// Copyright 2013 The Go Authors. All rights reserved.// Use of this source code is governed by a BSD-style// license that can be found in the LICENSE file.// +build OMITpackagemainimport"fmt"funcmain(){// START OMITtypeNodestruct{Next*NodeValueinterface{}}varfirst*Nodevisited:=make(map[*Node]bool)// HLforn:=first;n!=nil;n=n.Next{ifvisited[n]{// HLfmt.Println("cycle detected")break}visited[n]=true// HLfmt.Println(n.Value)}// END OMIT}