these 3 derivations will be built:
  /nix/store/r70kx0q22vbpb3j9mbihav2z16cfqy27-source.drv
  /nix/store/hw8fc6li6d6bq9wydk2h56zrxmyicarh-collie-1.13.3.drv
  /nix/store/wy1jdrpd94ykkyp19kwznybj012iz7cj-check-collie.drv