Description:
------------
When a property is used as a reference by e.g. using array_pop on it, its is_ref flag is persisted, which turns the property into a reference, and breaks get_object_vars for example. See example script

See also https://3v4l.org/dcPn6

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

class foo
{
    protected $bar = array('baz');

    function bar()
    {
        array_pop($this->bar);
        $vars = get_object_vars($this);
        print_r($vars);
        $this->bar[] = array('buz');
        print_r($vars);
    }
}

$f = new foo();
$f->bar();


Expected result:
----------------
Array
(
    [bar] => Array
        (
        )

)
Array
(
    [bar] => Array
        (
        )

)


Actual result:
--------------
Array
(
    [bar] => Array
        (
        )

)
Array
(
    [bar] => Array
        (
            [0] => Array
                (
                    [0] => buz
                )

        )

)