Description:
------------
When passing a non-existing portion of an array by reference this portion gets created even if the function does not touch the array => it is modified in the calling line.

It works with string indexes as well.

Reproduce code:
---------------
error_reporting(E_ALL);

$tab2 = array( );

function do_nothing ( &$var ) { 
// code here doesnt matter
}

do_nothing($tab2[10]);
var_dump($tab2);



Expected result:
----------------
array(0) {
}


Actual result:
--------------
array(1) {
  [10]=>
  NULL
}