return this.node.equals(((Pred<?>) that).node);
        } else {
          return false;
        }
      }

      @Override
      public int hashCode() {
        // Adding the class hashCode to avoid a clash with Succ instances.
        return Pred.class.hashCode() + node.hashCode();
      }
    }

    static final class Succ<N> extends NodeConnection<N> {
      Succ(N node) {
        super(node);
      }