Compilation warnings in cc-mode.el

Compilation warnings in cc-mode.el

[Eli Zaretskii]

I see a few of these when compiling today's bzr:

  cc-mode.el:158:1:Warning: (lambda nil ...) quoted with ' rather than with #'

Re: Compilation warnings in cc-mode.el

[Juanma Barranquero]

On Wed, Jul 20, 2011 at 07:10, Eli Zaretskii <eliz@gnu.org> wrote:

> I see a few of these when compiling today's bzr:
>
>  cc-mode.el:158:1:Warning: (lambda nil ...) quoted with ' rather than with #'

They have been there for a while now. The oldest bootstrap log I have
is from 2011-06-19 and they already appear, and I'm pretty sure
they're older than that.

    Juanma

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Re: Compilation warnings in cc-mode.el

[Lars Magne Ingebrigtsen]

Eli Zaretskii <eliz@gnu.org> writes:

> I see a few of these when compiling today's bzr:
>
>   cc-mode.el:158:1:Warning: (lambda nil ...) quoted with ' rather than with #'

So it's this bit, I guess?

    ;; Being evaluated from source.  Always use the dynamic method to
    ;; work well when `c-lang-defvar's in this file are reevaluated
    ;; interactively.
    `(lambda ()
       (require 'cc-langs)
       (let ((c-buffer-is-cc-mode ',mode)
	     (init (append (cdr c-emacs-variable-inits)
			   (cdr c-lang-variable-inits)))
	     current-var)



-- 
(domestic pets only, the antidote for overdose, milk.)
  bloggy blog http://lars.ingebrigtsen.no/

Re: Compilation warnings in cc-mode.el

[Alan Mackenzie]

Hello, Eli.

On Wed, Jul 20, 2011 at 01:10:56AM -0400, Eli Zaretskii wrote:
> I see a few of these when compiling today's bzr:

>   cc-mode.el:158:1:Warning: (lambda nil ...) quoted with ' rather than with #'

I've had a quite long look at the source code, but can't figure it out.
I've fixed another bug in that area, though, so thanks for drawing my
attention to it.  :-)

I'm not altogether sure what that warning means.  Mostly, a (lamda ...)
isn't quoted at all, surely?  Presumably there's been a change to the
byte compiler to cause these warnings.  But there're 9 of them.  I would
have expected 7 or 14 (one or two for each CC Mode).

I'll carry on looking at this for a wee while.

-- 
Alan Mackenzie (Nuremberg, Germany).

Re: Compilation warnings in cc-mode.el

[Stefan Monnier]

>> cc-mode.el:158:1:Warning: (lambda nil ...) quoted with ' rather than with #'

> I've had a quite long look at the source code, but can't figure it out.
> I've fixed another bug in that area, though, so thanks for drawing my
> attention to it.  :-)

Most likely it's a ',foo in some macro where `foo' is an argument that ends
up being a (lambda ...) in some cases.

> I'm not altogether sure what that warning means.  Mostly, a (lamda ...)
> isn't quoted at all, surely?  Presumably there's been a change to the
> byte compiler to cause these warnings.

Yes, the change is to output a warning when we detect such a case
(i.e. when (quote (lambda ..)) is passed to funcall, apply, and a few
more special-cased functions).  We used to silently change those to
#'(lambda ..), but now we additionally output a warning since the
meaning of the two is subtly different in the presence of lexical-binding.


        Stefan