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

[Dan Nicolaescu]

Reiner Steib <address@hidden> writes:

  > 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?

I can't either. I thought that adding a use for mailp fixed the
warning for me, I didn't try it before that.