Re: Warning: `mapcar' called for effect; use `mapc' or `dolist'

[Reiner Steib]

On Mon, Oct 22 2007, Dan Nicolaescu wrote:

> Reiner Steib <address@hidden> writes:
>   > On Mon, Oct 22 2007, Katsumi Yamaoka wrote:
>   > > For instance, `mapcar' used in `gnus-group-highlight-line'
>   > > cannot be replaced with `mapc' even if the compiler warns it.
>   > 
>   > Could the byte-compiler be improved not to warn about such cases?
>   > Here's the relevant code:
>   > 
>   > (defun gnus-group-highlight-line ()
>   >   "Highlight the current line according to `gnus-group-highlight'."
[...]
> It seems that `mailp' is not used in that function. 

`mailp' is used implicitly through the variable `gnus-group-highlight'
which is let-bound to `list'.  `list' is used in the body of the
let-form.

> Adding a use for it makes the warning go away...

Hm, I can't reproduce the warning using `emacs-lisp-byte-compile' with
GNU Emacs 23.0.50.6 (i686-pc-linux-gnu, GTK+ Version 2.10.6) of 2007-10-20.
Too old?

Bye, Reiner.
-- 
       ,,,
      (o o)
---ooO-(_)-Ooo---  |  PGP key available  |  http://rsteib.home.pages.de/