hhvm/hphp/test/quick/zend_closure_005.php

<?php

class A {
	private $x;

	function __construct($x) {
		$this->x = $x;
	}

	function __destruct() {
		echo "Destroyed\n";
	}

	function getIncer($val) {
		return function() use ($val) {
			$this->x += $val;
		};
	}

	function getPrinter() {
		return function() {
			echo $this->x."\n";
		};
	}

	function printX() {
		echo $this->x."\n";
	}
}

$a = new A(3);
$incer = $a->getIncer(2);
$printer = $a->getPrinter();

$a->printX();
$printer();
$incer();
$a->printX();
$printer();

unset($a);

$incer();
$printer();

unset($incer);
$printer();

unset($printer);