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

[Alan Mackenzie]

Hello, Emacs

Consider commands with no arguments, and do interactive-form on them:

(interactive-form 'x-print-frames-dialog) => (interactive "") # a primitive

(interactive-form 'universal-argument) => (interactive nil) # a native
                                                      compiled command.
The result is the same from a byte compiled command.

Write (defun foo () (interactive)) in *scratch*, and C-M-x to evaluate
it:
(interactive-form 'foo) => (interactive).

That's three different inconsistent ways of expressing "(interactive".
This is a bug.  For consistency's sake, two of them must be incorrect.

I believe the correct one is the last of these, "(interactive)" which is
after all, what appears in the Lisp sources.  The fix should be
relatively simple, in Finteractive_form in src/data.c

-- 
Alan Mackenzie (Nuremberg, Germany).