message: Enable rust backtraces in nix shells by default
diff: (rust.override { extensions = [ "rust-src" "rustfmt" ]; })
  pkgs.nixpkgs-fmt
  ];
  + # Print backtraces on panics
  + RUST_BACKTRACE = 1;
  # Certain tools like `rust-analyzer` won't work without this
  RUST_SRC_PATH = "${rust}/lib/rustlib/src/rust/library";
  };
  