these 2 derivations will be built:
  /nix/store/71sypv5fgdvw9xglqsb57z0rqlfmyicj-cargo-vendor-dir.drv
  /nix/store/9w3k3wvw42wcakgn8q9qf1hgrabvli6c-horae-tests-0.1.0.drv