>> Here:
>>
>> /* Select for input extension events used by scroll bars.  This will
>>    result in the corresponding core events not being generated for
>>    SCROLL_BAR.  */
>>
>> MAYBE_UNUSED static void
>> xi_select_scroll_bar_events (struct x_display_info *dpyinfo,
>> 			     Window scroll_bar)
>>
>> "void" is fontified in the error face.
>
> I’ll try to come up with a heuristic.

Now, MAYBE_UNUSED is fontified as a type, and void as an identifier.  :(

>> #ifdef USE_GTK
>>       /* See comment in EnterNotify above */
>>       else if (dpyinfo->last_mouse_glyph_frame)
>>         x_note_mouse_movement (dpyinfo->last_mouse_glyph_frame,
>> 			       &event->xmotion, Qnil);
>> #endif
>>
>> "else" and "dpyinfo" are fontified as types.
>
> Same.

This seemed to work for a while, but it's broken again.