Description:
------------
I was working in VS.php with a CodeIgniter Project (5.2) and have not made any 
changes to the standard setup.

Test script:
---------------
<?php

$a = array(); 
$a["foo/bar"] = array();
$a["foo/bar"][] = "1";
$a["foo/bar"][] = "2";
$a["bar"] = "foo";

$b = http_build_query($a, NULL, "&");
// $b
// expected : foo%2Fbar%5B%5D=1&foo%2Fbar%5B%5D=2&bar=foo
// produced : foo%2Fbar%5B0%5D=1&foo%2Fbar%5B1%5D=2&bar=foo

$c = urldecode($b);
// $c
// expected : foo/bar[]=1&foo/bar[]=2&bar=foo
// produced : foo/bar[0]=1&foo/bar[1]=2&bar=foo

echo $c;

Expected result:
----------------
foo/bar[]=1&foo/bar[]=2&bar=foo

Actual result:
--------------
foo/bar[0]=1&foo/bar[1]=2&bar=foo