bug#10650: view-mode inconsistencies wrt special mode-class

[Glenn Morris]

Stefan Monnier wrote:

> The default global value of major-mode is not nil, so in 99% of the
> cases whether a mode is special will have zero effect. 

Yes, that's what I meant by saying that it doesn't seem a useful feature
to me.

> I really would be happy to declare that a nil default value for
> `major-mode' is not supported any more. So we can simply get rid of
> this "special mode-class" mess.

Fine by me, although the core functionality is already there of course
at very little cost.

> I'm not sure exactly what's the idea with view-mode's use of special
> mode class, but IIUC it's that we don't want to enable view-mode in
> major modes that already have view-mode-like keybindings, which might
> boil down to something along the lines of "major modes which use
> suppress-keymap".

Yes, and largely by coincidence IMO many of those modes happen to
have special mode-class.