Joomla gives error application\cms.php on line 471 what is it?

Question

Joomla

Warning: count(): Parameter must be an array or an object that implements Countable in A:\XAMP\htdocs\test\libraries\cms\application\cms.php on line 471

in line 471 - if (count($sessionQueue))
{
$this->_messageQueue = $sessionQueue;
$session->set('application.queue', null);
}

working on xampp