{
  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
  };
  outputs = {
    nixpkgs,
    self,
  }: let
    forAllSystems = fn:
      builtins.foldl' (attrs: system: let
        outputs = fn system;
        outputNames = builtins.attrNames outputs;
      in
        builtins.foldl' (attrs: outName: let
          existing = attrs.${outName} or {};
          new = existing // {${system} = outputs.${outName};};
        in
          attrs // {${outName} = new;})
        attrs
        outputNames) {} ["x86_64-linux" "aarch64-linux"];
  in
    {
      overlays.default = final: prev: {
        nix-ci = final.lib.flip final.callPackage {} ({
          rustPlatform,
          lib,
          makeWrapper,
          nix-eval-jobs,
        }: let
          cargoToml = builtins.fromTOML (builtins.readFile ./Cargo.toml);
        in
          rustPlatform.buildRustPackage {
            pname = cargoToml.package.name;
            version = cargoToml.package.version;
            src = lib.fileset.toSource {
              root = ./.;
              fileset = lib.fileset.unions [
                ./src
                ./Cargo.toml
                ./Cargo.lock
              ];
            };
            nativeBuildInputs = [makeWrapper];
            cargoLock.lockFile = ./Cargo.lock;
            preFixup = ''
              wrapProgram "$out/bin/nix-ci" \
                --prefix PATH : ${lib.makeBinPath [nix-eval-jobs]}
            '';
          });
      };
    }
    // forAllSystems (system: let
      pkgs = import nixpkgs {
        inherit system;
        overlays = [self.overlays.default];
      };
    in {
      devShells.default = import ./shell.nix {inherit pkgs;};
      packages = {
        default = pkgs.nix-ci;
        nix-ci = pkgs.nix-ci;
      };
      checks = self.packages.${system};
    });
}