Comment 39 for bug 1505409

Just for the sake of adding a comment too... I am getting this in the following situation. I hope the description is correct.
 1) I change the display set-up on my laptop slightly too fast, e.g. close the lid, re-open, re-close (I did that quite a bit recently trying to work out bug patterns).
 2) GNOME Shell creates a wl_output object for the internal screen, reports it to Xwayland, then removes it again because the screen is disabled again.
 3) Xwayland asks GNOME Shell for more information about the no-longer-existing wl_output object and GNOME Shell (in the Wayland library code) terminates the connection because it considers asking about a non-existing object to be a bug.
 4) Xwayland dutifully terminates and GNOME Shell panics and terminates too.

See: https://phabricator.freedesktop.org/T7722