Re: [PATCH] gv.el: minor change, cleaning up

[Stefan Monnier <monnier@iro.umontreal.ca>]

> Evaluate `(macroexpand-all `(setf (alist-get key alist) value))` and
> it returns the following:
>
>   (let* () ;; /* bindings omitted */
>     (progn
>      (if p
>          (setcdr p v)
>        (setq alist
>              (cons (setq p
>                          (cons key v))
>                    alist)))
>      v))
>
> It seems to me that `(setq p ..)` is unnecessary,

It's unnecessary for `setf` (and `push`, and `cl-pushnew`, and
`cl-rotatef`, and `cl-callf` ;-) but it can be necessary for more
complex settings.  I can't remember what was the setting where I found
that I needed it, sadly.  Clearly it must be one where we use the getter
(or the setter) after having used the setter.


        Stefan