php manual states
As of PHP 5.3.0, you will get a warning saying that "call-time pass-by-reference" is deprecated when you use & in foo(&$a);. And as of PHP 5.4.0, call-time pass-by-reference was removed, so using it will raise a fatal error.
why has the PHP team decided to do this? has there been any disadvantage by enabling pass by reference in previous releases? what factor has motivated for this decision?