Online PHP editor | refs for Y269Z

<?php error_reporting(-1); $null = null; $arr = array(); $str = 'string'; $int = 7; $dbl = 7.3; $bool = true; $obj = new stdClass(); echo $null['nope']; echo $null['nope']['sure']; echo $null['nope'][] = 'wat!?!'; echo $arr['nope']; echo $arr['nope']['sure']; echo $arr['nope'][] = 'wat!?!'; echo $str['nope']; echo $str['nope']['sure']; echo $str['nope'][] = 'wat!?!'; echo $int['nope']; echo $int['nope']['sure']; echo $int['nope'][] = 'wat!?!'; echo $dbl['nope']; echo $dbl['nope']['sure']; echo $dbl['nope'][] = 'wat!?!'; echo $bool['nope']; echo $bool['nope']['sure']; echo $bool['nope'][] = 'wat!?!'; echo $obj['nope']; echo $obj['nope']['sure']; echo $obj['nope'][] = 'wat!?!';