sbool web_mergeNodesByFirstLabelIC_debug;

static void web_mergeNodesByFirstLabelIC(Web web) {
  web_check(web);
  Map<S, WebNode> index = caseInsensitiveMap();
  for (WebNode node : web.nodes)
    if (!(node instanceof WebRelation) && nempty(node.labels)) index.put(web.unparseLabel(first(node.labels)), node);
  
  for (WebNode node : cloneList(web.nodes)) if (!(node instanceof WebRelation) && nempty(node.labels)) {
    WebNode n = index.get(web.unparseLabel(first(node.labels)));
    if (n == node) continue;
    if (web_mergeNodesByFirstLabelIC_debug)
      print("Collapsing: " + node + " => " + n);
    web_collapseNodeTo(node, n);
  }
  web_check(web);
}