bug#30285: dired-do-chmod vs. top line of dired

[martin rudalics]

> Agreed.  Simplicity is the hallmark of Emacs.

Wouldn't this

-  (let* ((files (dired-get-marked-files t arg))
+  (let* ((files (or (dired-get-marked-files t arg)
+                    (user-error "No files specified")))

call for an extra argument to 'dired-get-marked-files' to emit the
user error right there?  If it's TRT in your cases, it might give
coders a heads-up that it's TRT in their cases as well.

martin