I think the function tags--compat-initialize in etags.el is calling fileloop-initialize in fileloop.el with the second and thirds arguments swapped. [etags.el, line 1786] (defun tags--compat-initialize (initialize) (fileloop-initialize (tags--compat-files initialize) (if tags-loop-operate (lambda () (tags-loop-eval tags-loop-operate)) (lambda () (message "Scanning file %s...found" buffer-file-name) nil)) (lambda () (tags-loop-eval tags-loop-scan)))) whereas: [fileloop.el, line 62] (defun fileloop-initialize (files scan-function operate-function) ... ) These files are dated 2020 and 2022 respectively and I believe they are the latest (full version info below) Simply modifying tags--compat-initialize by swapping the second and third args in the call to fileloop-initialize would fix this I think. I found this because po-tags-search in po-mode.el doesn't work properly for me, and it requires etags for its operation. Thanks, Peter --- In GNU Emacs 27.1 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.24.24, cairo version 1.16.0) of 2021-03-27, modified by Debian built on x86-conova-01 Windowing system distributor 'The X.Org Foundation', version 11.0.12011000 System Description: Debian GNU/Linux 11 (bullseye) Recent messages: Saving file /home/peter/Projects/po-mode/po-mode-0.21/po-mode.el... Wrote /home/peter/Projects/po-mode/po-mode-0.21/po-mode.el Mark saved where search started [2 times] Mark set Saving file /home/peter/Projects/po-mode/po-mode-0.21/po-mode.el... Wrote /home/peter/Projects/po-mode/po-mode-0.21/po-mode.el Mark saved where search started Mark set Beginning of buffer Making completion list... 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