const src = `// comment 1
	// comment 2
	// comment 3
	package main
	`

	fset := token.NewFileSet()
	f, err := parser.ParseFile(fset, "", src, parser.ParseComments)
	if err != nil {
		panic(err) // error in test
	}

	var buf bytes.Buffer
	fset = token.NewFileSet() // use the wrong file set
	Fprint(&buf, fset, f)

	nlines := 0
	for _, ch := range buf.Bytes() {
		if ch == '\n' {
			nlines++

func TestFileSetPastEnd(t *testing.T) {
	fset := NewFileSet()
	for _, test := range tests {
		fset.AddFile(test.filename, fset.Base(), test.size)
	}
	if f := fset.File(Pos(fset.Base())); f != nil {
		t.Errorf("got %v, want nil", f)
	}
}

func TestFileSetCacheUnlikely(t *testing.T) {
	fset := NewFileSet()
	offsets := make(map[string]int)
	for _, test := range tests {

		if tokenclass(got) == literal && lit == "" {
			t.Errorf("%s: for %s got empty literal string", fset.Position(pos), got)
		}
	}
}

func BenchmarkScan(b *testing.B) {
	b.StopTimer()
	fset := token.NewFileSet()
	file := fset.AddFile("", fset.Base(), len(source))
	var s Scanner
	b.StartTimer()
	for i := 0; i < b.N; i++ {
		s.Init(file, source, nil, ScanComments)
		for {
			_, tok, _ := s.Scan()

// and calls os.Exit with an appropriate error code.
// It assumes flags have already been set.
func Run(configFile string, analyzers []*analysis.Analyzer) {
	cfg, err := readConfig(configFile)
	if err != nil {
		log.Fatal(err)
	}

	fset := token.NewFileSet()
	results, err := run(fset, cfg, analyzers)
	if err != nil {
		log.Fatal(err)
	}

//+build tag

// Package p doc comment.
package p

var lastDecl int

/* end of file */
`
	fset := token.NewFileSet()
	f, err := ParseFile(fset, "file.go", src, 0)
	if err != nil {
		t.Fatal(err)
	}

	// File{Start,End} spans the entire file, not just the declarations.
	if got, want := fset.Position(f.FileStart).String(), "file.go:1:1"; got != want {
		t.Errorf("for File.FileStart, got %s, want %s", got, want)

	}

	imports := make(map[string]*types.Package)
	fset := token.NewFileSet()
	_, err := Import(fset, imports, "net/http", ".", nil)
	if err != nil {
		t.Fatal(err)
	}

	mutex := imports["sync"].Scope().Lookup("Mutex").(*types.TypeName).Type()
	mset := types.NewMethodSet(types.NewPointer(mutex)) // methods of *sync.Mutex
	sel := mset.Lookup(nil, "Lock")
	lock := sel.Obj().(*types.Func)

		return nil, nil // doesn't use cgo
	}

	cgofiles, info, err := typeCheckCgoSourceFiles(pass.Fset, pass.Pkg, pass.Files, pass.TypesInfo, pass.TypesSizes)
	if err != nil {
		return nil, err
	}
	for _, f := range cgofiles {
		checkCgo(pass.Fset, f, info, pass.Reportf)
	}
	return nil, nil
}

func checkCgo(fset *token.FileSet, f *ast.File, info *types.Info, reportf func(token.Pos, string, ...interface{})) {

// with context specified by the -c flag.
func PrintPlain(fset *token.FileSet, diag analysis.Diagnostic) {
	posn := fset.Position(diag.Pos)
	fmt.Fprintf(os.Stderr, "%s: %s\n", posn, diag.Message)

	// -c=N: show offending line plus N lines of context.
	if Context >= 0 {
		posn := fset.Position(diag.Pos)
		end := fset.Position(diag.End)
		if !end.IsValid() {
			end = posn
		}

	if err != nil {
		return ""
	}
	defer f.Close()

	var src [4 << 10]byte // read at most 4KB
	n, _ := f.Read(src[:])

	var first string
	var s scanner.Scanner
	s.Init(fset.AddFile("", fset.Base(), n), src[:n], nil /* ignore errors */, scanner.ScanComments)
	for {
		_, tok, lit := s.Scan()
		switch tok {
		case token.COMMENT:
			// remove trailing */ of multi-line comment
			if lit[1] == '*' {

.*have M5[(]struct{b[.]S; b[.]t}[)]
.*want M5[(]struct{b[.]S; t}[)]`},
	}

	fset := token.NewFileSet()
	test := func(main, b, want string) {
		re := regexp.MustCompile(want)
		bpkg := mustTypecheck(b, nil, nil)
		mast := mustParse(fset, main)
		conf := Config{Importer: importHelper{pkg: bpkg}}
		_, err := conf.Check(mast.Name.Name, fset, []*ast.File{mast}, nil)
		if err == nil {
			t.Error("Expected failure, but it did not")