for _, d := range depDecls {
		switch d := d.(type) {
		case *ast.GenDecl:
			if d.Doc != nil {
				comments = append(comments, d.Doc)
			}
		case *ast.FuncDecl:
			if d.Doc != nil {
				comments = append(comments, d.Doc)
			}
		}
	}

	// Synthesize import declaration.
	importDecl := &ast.GenDecl{
		Tok:    token.IMPORT,
		Lparen: 1, // Need non-zero Lparen and Rparen so that printer

	case nil:
		return ""

	case *ast.GenDecl:
		// Formats const and var declarations.
		trailer := ""
		if len(n.Specs) > 1 {
			trailer = " " + dotDotDot
		}

		// Find the first relevant spec.
		typ := ""
		for i, spec := range n.Specs {
			valueSpec := spec.(*ast.ValueSpec) // Must succeed; we can't mix types in one GenDecl.

	nodeFilter := []ast.Node{
		(*ast.AssignStmt)(nil),
		(*ast.CallExpr)(nil),
		(*ast.CompositeLit)(nil),
		(*ast.FuncDecl)(nil),
		(*ast.FuncLit)(nil),
		(*ast.GenDecl)(nil),
		(*ast.RangeStmt)(nil),
		(*ast.ReturnStmt)(nil),
	}
	inspect.Preorder(nodeFilter, func(node ast.Node) {
		switch node := node.(type) {
		case *ast.RangeStmt:
			checkCopyLocksRange(pass, node)

// predeclared) type. The namedType for a type name is always found via
// reader.lookupType.
type namedType struct {
	doc  string       // doc comment for type
	name string       // type name
	decl *ast.GenDecl // nil if declaration hasn't been seen yet

	isEmbedded bool        // true if this type is embedded
	isStruct   bool        // true if this type is a struct
	embedded   embeddedSet // true if the embedded type is a pointer

	}
)

// Pos and End implementations for declaration nodes.

func (d *BadDecl) Pos() token.Pos  { return d.From }
func (d *GenDecl) Pos() token.Pos  { return d.TokPos }
func (d *FuncDecl) Pos() token.Pos { return d.Type.Pos() }

func (d *BadDecl) End() token.Pos { return d.To }
func (d *GenDecl) End() token.Pos {
	if d.Rparen.IsValid() {
		return d.Rparen + 1
	}
	return d.Specs[0].End()
}

	// except in the definition (handled at end of function).
	refName := make(map[*ast.Expr]*Name)
	for _, r := range f.Ref {
		refName[r.Expr] = r.Name
	}
	for _, d := range f.AST.Decls {
		d, ok := d.(*ast.GenDecl)
		if !ok || d.Tok != token.TYPE {
			continue
		}
		for _, s := range d.Specs {
			s := s.(*ast.TypeSpec)
			n := refName[&s.Type]
			if n != nil && n.Mangle != "" {
				override[n.Mangle] = s.Name.Name
			}

	// and AST nodes.
	cmap := ast.NewCommentMap(fset, f, f.Comments)

	// Remove the first variable declaration from the list of declarations.
	for i, decl := range f.Decls {
		if gen, ok := decl.(*ast.GenDecl); ok && gen.Tok == token.VAR {
			copy(f.Decls[i:], f.Decls[i+1:])
			f.Decls = f.Decls[:len(f.Decls)-1]
			break
		}
	}

	// Use the comment map to filter comments that don't belong anymore

	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)
		}