is_comments_popup error

Using WordPress v4.5 you get an is_comments_popup() error because that function is deprecated in v4.5 (or at least the current beta).

You can bypass the problem prior to a fix from the plugin using a hook as you can see in this pull request:

https://github.com/mikeschinkel/query-monitor/commit/9fb5cc10926d5bbe1730c184a9af7990ab687398

Hope this helps someone.

https://wordpress.org/plugins/query-monitor/