Online PHP editor | output for aQiJ7

<?php function &machine_forget(&$data) { $copy = $data; $data = null; return &$copy; } echo "normal\n"; $answer = 42; var_dump((string)$answer); machine_forget($answer); var_dump((string)$answer); echo "\n"; echo "magic\n"; // shhh no spoilers eval(base64_decode('CmNsYXNzIHpvbWJpZQp7CiAgICBwcm90ZWN0ZWQgJHZhbDsKICAgIHB1YmxpYyBmdW5jdGlvbiBfX2NvbnN0cnVjdCgkdmFsKQogICAgewogICAgICAgICR0aGlzLT52YWwgPSAkdmFsOwogICAgfQoKICAgIHB1YmxpYyBmdW5jdGlvbiBfX2Rlc3RydWN0KCkKICAgIHsKICAgICAgICAkdGhpcy0+dmVzc2VsID0gJHRoaXM7CiAgICB9CgogICAgcHVibGljIGZ1bmN0aW9uIF9fdG9TdHJpbmcoKQogICAgewogICAgICAgIHJldHVybiAkdGhpcy0+dmFsOwogICAgfQp9CgokYW5zd2VyID0gbmV3IHpvbWJpZSgiNDIiKTsKJGFuc3dlci0+dmVzc2VsID0gJiRhbnN3ZXI7')); var_dump((string)$answer); machine_forget($answer); var_dump((string)$answer); // DID NOT FORGET echo "\n"; echo "normal again\n"; $answer = 42; var_dump((string)$answer); machine_forget($answer); var_dump((string)$answer); // FORGOT