From be3cae9f559015219af07dd63170dded2fb64056 Mon Sep 17 00:00:00 2001 From: Stefan Monnier Date: Fri, 11 Aug 2023 23:14:05 -0400 Subject: [PATCH] * lisp/emacs-lisp/cl-macs.el (cl--labels-convert): Fix bug#65017 This fixes what I consider to be the core of the bug, by handling `cl--labels-convert-cache` more carefully (i.e. being more careful how we look up its value and by flushing it ASAP). --- lisp/emacs-lisp/cl-macs.el | 14 +++++++++++++- 1 file changed, 13 insertions(+), 1 deletion(-) diff --git a/lisp/emacs-lisp/cl-macs.el b/lisp/emacs-lisp/cl-macs.el index 0a3181561bd..87b6801bf00 100644 --- a/lisp/emacs-lisp/cl-macs.el +++ b/lisp/emacs-lisp/cl-macs.el @@ -2037,7 +2037,17 @@ a `let' form, except that the list of symbols can be computed at run-time." ;; *after* handling `function', but we want to stop macroexpansion from ;; being applied infinitely, so we use a cache to return the exact `form' ;; being expanded even though we don't receive it. - ((eq f (car cl--labels-convert-cache)) (cdr cl--labels-convert-cache)) + ;; In Common Lisp, we'd use the `&whole' arg instead (see + ;; "Macro Lambda Lists" in the CLHS). + ((let ((symbols-with-pos-enabled nil)) ;Don't rewrite #' => #' + ;; FIXME: The above `let' is incorrectly optimized away (bug#65017). + (eq f (car cl--labels-convert-cache))) + ;; This value should be `eq' to the `&whole' form. + ;; If this is not the case, we have a bug. + (prog1 (cdr cl--labels-convert-cache) + ;; Drop it, so it can't accidentally interfere with some + ;; unrelated subsequent use of `function' with the same symbol. + (setq cl--labels-convert-cache nil))) (t (let* ((found (assq f macroexpand-all-environment)) (replacement (and found @@ -2045,6 +2055,8 @@ a `let' form, except that the list of symbols can be computed at run-time." (funcall (cdr found) cl--labels-magic))))) (if (and replacement (eq cl--labels-magic (car replacement))) (nth 1 replacement) + ;; FIXME: Here, we'd like to return the `&whole' form, but since ELisp + ;; doesn't have that, we approximate it via `cl--labels-convert-cache'. (let ((res `(function ,f))) (setq cl--labels-convert-cache (cons f res)) res)))))) -- 2.39.2