if err != nil {
		t.Fatal(err)
	}

	// RHS refers to undefined globals; LHS does not.
	as := f.Decls[0].(*ast.FuncDecl).Body.List[0].(*ast.DeclStmt).Decl.(*ast.GenDecl).Specs[0].(*ast.ValueSpec)
	for _, v := range as.Values {
		id := v.(*ast.Ident)
		if id.Obj != nil {
			t.Errorf("rhs %s has Obj, should not", id.Name)
		}
	}
	for _, id := range as.Names {

	}

	var stmtBranches func(ast.Stmt)
	stmtBranches = func(s ast.Stmt) {
		switch s := s.(type) {
		case *ast.DeclStmt:
			if d, _ := s.Decl.(*ast.GenDecl); d != nil && d.Tok == token.VAR {
				recordVarDecl(d.Pos())
			}

		case *ast.LabeledStmt:
			// declare non-blank label
			if name := s.Label.Name; name != "_" {

		Walk(v, n.Name)
		if n.TypeParams != nil {
			Walk(v, n.TypeParams)
		}
		Walk(v, n.Type)
		if n.Comment != nil {
			Walk(v, n.Comment)
		}

	case *BadDecl:
		// nothing to do

	case *GenDecl:
		if n.Doc != nil {
			Walk(v, n.Doc)
		}
		walkList(v, n.Specs)

	case *FuncDecl:
		if n.Doc != nil {
			Walk(v, n.Doc)
		}
		if n.Recv != nil {
			Walk(v, n.Recv)
		}

// It also removes duplicate imports when it is possible to do so without data loss.
func SortImports(fset *token.FileSet, f *File) {
	for _, d := range f.Decls {
		d, ok := d.(*GenDecl)
		if !ok || d.Tok != token.IMPORT {
			// Not an import declaration, so we're done.
			// Imports are always first.
			break
		}

		if !d.Lparen.IsValid() {
			// Not a block: sorted by default.
			continue

	err = Fprint(&buf, fset, f)
	if err != nil {
		t.Fatal(err)
	}
	original := buf.String()

	// now remove parentheses from the declaration
	for i := 0; i != len(f.Decls); i++ {
		f.Decls[i].(*ast.GenDecl).Lparen = token.NoPos
	}
	buf.Reset()
	err = Fprint(&buf, fset, f)
	if err != nil {
		t.Fatal(err)
	}
	noparen := buf.String()

	if noparen != original {

			// Calls to panic, os.Exit, etc, never return.
			b.current = b.newBlock(KindUnreachable, s)
		}

	case *ast.DeclStmt:
		// Treat each var ValueSpec as a separate statement.
		d := s.Decl.(*ast.GenDecl)
		if d.Tok == token.VAR {
			for _, spec := range d.Specs {
				if spec, ok := spec.(*ast.ValueSpec); ok {
					b.add(spec)
				}
			}
		}

	case *ast.LabeledStmt:
		label = b.labeledBlock(s.Label, s)

		p.print("BadDecl")
	case *ast.GenDecl:
		p.genDecl(d)
	case *ast.FuncDecl:
		p.funcDecl(d)
	default:
		panic("unreachable")
	}
}

// ----------------------------------------------------------------------------
// Files

func declToken(decl ast.Decl) (tok token.Token) {
	tok = token.ILLEGAL
	switch d := decl.(type) {
	case *ast.GenDecl:
		tok = d.Tok
	case *ast.FuncDecl:

	if info.parseErr != nil {
		return nil
	}

	hasEmbed := false
	for _, decl := range info.parsed.Decls {
		d, ok := decl.(*ast.GenDecl)
		if !ok {
			continue
		}
		for _, dspec := range d.Specs {
			spec, ok := dspec.(*ast.ImportSpec)
			if !ok {
				continue
			}
			quoted := spec.Path.Value

			a.apply(n, "TypeParams", nil, tparams)
		}
		a.apply(n, "Type", nil, n.Type)
		a.apply(n, "Comment", nil, n.Comment)

	case *ast.BadDecl:
		// nothing to do

	case *ast.GenDecl:
		a.apply(n, "Doc", nil, n.Doc)
		a.applyList(n, "Specs")

	case *ast.FuncDecl:
		a.apply(n, "Doc", nil, n.Doc)
		a.apply(n, "Recv", nil, n.Recv)
		a.apply(n, "Name", nil, n.Name)

	p.declare(spec, p.topScope, ast.Var, idents...)

	return spec
}

func (p *parser) parseGenDecl(keyword token.Token, f parseSpecFunction) *ast.GenDecl {
	if p.trace {
		defer un(trace(p, "GenDecl("+keyword.String()+")"))
	}

	doc := p.leadComment
	pos := p.expect(keyword)
	var lparen, rparen token.Pos
	var list []ast.Spec
	if p.tok == token.LPAREN {