these 3 derivations will be built:
  /nix/store/1zsd11zxra39x3b4ix0kmkyynrwj5b78-source.drv
  /nix/store/njvwd746yj0900n43sx4pbj00cwm07ip-collie-1.14.2.drv
  /nix/store/mb46an5snglr6m6ridzwqbxza3nrcbcj-check-collie.drv