Macro expansion containing ‘interactive’

[Marcus Harnisch]

In an attempt to create a compatibility wrapper for the new optional 
mode list parameter of ‘interactive’ I am facing difficulties. The 
definition looks like this:

  (defmacro foo--interactive (&optional arg-descriptor)
    "Compatibility wrapper to support `interactive' with additional
  MODE parameter (Emacs 28+)."
    ;; https://lars.ingebrigtsen.no/2021/02/16/command-discovery-in-emacs/
    (if (and (featurep 'emacs)
             (>= emacs-major-version 28))
        `(interactive ,arg-descriptor foo-mode)
      `(interactive ,arg-descriptor)))

According to ‘(macroexpand '(foo--interactive "bar"))’ the expansion 
itself seems to work. However, I still see all of foo-mode's interactive 
functions being completed with ‘M-x foo TAB’ from buffer ‘*scratch*’ 
(which is not in ‘foo-mode’).

The Emacs process itself is started with:

  emacs -l foo-mode.el -Q

Any ideas how to debug/fix this?

Thanks,
Marcus