<?php
class XmlTest {
    function test_ref(&$test) {
        $test = "ok";
    }
    function test($test) { }
    function run() {
        $ar = array();
        $this->test_ref($ar[]);
        var_dump($ar);
        $this->test($ar[]);
    }
}
$o = new XmlTest();
$o->run();
?>
   This should always have thrown a fatal E_ERROR,
   because [] cannot be used for reading in PHP. It is invalid code in
   PHP 4.4.2 and PHP 5.0.5 upward.