Description:
------------
I have a class that have a constructor function, you can study the code, the result of execute the script is diferent for the  expect

Reproduce code:
---------------
<?php
class usuario 
{
	var $nombre;
	var $edad;
	var $cargo;

	function set_name($name)
	{
		$this->$nombre=$name;
	}
	function usuario()
	{
		$this->$nombre="(Undefined)";
		$this->$edad=0;
		$this->$cargo="(not a charge)";
	}
}

$daniel = new usuario;
$daniel->set_name("daniel");
echo $daniel->$nombre;
echo '<br>';
echo $daniel->$edad;
echo '<br>';
echo $daniel->$cargo;
?>

Expected result:
----------------
daniel
0
(not a charge)

Actual result:
--------------
daniel
daniel
daniel