Description:
------------
__invoke in child class not worked correctly?

Reproduce code:
---------------
class Callable
{
    function __invoke($x) {
        var_dump($x);
    }
}

class A {}

$obj = new Callable;

$a = new A;
$a->c = $obj;

var_dump(is_callable($obj));
var_dump(is_callable($a->c));

$obj(1);
$a->c(2);

Expected result:
----------------
bool(true)
bool(true)
int(1)
int(2)

Actual result:
--------------
bool(true)
bool(true)
int(1)

Fatal error: Call to undefined method A::c() in E:\Work\1.php on line 22
PHP Fatal error:  Call to undefined method A::c() in E:\Work\1.php on line 22