these 2 derivations will be built:
  /nix/store/06fq0asqbhriawyp9bhw6wrdnw7n008i-cargo-vendor-dir.drv
  /nix/store/wh06xy9c3zvj2cpgyjcxbpp1ji791yy7-fast-nix-gc-proptest-0.1.0.drv