRehash(index, key, value);
        } else {
          keys[index] = key;
          values[index] = value;
        }
  
        assigned++;
      }
    }
docs: {@inheritDoc}