anchor.diff:      ];
   
       environment.etc = {
  -      "systemd/user".source = generateUnits "user" cfg.user.units upstreamUserUnits [];
  +      "systemd/user".source = generateUnits "user" cfg.units upstreamUserUnits [];
   
         "systemd/user.conf".text = ''
           [Manager]
  -        ${config.systemd.user.extraConfig}
  +        ${cfg.extraConfig}
         '';
       };
   
       systemd.user.units =
  -         mapAttrs' (n: v: nameValuePair "${n}.path"    (pathToUnit    n v)) cfg.user.paths
  -      // mapAttrs' (n: v: nameValuePair "${n}.service" (serviceToUnit n v)) cfg.user.services
  -      // mapAttrs' (n: v: nameValuePair "${n}.slice"   (sliceToUnit   n v)) cfg.user.slices
  -      // mapAttrs' (n: v: nameValuePair "${n}.socket"  (socketToUnit  n v)) cfg.user.sockets
  -      // mapAttrs' (n: v: nameValuePair "${n}.target"  (targetToUnit  n v)) cfg.user.targets
  -      // mapAttrs' (n: v: nameValuePair "${n}.timer"   (timerToUnit   n v)) cfg.user.timers;
  +         mapAttrs' (n: v: nameValuePair "${n}.path"    (pathToUnit    n v)) cfg.paths
  +      // mapAttrs' (n: v: nameValuePair "${n}.service" (serviceToUnit n v)) cfg.services
  +      // mapAttrs' (n: v: nameValuePair "${n}.slice"   (sliceToUnit   n v)) cfg.slices
  +      // mapAttrs' (n: v: nameValuePair "${n}.socket"  (socketToUnit  n v)) cfg.sockets
  +      // mapAttrs' (n: v: nameValuePair "${n}.target"  (targetToUnit  n v)) cfg.targets
  +      // mapAttrs' (n: v: nameValuePair "${n}.timer"   (timerToUnit   n v)) cfg.timers;
   
       # Generate timer units for all services that have a ‘startAt’ value.
       systemd.user.timers =
  
positive.code: { config, lib, pkgs, utils, ... }:
  with utils;
  with systemdUtils.unitOptions;
  with lib; let
    cfg = config.systemd;
  
    systemd = cfg.package;
  
    inherit
      (systemdUtils.lib)
  
negative.code:     serviceToUnit
      socketToUnit
      timerToUnit
      pathToUnit;
  
    upstreamUserUnits = [
      "app.slice"
  