bug#11241: 24.1.50; emacs-lock is ill uncompiled (lexical binding problem?)

[Stefan Monnier]

>> You don't get that error when you use the compiled code, however.
> Stefan, I can "fix" this for 24.1 just by making emacs-lock.el not use
> lexical-binding.  But is this difference between compiled and
> non-compiled code a bug in the lexical-binding support or something
> expected?

IIRC the problem is that it's not clear whether (<function> <args>)
should treat <function> as an expression or a value.

The compiler handles such as call like (funcall #'<function> <args>)
whereas the interpreter handles it like (funcall '<function> <args>).
In dynamically scoped Elisp, there is no difference between the two, but
not with lexical scoping.
The patch below should work around the difference.

Note that using define-minor-mode's `arg' is not recommended
[ But no, I don't have a good replacement to suggest, other than to
  split the code into two functions, one behaving as a normal boolean
  minor mode and the other accepting the extra possible values. ]


        Stefan


=== modified file 'lisp/emacs-lisp/easy-mmode.el'
--- lisp/emacs-lisp/easy-mmode.el       2012-02-25 05:53:29 +0000
+++ lisp/emacs-lisp/easy-mmode.el       2012-04-14 12:41:01 +0000
@@ -260,7 +260,7 @@
         ;; repeat-command still does the toggling correctly.
         (interactive (list (or current-prefix-arg 'toggle)))
         (let ((,last-message (current-message)))
-           (,@(if setter (list setter)
+           (,@(if setter `(funcall #',setter)
                 (list (if (symbolp mode) 'setq 'setf) mode))
             (if (eq arg 'toggle)
                 (not ,mode)