I also fixed the long-time occuring error when using the newest version
of the channel (or the unstable one). It turns out to be a simple type
error with the `my.user' attribute. (To be honest the error messages are
quite horrible.)
On another note, I also accidentally bricked my NixOS setup after a
garbage collection and a horrible update. The breakage includes not
being able to use any of the builtin tools of Nix (e.g., nix, nix-env,
nixos-rebuild) due to a shared library error that has been garbage
collected. Which means I have to reinstall it.
(I seem to have a talent for breaking things, if only I'm paid for it.)