Description:
------------
Where you can do ${'var'} with a normal variable trying to 
do the same thing with a class prop. results in a fatal 
error. It happens inside{$this} and outside the class. 
With public, private, and protected. It does work 
correctly with static variables. 

Reproduce code:
---------------
<?php

class Test
{
  protected $variable = 'one';

  public function test(){
    print $this->variable;
    print $this->${'variable'};
  }

}
$t = new Test;

?>

Expected result:
----------------
oneone 

Actual result:
--------------
one 
 Fatal error: Cannot access empty property 
in /www/unstable/apache2/php5/admin/mRio/mRioDUM/bella1/test.php 
on line 9