Symbol’s function definition is void: haskell-mode-after-save-handler

[kephas]

When I save a Haskell file, on a new setup on NixOS, I get the following:

Symbol’s function definition is void: haskell-mode-after-save-handler

The error doesn't go away if I do

(require 'haskell-mode)

But it does if I load the module directly:

(load "/run/current-system/sw/share/emacs/site-lisp/elpa/haskell-mode-20240116.1718/haskell.el")

From other packages experiencing similar issues, I would guess it's an issue with autoload…