$ nix-shell -p cargo

output path ‘/nix/store/qmp7gabngcaqvndl5andafpvispi90mb-cargo-d814fcb’ should have r:sha256 hash ‘0sppd3x2cacmbnypcjip44amnh66lrrbwwzsbz8rqf3nq2ah496x’, instead has ‘1c9h5qiwfq0f7z9rpfkl23il4qlfm6bk97c78gk7ish6gsy9c1d7’
cannot build derivation ‘/nix/store/bcin2sfxmgjm3f8j9jxkcpykihcclj18-cargo-2015-05-13.drv’: 1 dependencies couldn't be built