Description:
------------
It occurs in all current versions
Incoming request data are malformed:


        POST / HTTP/1.1
        Host: localhost
        Content-Type: application/x-www-form-urlencoded
        Content-Length: 17

        a%5Bb%5Bc%5D%5D=d


Reproduce code:
---------------
<form action="s.php" method="post">
        <p>
                <input name="a[b[c]]" type="text"/>
                <input type="submit">
        </p>
</form>
#####################################################
<?php
# s.php
$a=array('a'=>array('b[c]'=>'d'));
print_r($_POST);
print_r($a);
?>

Expected result:
----------------
Array
(
    [a] => Array
        (
            [b[c]] => d
        )

)
Array
(
    [a] => Array
        (
            [b[c]] => d
        )

)

Actual result:
--------------
Array
(
    [a] => Array
        (
            [b[c] => d
        )

)
Array
(
    [a] => Array
        (
            [b[c]] => d
        )

)

So, I miss "]" in POST data.