these 3 derivations will be built:
  /nix/store/sy4i5d9w8am8wcxhhna768da8jk87613-source.drv
  /nix/store/kjyrmjvim4r4c86q31rsj2znzh6q2kjg-collie-1.20.0.drv
  /nix/store/y939gjiiz74nrx5mb8llr49x2l76rqa7-check-collie.drv