func getFile(fset *token.FileSet, filename string) (file *token.File) {
	fset.Iterate(func(f *token.File) bool {
		if f.Name() == filename {
			if file != nil {
				panic(filename + " used multiple times")
			}
			file = f
		}
		return true
	})
	return file
}

func getPos(fset *token.FileSet, filename string, offset int) token.Pos {
	if f := getFile(fset, filename); f != nil {
		return f.Pos(offset)

// struct fields are never printed.
func Fprint(w io.Writer, fset *token.FileSet, x any, f FieldFilter) error {
	return fprint(w, fset, x, f)
}

func fprint(w io.Writer, fset *token.FileSet, x any, f FieldFilter) (err error) {
	// setup printer
	p := printer{
		output: w,
		fset:   fset,
		filter: f,
		ptrmap: make(map[any]int),
		last:   '\n', // force printing of line number on first line

{{range .}}	{{synopsis .Doc}}
	{{node .Decl $.FSet}}

{{end}}{{end}}{{/*

*/}}{{with .Vars}}
VARIABLES
{{range .}}	{{synopsis .Doc}}
	{{node .Decl $.FSet}}

{{end}}{{end}}{{/*

*/}}{{with .Funcs}}
FUNCTIONS
{{range .}}	{{synopsis .Doc}}
	{{node .Decl $.FSet}}

{{end}}{{end}}{{/*

*/}}{{with .Types}}
TYPES
{{range .}}	{{synopsis .Doc}}
	{{node .Decl $.FSet}}

{{range .Consts}}	{{synopsis .Doc}}

func ExampleGreet_world() {
	Greet("world")
}
`

	// Create the AST by parsing src and test.
	fset := token.NewFileSet()
	files := []*ast.File{
		mustParse(fset, "src.go", src),
		mustParse(fset, "src_test.go", test),
	}

	// Compute package documentation with examples.
	p, err := doc.NewFromFiles(fset, files, "example.com/p")
	if err != nil {
		panic(err)
	}

	pkg, err := conf.Check("temperature", fset, []*ast.File{f}, nil)
	if err != nil {
		log.Fatal(err)
	}

	// Print the method sets of Celsius and *Celsius.
	celsius := pkg.Scope().Lookup("Celsius").Type()
	for _, t := range []types.Type{celsius, types.NewPointer(celsius)} {
		fmt.Printf("Method set of %s:\n", t)
		mset := types.NewMethodSet(t)
		for i := 0; i < mset.Len(); i++ {
			fmt.Println(mset.At(i))
		}

	conf := types.Config{Importer: importer.Default()}
	_, err = conf.Check("runtime", fset, files, &info)
	if err != nil {
		t.Fatalf("typechecking runtime failed: %v", err)
	}

	// Analyze all atomic.*64 callsites.
	v := Visitor{t: t, fset: fset, types: info.Types, checked: checked}
	ast.Walk(&v, pkg)
}

type Visitor struct {
	fset    *token.FileSet
	types   map[ast.Expr]types.TypeAndValue
	checked map[string]bool

	testenv.MustHaveGoBuild(t) // The Go command is needed for the importer to determine the locations of stdlib .a files.

	fset := token.NewFileSet()
	files, err := pkgFiles(fset, ".")
	if err != nil {
		t.Fatal(err)
	}

	conf := Config{Importer: importer.Default()}
	_, err = conf.Check("go/types", fset, files, nil)
	if err != nil {
		t.Fatal(err)
	}
}

func BenchmarkCheck(b *testing.B) {

		t.Error(pvagenfile + " is out of date")
	}

}

func pvagenerate(t *testing.T) string {
	var fset token.FileSet
	f, err := parser.ParseFile(&fset, "./dwarf.go", nil, parser.ParseComments)
	if err != nil {
		t.Fatal(err)
	}
	cm := ast.NewCommentMap(&fset, f, f.Comments)
	abbrevs := make(map[string]int)
	funcs := map[string]ast.Stmt{}
	for _, decl := range f.Decls {

			lastSpec := d.Specs[len(d.Specs)-1]
			lastLine := lineAt(fset, lastSpec.Pos())
			rParenLine := lineAt(fset, d.Rparen)
			for rParenLine > lastLine+1 {
				rParenLine--
				fset.File(d.Rparen).MergeLine(rParenLine)
			}
		}
	}
}

func lineAt(fset *token.FileSet, pos token.Pos) int {
	return fset.PositionFor(pos, false).Line
}

func importPath(s Spec) string {

	nfiles  int // number of files processed
)

func gofmt(fset *token.FileSet, filename string, src *bytes.Buffer) error {
	f, _, _, err := parse(fset, filename, src.Bytes(), false)
	if err != nil {
		return err
	}
	ast.SortImports(fset, f)
	src.Reset()
	return (&printer.Config{Mode: printerMode, Tabwidth: tabWidth}).Fprint(src, fset, f)
}

func testFile(t *testing.T, b1, b2 *bytes.Buffer, filename string) {