Error: The option value `users.users' in /users-groups.nix is not of type `attribute set of submodules'

I have this configuration:

Since i updated the channel to 20.09, i get this error:

[root@atomic:~]# nixos-rebuild switch
building Nix...
building the system configuration...
error: The option value `users.users' in `/nix/var/nix/profiles/per-user/root/channels/nixos/nixos/modules/config/users-groups.nix' is not of type `attribute set of submodules'.
(use '--show-trace' to show detailed location information)

It looks like an error in users.users, so i added that section, simplified, into another nixos config:

  users.extraUsers = lib.genAttrs [
  ] (user:  {
    isNormalUser = true;
    home = "/var/www/${user}";
    openssh.authorizedKeys.keys = [ "pubkey" ];

but that works without issues.

So i guess the error message is misleading. How can i solve this?

The issue was still this: #26 - users.users - nixos-config -

In 20.03, there was a warning, but i ignored it until now.

Solution was this change atomic: upgrade to 20.09 · 63dab2c1f3 - nixos-config - in modules/satzgenerator.nix.