Hi Sebastian!
printLocalDate(time() + 60*60*24 * 12); // current time plus 12 days and myFunc($var = 'value'); is not much different, or?
Actually, this is much different. The first call doesn't need to to any variable assignment. The second call does, and needs to store it somewhere in memory.
Exactly this "store it in memory" has in the past time led to memory corruption, and was the reason why the PHP notice "Fatal error/Warning: Only variables can be passed by reference..." [1] was introduced, resulting in one really big BC break.
I think your method is a follow-up to that same problem, but it should also not have become changed without any notice in the ChangeLog. But it seems not many people use that mechanism, so it has/may not yet been reported. Which is all the more reason to post this report on bugs.php.net.
[1] http://cow.neondragon.net/index.php/375-Annoying-Things-About-Php http://phplens.com/phpeverywhere/?q=node/view/214
Regards, Garvin