nix.package = pkgs.nixUnstable.overrideAttrs (old: {
    src = pkgs.fetchFromGitHub {
      owner = "nixos";
      repo = "nix";
      rev = "f435634a29551754d5f7303b0a60cd8fe2df2079";
      sha256 = "1hwv32bfpk26281zxgnr25kvhic9y8vs6h0fcidpf34xzk3dkcxc";
    };
  });