bug#24706: 26.0.50; Minor mode functions should do strict argument type checking

[Eli Zaretskii]

> From: Philipp Stephani <p.stephani2@gmail.com>
> Date: Sun, 16 Oct 2016 18:13:01 +0000
> 
>  Why would you change the behavior, instead of just clarifying
>  the doc?
> 
> I generally prefer the behavior to be as strict as possible.

Let's not consider changing long-established behavior for purely
theoretical or philosophical reasons.

> Consider
> (foo-mode 'disable)
> If you read such code, do you assume that this enables foo-mode?

It would be a silly thing to do, so it would be worth a bug report.
However, I don't really believe someone in their right minds would do
something like that.

> However, in this case I guess it's too late, and fixing the documentation is 
> indeed more appropriate.

Exactly.

> Probably this should be reworded so that the Lisp case doesn't refer to the 
> interactive case at all. Making the
> documentation obvious is more important than avoiding repetition.

Sorry, I disagree. with the last sentence.  Repetition is a source for
confusion.