Call to nonexistent function array_to_fields()

[Gold]

The function activity_get_users() in lib/activity.php includes a call to array_to_fields(). This function doesn't appear to have ever existed. Given we don't see any error reports on this it is likely the if() condition it falls into has never been triggered.

I am seeing activity_get_users() being called in htdocs/interaction/forum/lib.php in the constructor for the ActivityTypeInteractionForumPostmoderation class. This is also in an if() condition which suggests *that* is never hit either.

Given this has been present for the last 14 years I'm going to set the priority to low.