these 3 derivations will be built:
  /nix/store/1n3xd281036panwphh5j8j14a85rajfv-source.drv
  /nix/store/q2cqhsfxy65rh3adka9prb6qv9k0dms3-collie-1.13.1.drv
  /nix/store/jyzp2kg2qf9fiqh2zkpihb1r2zl2mzfl-check-collie.drv