these 2 derivations will be built:
  /nix/store/sh16gh8pp92zfwqmsqfcvla2vqsz5das-iets-0.1.0.drv
  /nix/store/1qrwlynwr9qzfqfcg4wrgi8yfq8sgamc-iets-diff-e2e.drv