diff --git a/flake.nix b/flake.nix
index 26109ec..c62878e 100644
--- a/flake.nix
+++ b/flake.nix
@@ -10,9 +10,15 @@
     inputs.flake-utils.lib.eachDefaultSystem (
       system:
       let
-        pkgs = import inputs.nixpkgs { inherit system; };
+        pkgs = inputs.nixpkgs.legacyPackages.${system};
+        lib = inputs.nixpkgs.lib;
+
+        src = lib.sourceFilesBySuffices ./. [
+          "Cargo.toml"
+          "Cargo.lock"
+          ".rs"
+        ];
 
-        src = ./.;
         cargoToml = fromTOML (builtins.readFile "${src}/Cargo.toml");
         name = cargoToml.package.name;