bug#66991: Confusion in interactive-form with commands with bare interactive forms.

[Stefan Monnier]

> I get a failure in /test/src/comp-tests.log in test
> comp-tests-interactive-form, where the test is expecting
>
>     (interactive)
>
> but the result of running the test innards is
>
>     (interactive nil)

I'd argue the test should accept either form.

> ..  I don't understand why I'm only seeing this test failure now.

Indeed, it's odd.

> Maybe it's a new test.

`git log test/lisp/emacs-lisp/comp-tests.el` suggests there's been no
activity there of late.

> OK.  :-)  But I think fixing data.c will be easier and cleaner than
> fixing all the tests which might test it.

I wouldn't call it a fix because I don't think the current behavior is
broken, but I see no problem with `interactive-form` replacing
`(interactive)` for `(interactive nil)` when it can do so cheaply.
It may break other (broken) tests, of course.


        Stefan