Re: [Emacs-diffs] master b7fa6b1 1/4: Simplify use of FOR_EACH_TAIL

[Eli Zaretskii]

> From: Paul Eggert <address@hidden>
> Date: Sun, 5 Feb 2017 21:23:43 -0800
> 
>    Lisp_Object tail;
>    FOR_EACH_TAIL (tail, list)
>      if (EQ (XCAR (tail), elt))
>        return true;
> 
> but this was annoying both because the user must declare 'tail', and because 
> typically 'tail' should not survive the loop but the declaration forces it to 
> survive.

Why is it so important to make sure it doesn't survive the loop?  If
for optimizations, then I'd expect modern compilers to be smart enough
to produce the same code whether it does or doesn't survive.

We have similar macros elsewhere, e.g. FOR_EACH_FRAME,
FOR_EACH_BUFFER, etc.  It's IMO a pity to have this one different.