Description:
------------
Assign return value of a function to a variable, inside another function expecting a reference. Triggers an E_STRICT error and other strange behavior.

Reproduce code:
---------------
<?php
$file = '/path/to/some/file.ext';
$extension = array_pop($fileParts = explode('.',basename($file)));


echo $extension."\n"; // This works, echoes 'ext'
echo count($fileParts); // Value is 2
?>

Expected result:
----------------
count($fileParts) should return 1, and E_STRICT errors shouldn't be triggered.

Actual result:
--------------
count($fileParts) returns 2, and an E_STRICT error is thrown