public function testIndex()
{
$this->assertParsedAs(function () {
$i[0];
}, [O\Expression::index(O\Expression::variable(O\Expression::value('i')), O\Expression::value(0))]);
$this->assertParsedAs(function () {
//Must use write context
f($i[]);
}, [O\Expression::functionCall(O\Expression::value('f'), [O\Expression::argument(O\Expression::index(O\Expression::variable(O\Expression::value('i'))))])]);
}