FlaggedRevs' checkbox label is displayed weirdly in VisualEditor save dialog.
FIXME this causes errors/notices. label-message can either be a string (message key) or a Message object. FlaggedRevs uses the latter, setting the label-message of one of its checkboxes to $this->msg( 'revreview-check-flag-p' )->numParams( $this->article->getPendingRevCount() );
Running something that's either a message key or a Message object through $this->msg() works just fine, but using it as an array index breaks: https://logstash.wikimedia.org/app/kibana#/doc/logstash-*/logstash-2017.09.14/mediawiki?id=AV6CDuKFePsvZ6LqgLXw&_g=h@44136fa . Even if it did automagically __toString() the Message object, that would have the wrong outcome, because we appear to want the message key as the index here, not the rendered message.
This FR checkbox is the only checkbox that uses a Message object, and I fear it might be completely broken by this change. But maybe magic __toString()-ification of the Message object both on this line and in the JSONification of $checkboxesDef makes it work by accident?