Description:
------------
Memory Leak in classes cycle reference

Test script:
---------------
class foo  {
	protected $mBar=null;
	
	public function setBar(bar $value){
		$this->mBar=$value;
	}
	
	public function __destruct(){
 		unset($this->mBar);	 	
 	}
}


class bar  {
	protected $mFoo=null;
	protected $mContent=null;
	
	public function __construct() {
		$this->mContent=str_repeat("prova",10000);
	}
	
	public function setFoo(foo $value){
		$this->mFoo=$value;
	}
	public function __destruct(){
 		unset($this->mFoo);	 	
 	}
}



ini_set("memory_limit","32M");		
		
$cont=0;
		
while($cont<1000){
	$cont++;
	$tmp_foo=new Foo();
	$tmp_bar= new Bar();
	
	$tmp_foo->setBar($tmp_bar);
	$tmp_bar->setFoo($tmp_foo);
	unset($tmp_foo, $tmp_bar);				
}

Expected result:
----------------
no mem leak

Actual result:
--------------
Fatal error: Allowed memory size of 33554432 bytes exhausted (tried to allocate 50001 bytes)