Subject: Re: bug#14831: cl-member warnings during bootstrap

From: Stefan Monnier <[email-masked]>
Date: Mon, 22 Jul 2013 16:40:27 -0400

>> Aha!  So it's the compiler-macro of add-to-list which turns an
>> add-to-list call into a cl-pushnew call, which is then macro-expanded to
>> something that uses cl-member, which should be turned into a plain
>> `member' by `cl--compiler-macro-member'.  So it can be fixed by changing
>> the compiler-macro of add-to-list not to use cl-pushnew.

I installed the patch below which tightens things up a bit.

        Stefan

=== modified file 'lisp/subr.el'
--- lisp/subr.el	2013-07-19 12:18:16 +0000
+++ lisp/subr.el	2013-07-22 16:46:55 +0000
@@ -1498,9 +1498,10 @@
       ;; FIXME: Something like this could be used for `set' as well.
       (if (or (not (eq 'quote (car-safe list-var)))
               (special-variable-p (cadr list-var))
-              (and append compare-fn))
+              (not (macroexp-const-p append)))
           exp
         (let* ((sym (cadr list-var))
+               (append (eval append))
                (msg (format "`add-to-list' can't use lexical var `%s'; use `push' or `cl-pushnew'"
                             sym))
                ;; Big ugly hack so we only output a warning during
@@ -1513,13 +1514,17 @@
                           (when (assq sym byte-compile--lexical-environment)
                             (byte-compile-log-warning msg t :error))))
                (code
-                (if append
                     (macroexp-let2 macroexp-copyable-p x element
-                    `(unless (member ,x ,sym)
-                       (setq ,sym (append ,sym (list ,x)))))
+                  `(unless ,(if compare-fn
+                                (progn
                   (require 'cl-lib)
-                  `(cl-pushnew ,element ,sym
-                               :test ,(or compare-fn '#'equal)))))
+                                  `(cl-member ,x ,sym :test ,compare-fn))
+                              ;; For bootstrapping reasons, don't rely on
+                              ;; cl--compiler-macro-member for the base case.
+                              `(member ,x ,sym))
+                     ,(if append
+                          `(setq ,sym (append ,sym (list ,x)))
+                        `(push ,x ,sym))))))
           (if (not (macroexp--compiling-p))
               code
             `(progn