GNU bug report logs - #56739
29.0.50; `cl-psetq' and `cl-psetf' fail to recognize symbol macros

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From: Michael Heerdegen <michael_heerdegen <at> web.de>
To: Wing Hei Chan <whmunkchan <at> outlook.com>
Cc: 56739 <at> debbugs.gnu.org
Subject: bug#56739: 29.0.50; `cl-psetq' and `cl-psetf' fail to recognize symbol macros
Date: Wed, 03 Aug 2022 02:20:55 +0200

[Message part 1 (text/plain, inline)]

Hello,

I think we can fix this (both cases mentioned) similarly as in cl-letf:

[0001-WIP-Fix-symbol-macros-used-in-cl-psetf-Bug-56739.patch (text/x-diff, inline)]

From 29ea21a751ab6e71b2fb34c781131e31fc7b950d Mon Sep 17 00:00:00 2001
From: Michael Heerdegen <michael_heerdegen <at> web.de>
Date: Wed, 3 Aug 2022 02:06:16 +0200
Subject: [PATCH] WIP: Fix symbol macros used in cl-psetf (Bug#56739)

---
 lisp/emacs-lisp/cl-macs.el | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/lisp/emacs-lisp/cl-macs.el b/lisp/emacs-lisp/cl-macs.el
index 78d19db479..f3051752ba 100644
--- a/lisp/emacs-lisp/cl-macs.el
+++ b/lisp/emacs-lisp/cl-macs.el
@@ -2653,12 +2653,17 @@ cl-psetf

 \(fn PLACE VAL PLACE VAL ...)"
   (declare (debug setf))
-  (let ((p args) (simple t) (vars nil))
+  (let ((p args) (simple t) (vars nil)
+        (smacros (alist-get :cl-symbol-macros macroexpand-all-environment)))
     (while p
-      (if (or (not (symbolp (car p))) (cl--expr-depends-p (nth 1 p) vars))
-	  (setq simple nil))
-      (if (memq (car p) vars)
-	  (error "Destination duplicated in psetf: %s" (car p)))
+      (when (or (not (symbolp (car p)))
+                (assq (car p) smacros)
+                (and (symbolp (nth 1 p))
+                     (assq (nth 1 p) smacros))
+                (cl--expr-depends-p (nth 1 p) vars))
+	(setq simple nil))
+      (when (memq (car p) vars)
+	(error "Destination duplicated in psetf: %s" (car p)))
       (push (pop p) vars)
       (or p (error "Odd number of arguments to cl-psetf"))
       (pop p))
--
2.30.2

[Message part 3 (text/plain, inline)]

But I'm not a fan of symbol macros any more: the concept sounds nice
first, but actually you only save one pair of parens when coding while
they introduce a special case that one always has too keep in mind for
macro expansions: any symbol might not just be a symbol.

I guess this is not the only place where they are not handled correctly.

Michael.

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