these 2 derivations will be built:
  /nix/store/vyjmb1f9j6j7slifrmxa48pvkf0mrl6n-iets-0.1.0.drv
  /nix/store/r0fmvg1zx29licf0r0f00a7chc76nj9v-iets-diff-e2e.drv