Description:
------------
When the name of a built in array is stored inside of an object attribute, its contents can't be access from the 'variable variable' without the use of eval.

So, print_r(${$this->array}) and print_r($$this->array) don't work, but eval("print_r(\${$this->array});") does.

When trying the same thing on a "regular" variable variable, it works as expected.

Reproduce code:
---------------
<?php
$built_in_array = '_SERVER';

class klass {

    function klass($array = '_SERVER') {
        $this->array = $array;
    }

    function printit() {
        print_r(${$this->array});
        #eval ("print_r(\${$this->array});");
    }
}   

print_r(${$built_in_array});

$k = new klass();
$k->printit();
?>

Expected result:
----------------
Array
(
    [HZ] => 100
    [TERM] => rxvt
    [SHELL] => /bin/bash
    [WINDOWID] => 31457282
...etc...

Array
(
    [HZ] => 100
    [TERM] => rxvt
    [SHELL] => /bin/bash
    [WINDOWID] => 31457282
...etc...

Actual result:
--------------
Array
(
    [HZ] => 100
    [TERM] => rxvt
    [SHELL] => /bin/bash
    [WINDOWID] => 31457282
...etc...