Description:
------------
The closure is simply not rebound as described by the language specification using the bindTo function.

Test script:
---------------
<?php

class A {
    private $my_string;
    public function __construct($st) {
        $this->my_string = $st;
    }
    public function launch() {
        return function() {
            echo $this->my_string."\n";
        };
    }
}
$a = new A("go");
$fn = $a->launch();
$fn();
$a2 = new A("ppppp");
$fn->bindTo($a2);
$fn();

Expected result:
----------------
go
ppppp

Actual result:
--------------
go
go