Further simplify flake

default.nix

@@ -1,15 +1,5 @@
-{
-  pkgs,
-  nixpkgs,
-  system,
-  rust-overlay,
-  rustVersion,
-}:
+{ pkgs }:
 let
-  rustPkgs = import nixpkgs {
-    inherit system;
-    overlays = [ (import rust-overlay) ];
-  };
 in
 {
   app = pkgs.rustPlatform.buildRustPackage {

flake.nix

@@ -49,14 +49,7 @@
         system:
         let
           pkgs = nixpkgs.legacyPackages.${system};
-          code = pkgs.callPackage ./. {
-            inherit
-              nixpkgs
-              system
-              rust-overlay
-              rustVersion
-              ;
-          };
+          code = import ./default.nix { inherit pkgs; };
         in
         {
           default = code.app;