{
  inputs = {
    nixpkgs.url = "github:nixos/nixpkgs/nixos-unstable";
    rust-overlay = {
      url = "github:oxalica/rust-overlay";
      inputs.nixpkgs.follows = "nixpkgs";
    };
  };
  outputs =
    { nixpkgs
    , rust-overlay
    , 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
          rust-overlay.overlays.default


          (final: prev: {
            inherit (prev.lixPackageSets.stable)
              nixpkgs-review
              nix-eval-jobs
              nix-fast-build
              colmena;
          })
        ];
      };
      rust = pkgs.rust-bin.stable.latest.default.override {
        extensions = [
          "rust-src" # for rust-analyzer
          "rust-analyzer"
        ];
      };
    in
    {
      devShells.default = pkgs.mkShell {
        nativeBuildInputs = [ pkgs.nix-eval-jobs rust pkgs.attic-client ];
      };
      packages = {
        default = pkgs.nix-ci;
        nix-ci = pkgs.nix-ci;
      };
      checks = self.packages.${system};
    });
}