case *ast.ForStmt:
		return 1 << nForStmt
	case *ast.FuncDecl:
		return 1 << nFuncDecl
	case *ast.FuncLit:
		return 1 << nFuncLit
	case *ast.FuncType:
		return 1 << nFuncType
	case *ast.GenDecl:
		return 1 << nGenDecl
	case *ast.GoStmt:
		return 1 << nGoStmt
	case *ast.Ident:
		return 1 << nIdent
	case *ast.IfStmt:
		return 1 << nIfStmt
	case *ast.ImportSpec:
		return 1 << nImportSpec

				log.Fatal("methods unsupported")
			}
			if decl.Body != nil {
				log.Fatal("unexpected function body")
			}
			fmt.Fprintf(w, "{%q, funcTag, %d},\n", decl.Name.Name, interner.intern(decl.Type))
		case *ast.GenDecl:
			if decl.Tok == token.IMPORT {
				if len(decl.Specs) != 1 || decl.Specs[0].(*ast.ImportSpec).Path.Value != "\"unsafe\"" {
					log.Fatal("runtime cannot import other package")
				}
				continue
			}

type Value struct {
	Doc   string
	Names []string // var or const names in declaration order
	Decl  *ast.GenDecl

	order int
}

// Type is the documentation for a type declaration.
type Type struct {
	Doc  string
	Name string
	Decl *ast.GenDecl

	// associated declarations
	Consts  []*Value // sorted list of constants of (mostly) this type

		}

	case *ast.FuncLit:
		// nop

	case *ast.FuncType:
		if n.Func != 0 {
			children = append(children,
				tok(n.Func, len("func")))
		}

	case *ast.GenDecl:
		children = append(children,
			tok(n.TokPos, len(n.Tok.String())))
		if n.Lparen != 0 {
			children = append(children,
				tok(n.Lparen, len("(")),
				tok(n.Rparen, len(")")))
		}

	// 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)
		}

// 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

	for _, s := range list {
		if r.filterSpec(s) {
			list[j] = s
			j++
		}
	}
	return list[0:j]
}

func (r *reader) filterDecl(decl ast.Decl) bool {
	switch d := decl.(type) {
	case *ast.GenDecl:
		d.Specs = r.filterSpecList(d.Specs, d.Tok)
		return len(d.Specs) > 0
	case *ast.FuncDecl:
		// ok to filter these methods early because any
		// conflicting method will be filtered here, too -