these 3 derivations will be built:
  /nix/store/sn2s0hhafj93yyi97r272dq6jlsvsk6z-source.drv
  /nix/store/f38xlpsl6w64d08zk3ddklfz4f73c20i-collie-1.24.1.drv
  /nix/store/khx44iq4zh2mw0i5qrvd3v5lxhqgwyl6-check-collie.drv