auth-source.el requires eieio, which does (add-hook 'help-fns-describe-function-functions 'eieio-help-generic) and `eieio-help-generic' obviously doesn't treat this case right. Thanks, Michael. In GNU Emacs 24.3.50.3 (x86_64-unknown-linux-gnu, GTK+ Version 3.8.6) of 2014-01-29 on drachen Windowing system distributor `The X.Org Foundation', version 11.0.11405000 System Description: Debian GNU/Linux testing (jessie)