M-x smerge-mode
C-x ^
"command-execute: Wrong type argument: commandp, smerge-basic-map"

Regression from 2ae3b66fa80ea6ae7256279e36b1ab2c5d2227eb
(Mon Oct 18 00:35:32 2021 +0200).

In GNU Emacs 29.0.50 (build 4, x86_64-pc-linux-gnu, GTK+ Version 3.24.30, cairo version 1.17.4)