The following function gives an incorrect result when compiled natively with comp-speed >= 2. ;; -*- lexical-binding: t; -*- (defun native-comp-bug (body) (let ((x (car body)) (y (cadr body))) (unless (and (natnump x) (natnump y) (<= x y)) (error "")) x)) (native-comp-bug '(3 4)) ;; Expected result: 3 ;; Actual result: 0 The car of the argument is ignored and treated as 0. This appears to be a minimal repro, manually shrunk from the original function discovered in rx.el (rx--translate-bounded-repetition). If either lexical binding, natnump/inequality checks, or error form is removed, the function behaves as expected. Setting comp-speed to 0 or 1 also causes the function to behave as expected, but setting it to 2 or 3 produces the error. In GNU Emacs 28.0.50 (build 1, x86_64-apple-darwin20.2.0, NS appkit-2022.20 Version 11.1 (Build 20C69)) of 2021-02-03 built on QYH2.local Repository revision: e56c26d06f72b58acdc59c7e2958be9b691d3e78 Repository branch: master System Description: macOS 11.2.1 Configured using: 'configure --with-ns --with-modules '--enable-locallisppath=/Library/Application Support/Emacs/${version}/site-lisp:/Library/Application Support/Emacs/site-lisp' --with-xwidgets --with-nativecomp --without-rsvg 'CFLAGS=-I/usr/local/opt/gcc/include -O2 -march=native' 'LDFLAGS=-L/usr/local/opt/gcc/lib/gcc/10 -L/usr/local/opt/libgccjit/lib/gcc/10 -L/usr/local/opt/gcc/lib/gcc/10/gcc/x86_64-apple-darwin20/10.2.0 -I/usr/local/opt/gcc/include -I/usr/local/opt/libgccjit/include'' Configured features: ACL GIF GMP GNUTLS JPEG JSON LCMS2 LIBXML2 MODULES NATIVE_COMP NOTIFY KQUEUE NS PDUMPER PNG THREADS TIFF TOOLKIT_SCROLL_BARS XWIDGETS ZLIB Important settings: value of $LC_ALL: en_US.UTF-8 value of $LC_CTYPE: UTF-8 value of $LANG: en_US.UTF-8 locale-coding-system: utf-8-unix Major mode: Lisp Interaction Minor modes in effect: tooltip-mode: t global-eldoc-mode: t eldoc-mode: t electric-indent-mode: t mouse-wheel-mode: t tool-bar-mode: t menu-bar-mode: t file-name-shadow-mode: t global-font-lock-mode: t font-lock-mode: t blink-cursor-mode: t auto-composition-mode: t auto-encryption-mode: t auto-compression-mode: t line-number-mode: t transient-mark-mode: t Load-path shadows: None found. Features: (shadow sort mail-extr emacsbug message rmc puny dired dired-loaddefs rfc822 mml mml-sec epa derived epg epg-config gnus-util rmail rmail-loaddefs auth-source eieio eieio-core eieio-loaddefs password-cache json map text-property-search time-date mm-decode mm-bodies mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils term/xterm xterm comp comp-cstr warnings subr-x rx cl-seq cl-macs cl-extra help-mode easymenu seq byte-opt gv cl-loaddefs cl-lib bytecomp byte-compile cconv iso-transl tooltip eldoc electric uniquify ediff-hook vc-hooks lisp-float-type mwheel term/ns-win ns-win ucs-normalize mule-util term/common-win tool-bar dnd fontset image regexp-opt fringe tabulated-list replace newcomment text-mode elisp-mode lisp-mode prog-mode register page tab-bar menu-bar rfn-eshadow isearch timer select scroll-bar mouse jit-lock font-lock syntax facemenu font-core term/tty-colors frame minibuffer cl-generic cham georgian utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean japanese eucjp-ms cp51932 hebrew greek romanian slovak czech european ethiopic indian cyrillic chinese composite charscript charprop case-table epa-hook jka-cmpr-hook help simple abbrev obarray cl-preloaded nadvice button loaddefs faces cus-face pcase macroexp files window text-properties overlay sha1 md5 base64 format env code-pages mule custom widget hashtable-print-readable backquote threads xwidget-internal kqueue cocoa ns lcms2 multi-tty make-network-process nativecomp emacs) Memory information: ((conses 16 79127 4281) (symbols 48 8088 1) (strings 32 20784 4357) (string-bytes 1 680668) (vectors 16 13082) (vector-slots 8 220094 8657) (floats 8 27 13) (intervals 56 213 0) (buffers 984 11))