these 2 derivations will be built:
  /nix/store/j7pzmk6n6wzdnlc3g5xhwzlgprj3j463-iets-0.1.0.drv
  /nix/store/3k7h588mj054g4kaprdmj6xz5yhacyk4-iets-diff-e2e.drv