code: func (f *aclFilter) filterCheckServiceNodes(nodes *structs.CheckServiceNodes) {
  	csn := *nodes
  	for i := 0; i < len(csn); i++ {
  		node := csn[i]
  		if f.allowNode(node.Node.Node) && f.allowService(node.Service.Service) {
  			continue
  		}
  		f.logger.Printf("[DEBUG] consul: dropping node %q from result due to ACLs", node.Node.Node)
  		csn = append(csn[:i], csn[i+1:]...)
  		i--
  	}
  	*nodes = csn
  }
docs: // filterCheckServiceNodes is used to filter nodes based on ACL rules.