these 2 derivations will be built:
  /nix/store/2k5w0m4ck3k7m9gcdcgdxgyfzn22nmad-cargo-llvm-cov-0.9.0.drv
  /nix/store/75qy5m88xba5y711c2mgrjdmqvyq7iw3-nix-shell.drv