these 3 derivations will be built:
  /nix/store/gxj3knianfr2xknvgaj3l5g4yb27ay70-source.drv
  /nix/store/77svvcrmf7ly1d453j0fq43m9n4p0150-collie-1.28.4.drv
  /nix/store/6kkdc7zlnrcvs74xhvfpmvvv5chfnf96-check-collie.drv