these 3 derivations will be built:
  /nix/store/laryszksyq15q0454nmkwc28pqd4hb4v-source.drv
  /nix/store/bhj24y26jxayk4iyipd0j3vb6smldqmk-collie-1.15.3.drv
  /nix/store/3bjz390k380fjfhn7gg6yv60ccff0wrc-check-collie.drv