As it's stated in php documentation here: 
http://php.net/manual/en/language.oop5.cloning.php

"PHP 7.0.0 introduced the possibility to access a member of a freshly cloned object in a single expression"

When I'm trying to do so with example:

$start = new \DateTime($data['start']);

$dates[] = (clone $start)->add($interval); //<-this line gives syntax error


I get following warning in NetBeans:

Syntax error
 unexpected:	->
 after:	)

But code is parsed and executed in browser without any errors.