Description:
------------
When a variable's type is "NULL" (as reported by var_dump()) which happens when the variable is set to 0, it can no longer be used to access the 0th position in an array.

In my perticular case, I was attempting this operation:
return $this->serverdata[$this->dataindex][$var];

and needed to do this to get it to run correctly:
return $this->serverdata[intval($this->dataindex)][$var];

I have not throughly tested this bug for other cases where it occurs, but this is definatly one of the cases.

Reproduce code:
---------------
class testing {
  private $dataindex;
  private $serverdata;

  function __construct() {
    $dataindex = 0;
    $serverdata = array(array("name"=>"Er1c","data"=>"foo"),array("name"=>"Bob","data"=>"bar"));
  }
  function __get($var) {
    return $this->serverdata[$this->dataindex][$var];
  }
}
$blah = new testing();
echo "Name:" . $blah->name;

Expected result:
----------------
Name: Er1c

Actual result:
--------------
Name: