these 2 derivations will be built:
  /nix/store/x4hcihsbd7ccxfwfxd10xspfs0v9z4gd-cargo-vendor-dir.drv
  /nix/store/5s4xigbq3zf0ya4z0f9xnsmlmq0qnh0f-nixfmt-rs-0.5.3.drv