--edgeCount;
      }
    }

    for (N successor : ImmutableList.copyOf(connections.successors())) {
      // requireNonNull is safe because the node is a successor.
      requireNonNull(nodeConnections.getWithoutCaching(successor)).removePredecessor(node);
      requireNonNull(connections.removeSuccessor(successor));
      --edgeCount;
    }
    if (isDirected()) { // In undirected graphs, the successor and predecessor sets are equal.