Hello, This bug is twofold and appears to be related to bug#62446 and bug#61917. I produce a much smaller reproducer that generates the same kind of error as bug#61917, namely `(wrong-number-of-arguments # 2)`. Segfaults only occur after the following commit: commit 52b67740d10df8ca539fdc2c7d50283997683141 Author: Mattias Engdegård Date: Sat Mar 25 15:38:00 2023 +0100 Generalise a LAP optimisation rule * lisp/emacs-lisp/byte-opt.el (byte-optimize-lapcode): Accept (stack-set 1) as equivalent to (discardN-preserve-tos 1) in a rule previously overlooked. This is usually beneficial in code size and almost always shortens dynamic paths. Common setup: 1. mkdir repro 2. Put attached init.el and main.c inside (technically, main.c need not be in repro) ——— To reproduce bug#61917: 1. git checkout master 2. configure --with-native-compilation \ --without-x \ --without-ns \ --without-compress-install \ --with-native-compilation \ --with-json \ --with-tree-sitter 3. make bootstrap 4. emacs --init-directory ../repro 5. Check messages, and ye shall find the bug message. ——— To reproduce segfault: 1. git checkout 52b67740d10df8ca539fdc2c7d50283997683141 2. Perform same configure and build commands as above. 3. emacs --init-directory ../repro ../repro/main.c (loading main.c is *required*, the segfault does not fire otherwise) 4. (In emacs) M-x 5. Fatal error 11: Segmentation fault Best regards, Jacob Faibussowitsch (Jacob Fai - booss - oh - vitch)