these 3 derivations will be built:
  /nix/store/407n97jhw7jvi9l8v66s42hp325sh8a7-source.drv
  /nix/store/va0a7r0sy3bxgbqj1vwvfk3xqk673fy4-collie-1.19.2.drv
  /nix/store/w71vc0wqajm5krf5k2av6pk9wfgm4yib-check-collie.drv