these 3 derivations will be built:
  /nix/store/rqxrv4hwsbl3kjrbsf4az2y6vj0jbsdv-source.drv
  /nix/store/facc9zgirkch9xipl1knlrmimijpfrap-collie-1.15.0.drv
  /nix/store/6azpvza688vw8qn5zykr6njygrz7rjy0-check-collie.drv