these 2 derivations will be built:
  /nix/store/k6a0npwxkjpvwn9il0kqkm2vzfq49d54-cargo-vendor-dir.drv
  /nix/store/83pa7jq6bmqswpp7pynqnbsrld78s9yy-horae-tests-0.1.0.drv