bug#64292: 30.0.50; setf strange when lexical-binding is nil

bug#64292: 30.0.50; setf strange when lexical-binding is nil

[Katsumi Yamaoka]

Hi,

In the *scratch* buffer:

(setq lexical-binding nil)
(require 'nnheader)
(macroexpand '(setf (mail-header-date header) date))
 => (let* ((v #'(lambda (cl-x) (progn (progn (aref cl-x 3)))))
           (v header))
      (\(setf\ funcall\) date v v))

This looks broken, though it gets normal if lexical-binding is t.
Because of this, an old ELisp module doesn't work.  In addition,
the funny portion is replaced with
\(setf\ internal--with-suppressed-warnings\)...
if the code is byte-compiled.

Thanks.

In GNU Emacs 30.0.50 (build 1, x86_64-pc-cygwin, GTK+ Version
 3.22.28, cairo version 1.17.4) of 2023-06-26 built on localhost

bug#64292: 30.0.50; setf strange when lexical-binding is nil

[Mattias Engdegård]

> (setq lexical-binding nil)
> (require 'nnheader)
> (macroexpand '(setf (mail-header-date header) date))
>  => (let* ((v #'(lambda (cl-x) (progn (progn (aref cl-x 3)))))
>            (v header))
>       (\(setf\ funcall\) date v v))
> 
> This looks broken, though it gets normal if lexical-binding is t.
> Because of this, an old ELisp module doesn't work.  In addition,
> the funny portion is replaced with
> \(setf\ internal--with-suppressed-warnings\)...
> if the code is byte-compiled.

This is effectively an encrypted "you should use lexical-binding:t" error message.
Stefan, should we just bypass the suppression here, or the entire `cl--slet` business, in dynbound mode?

bug#64292: 30.0.50; setf strange when lexical-binding is nil

[Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors]

Mattias Engdegård [2023-06-27 15:21:08] wrote:

>> (setq lexical-binding nil)
>> (require 'nnheader)
>> (macroexpand '(setf (mail-header-date header) date))
>>  => (let* ((v #'(lambda (cl-x) (progn (progn (aref cl-x 3)))))
>>            (v header))
>>       (\(setf\ funcall\) date v v))
>> 
>> This looks broken, though it gets normal if lexical-binding is t.
>> Because of this, an old ELisp module doesn't work.  In addition,
>> the funny portion is replaced with
>> \(setf\ internal--with-suppressed-warnings\)...
>> if the code is byte-compiled.
>
> This is effectively an encrypted "you should use lexical-binding:t" error message.
> Stefan, should we just bypass the suppression here, or the entire `cl--slet`
> business, in dynbound mode?

Can someone confirm that the patch below reverts the regression?


        Stefan


diff --git a/lisp/emacs-lisp/cl-macs.el b/lisp/emacs-lisp/cl-macs.el
index aadb498609a..eed7199fcc2 100644
--- a/lisp/emacs-lisp/cl-macs.el
+++ b/lisp/emacs-lisp/cl-macs.el
@@ -247,9 +247,10 @@ cl--slet
   "Like `cl--slet*' but for \"parallel let\"."
   (let ((dyns nil)) ;Vars declared as dynbound among the bindings?
     ;; `seq-some' lead to bootstrap problems.
-    (dolist (binding bindings)
-      (when (macroexp--dynamic-variable-p (car binding))
-        (push (car binding) dyns)))
+    (when lexical-binding
+      (dolist (binding bindings)
+        (when (macroexp--dynamic-variable-p (car binding))
+          (push (car binding) dyns))))
     (cond
      (dyns
       (let ((form `(funcall (lambda (,@(mapcar #'car bindings))

bug#64292: 30.0.50; setf strange when lexical-binding is nil

[Katsumi Yamaoka]

On Tue, 27 Jun 2023 09:36:07 -0400, Stefan Monnier wrote:
> Can someone confirm that the patch below reverts the regression?

The patch did the trick on at least the setf issue.  Thanks.

bug#64292: 30.0.50; setf strange when lexical-binding is nil

[Stefan Monnier via Bug reports for GNU Emacs, the Swiss army knife of text editors]

>> Can someone confirm that the patch below reverts the regression?
> The patch did the trick on at least the setf issue.  Thanks.

I pushed it to `master` (under the "bug#64315" name, tho, didn't
realize there were not the same bug numbers).


        Stefan