The get_matches function returns an array, but as of very recently I'm unable to use it like an array.
Here are long-standing filters that now throw syntax errors:
- https://en.wikipedia.org/wiki/Special:AbuseFilter/926
- https://en.wikipedia.org/wiki/Special:AbuseFilter/944
- https://en.wikipedia.org/wiki/Special:AbuseFilter/955
Basically we're doing match := get_matches("regex", added_lines)[1].
get_matches can return false if there are no matches, in which case it's of course invalid to treat it like an array. But up until now I think AbuseFilter gracefully failed, which is more than fine in my case (since the filter would evaluate to false anyway).