Re: [Emacs-diffs] master 5e43955 1/2: Don't declare vc-exec-after anymore

[Eli Zaretskii <eliz@gnu.org>]

> Date: Thu, 22 Oct 2015 18:04:39 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: lekktu@gmail.com, emacs-devel@gnu.org
> 
> FWIW, on my system I see that warning with all the vc-*.el files that
> call vc-run-delayed.  The only exception is vc-svn.el, and the reason
> is this single line:
> 
>   (autoload 'vc-expand-dirs "vc")
> 
> If you remove it, the warning will appear in vc-svn.el as well.
> (Loading vc loads vc-dispatcher as a side effect.)
> 
> Another data point: replace this:
> 
>   (eval-when-compile (require 'vc))
> 
> with this:
> 
>   (require 'vc)
> 
> and the warning also goes way.  So evidently there's some difference
> between these two, or maybe a byte-compiler bug.

I think bug#21724 supplies an answer: eval-when-compile makes this
function known _at_compile_time_, but the warning says it might not be
known _at_run_time_.

IOW, for a macro it is enough to use eval-when-compile, but if that
macro calls a function, the function should be either auto-loaded, or
the package that defines that function should be require'd.

Does this make sense?