Description:
------------
If a class instance has a closure as property, PHP must call $this->closure->__invoke() instead of say that method class::closure() does not exist.

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

class foo
{
   protected $closure = null;

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

   function callClosure()
   {
      return $this->closure('Closure::__invoke() was called');
   }
}

$foo = new foo(function($string) { echo $string; });

$foo->callClosure();

?>

Expected result:
----------------
Closure::__invoke() was called

Actual result:
--------------
Call to undefined method foo::closure() in /path/to/script.php on line 14