Description:
------------
<?php
  empty(' ');
?>

crashes without any message, despite E_ALL config. It crashes during parsing, this code doesn't have to be accessible.

empty() should get only variables as parameter, not values.

Reproduce code:
---------------
<?php
  empty(' ');
?>


Expected result:
----------------
Some error or warning telling empty() should get variable, not a value.

Actual result:
--------------
PHP crash without any message. Apache does not crash.