tok(n.Ellipsis, len("...")))

	case *ast.EmptyStmt:
		// nop

	case *ast.ExprStmt:
		// nop

	case *ast.Field:
		// TODO(adonovan): Field.{Doc,Comment,Tag}?

	case *ast.FieldList:
		children = append(children,
			tok(n.Opening, len("(")), // or len("[")
			tok(n.Closing, len(")"))) // or len("]")

	case *ast.File:
		// TODO test: Doc
		children = append(children,

	if p.trace {
		defer un(trace(p, "Result"))
	}

	if p.tok == token.LPAREN {
		return p.parseParameters(scope, false)
	}

	typ := p.tryType()
	if typ != nil {
		list := make([]*ast.Field, 1)
		list[0] = &ast.Field{Type: typ}
		return &ast.FieldList{List: list}
	}

	return nil
}

func (p *parser) parseSignature(scope *ast.Scope) (params, results *ast.FieldList) {
	if p.trace {

		typ.Methods = trimUnexportedFields(typ.Methods, true)
	}
}

// trimUnexportedFields returns the field list trimmed of unexported fields.
func trimUnexportedFields(fields *ast.FieldList, isInterface bool) *ast.FieldList {
	what := "methods"
	if !isInterface {
		what = "fields"
	}

	trimmed := false
	list := make([]*ast.Field, 0, len(fields.List))
	for _, field := range fields.List {

	case *StructType:
		p.print(_Struct)
		if len(n.FieldList) > 0 && p.linebreaks {
			p.print(blank)
		}
		p.print(_Lbrace)
		if len(n.FieldList) > 0 {
			if p.linebreaks {
				p.print(newline, indent)
				p.printFieldList(n.FieldList, n.TagList, _Semi)
				p.print(outdent, newline)
			} else {
				p.printFieldList(n.FieldList, n.TagList, _Semi)
			}
		}
		p.print(_Rbrace)

			if r == nil {
				return nil
			}
			returns = append(returns, &ast.Field{
				Type: r,
			})
		}
		return &ast.FuncType{
			Params: &ast.FieldList{
				List: params,
			},
			Results: &ast.FieldList{
				List: returns,
			},
		}
	case interface{ Obj() *types.TypeName }: // *types.{Alias,Named,TypeParam}
		if t.Obj().Pkg() == nil {
			return ast.NewIdent(t.Obj().Name())

	case *ast.Ellipsis:
		return 1 << nEllipsis
	case *ast.EmptyStmt:
		return 1 << nEmptyStmt
	case *ast.ExprStmt:
		return 1 << nExprStmt
	case *ast.Field:
		return 1 << nField
	case *ast.FieldList:
		return 1 << nFieldList
	case *ast.File:
		return 1 << nFile
	case *ast.ForStmt:
		return 1 << nForStmt
	case *ast.FuncDecl:
		return 1 << nFuncDecl
	case *ast.FuncLit:
		return 1 << nFuncLit

pkg go/ast, type FuncType struct, TypeParams *FieldList
pkg go/ast, type IndexListExpr struct
pkg go/ast, type IndexListExpr struct, Indices []Expr
pkg go/ast, type IndexListExpr struct, Lbrack token.Pos
pkg go/ast, type IndexListExpr struct, Rbrack token.Pos
pkg go/ast, type IndexListExpr struct, X Expr
pkg go/ast, type TypeSpec struct, TypeParams *FieldList
pkg go/constant, method (Kind) String() string

// ----------------------------------------------------------------------------
// Implementation

// funcType type-checks a function or method type.
func (check *Checker) funcType(sig *Signature, recvPar *ast.FieldList, ftyp *ast.FuncType) {
	check.openScope(ftyp, "function")
	check.scope.isFunc = true
	check.recordScope(ftyp, check.scope)
	sig.scope = check.scope
	defer check.closeScope()

	//     14  .  .  .  .  .  Decl: *(obj @ 7)
	//     15  .  .  .  .  }
	//     16  .  .  .  }
	//     17  .  .  .  Type: *ast.FuncType {
	//     18  .  .  .  .  Func: 3:1
	//     19  .  .  .  .  Params: *ast.FieldList {
	//     20  .  .  .  .  .  Opening: 3:10
	//     21  .  .  .  .  .  Closing: 3:11
	//     22  .  .  .  .  }
	//     23  .  .  .  }
	//     24  .  .  .  Body: *ast.BlockStmt {
	//     25  .  .  .  .  Lbrace: 3:13

		return fmt.Sprintf("types.NewStruct(%s)", i.fields(t.Fields, true))

	default:
		log.Fatalf("unhandled type: %#v", t)
		panic("unreachable")
	}
}

func (i *typeInterner) fields(fl *ast.FieldList, keepNames bool) string {
	if fl == nil || len(fl.List) == 0 {
		return "nil"
	}

	var res []string
	for _, f := range fl.List {
		typ := i.subtype(f.Type)
		if len(f.Names) == 0 {