- var_dump: documentation ( source)
<?php
$file_link = array(
'#theme' => 'file_link',
'#file' => 'blah.html',
);
$element = $file_link =+ array('#weight' => -10);
var_dump($element);
//$element['file'] = $file_link += array('#weight' => -10);
var_dump($element);