*/
        V rightValue = uncheckedCastNullableTToT(onlyOnRight.remove(leftKey));
        if (valueEquivalence.equivalent(leftValue, rightValue)) {
          onBoth.put(leftKey, leftValue);
        } else {
          differences.put(leftKey, ValueDifferenceImpl.create(leftValue, rightValue));
        }
      } else {
        onlyOnLeft.put(leftKey, leftValue);
      }
    }
  }