array_filter(): by-ref parameter in callback

Hi! There's a patch by Jesse Donat in PhDOE which suggest to add the following info to the array_filter() man page: | As of PHP7 the value of the callback may no longer be used by | reference. Actually, it seems that declaring the callback parameter by-ref is allowed (i.e. doesn't raise a notice or warning), but assignments to the parameter are silently ignored as of PHP 7.0.0, see <https://3v4l.org/T0fvi>. I have not been able to find any info about this in UPGRADING, so I wonder whether this behavioral change was intentional, and which other functions are affected as well.