these 2 derivations will be built:
  /nix/store/lcsmly69f3s0skmyj8rjhwhhvqrh3ws9-iets-0.1.0.drv
  /nix/store/4p49mjg6rlpiqy7irjk0n9jzdk60f8j7-iets-diff-e2e.drv