these 3 derivations will be built:
  /nix/store/056nm4rv39s60hgdz3d6hng96hgkz8i9-source.drv
  /nix/store/df3xs0gis7hk34c2wxrpczx6j89s09d9-collie-1.14.1.drv
  /nix/store/7l9vr7ki2vw74578xm90l3pmw1l7ragn-check-collie.drv