bug#61730: 30.0.50; Compiler warnings for delq and delete

["Mattias Engdegård" <mattias.engdegard@gmail.com>]

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24 feb. 2023 kl. 17.45 skrev Michael Heerdegen <michael_heerdegen@web.de>:

> Instead of "(setq _ ..." you could better use "(ignore ..."

I would very much like `ignore` to work that way but it currently doesn't. This is probably a bug. Stefan, what about the attached patch?

(I already pushed a fix for proper for-effect behaviour of with-suppressed-warnings to master; hope that is all right.)


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diff --git a/lisp/emacs-lisp/bytecomp.el b/lisp/emacs-lisp/bytecomp.el
index 095468ad978..457efe73886 100644
--- a/lisp/emacs-lisp/bytecomp.el
+++ b/lisp/emacs-lisp/bytecomp.el
@@ -4329,7 +4329,11 @@ byte-compile-goto-if
 
 (defun byte-compile-ignore (form)
   (dolist (arg (cdr form))
-    (byte-compile-form arg t))
+    ;; Compile args for value (to avoid warnings about unused values),
+    ;; emit a discard after each, and trust the LAP peephole optimiser
+    ;; to annihilate useless ops.
+    (byte-compile-form arg)
+    (byte-compile-discard))
   (byte-compile-form nil))
 
 ;; Return the list of items in CONDITION-PARAM that match PRED-LIST.