case _Lparen:
		p.next()
		t := p.type_()
		p.want(_Rparen)
		return t
	}

	return nil
}

func (p *parser) typeInstance(typ Expr) Expr {
	if trace {
		defer p.trace("typeInstance")()
	}

	pos := p.pos()
	p.want(_Lbrack)
	x := new(IndexExpr)
	x.pos = pos
	x.X = typ
	if p.tok == _Rbrack {

	value := p.parseType()

	return &ast.ChanType{Begin: pos, Arrow: arrow, Dir: dir, Value: value}
}

func (p *parser) parseTypeInstance(typ ast.Expr) ast.Expr {
	if p.trace {
		defer un(trace(p, "TypeInstance"))
	}

	opening := p.expect(token.LBRACK)
	p.exprLev++
	var list []ast.Expr
	for p.tok != token.RBRACK && p.tok != token.EOF {
		list = append(list, p.parseType())