incorrect warning when byte compiling?

[Richard Hansen <rhansen@bbn.com>]

Hi all,

I'm getting a warning when byte compiling that I think shouldn't be a 
warning.

I'm using Emacs 23.3.1 on Linux.  If I put the following in foo.el:

     (defun whitespace-redraw ()
       (eval-when-compile (require 'whitespace nil t))
       (when (require 'whitespace nil t)
         (if whitespace-mode
             (whitespace-mode 0))
         (whitespace-mode 1)))

and then byte compile it:

     emacs -Q --batch --eval '(byte-compile-file "foo.el")'

I get the following warning:

     In end of data:
     foo.el:7:1:Warning: the function `whitespace-mode' might not be 
defined at
         runtime.
     Wrote foo.elc

Yes, whitespace-mode can be undefined at runtime, but only if the 
whitespace feature isn't available.  If whitespace is NOT available, the 
body of the 'when' will not execute, so it won't try to execute the 
undefined whitespace-mode function.  If whitespace IS available, 
whitespace-mode is guaranteed to be defined.  Either way, there's no way 
Emacs will try to execute an undefined whitespace-mode function.

So why is Emacs printing the warning?

Is this a bug/limitation in the Emacs byte compiler?  Or is there a 
subtle bug in my code?

It's easy enough to silence this warning (e.g., with (when (fboundp 
'whitespace-mode) ...)), but I want to know why Emacs thinks this is a 
problem.

Thanks,
Richard