these 2 derivations will be built:
  /nix/store/ixvxqpcdmdd0b2pyvf8d8n42mjgnw40j-iets-0.1.0.drv
  /nix/store/z43mvz8s5f0iha3sybxj5jazbphfdcb1-iets-diff-e2e.drv