A simple rust devshell flake for direnv

flake.nix

{
  description = "A basic rust devshell flake";
  inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
  inputs.flake-utils.url = "github:numtide/flake-utils";

  outputs = { self, nixpkgs, flake-utils }:
    flake-utils.lib.eachDefaultSystem (system:
      let pkgs = nixpkgs.legacyPackages.${system};
      in {
        devShells.default =
          pkgs.mkShell { buildInputs = with pkgs; [ cargo rustc ]; };
      });
}