fix: make shell use proper msrv

default.nix

@@ -1,15 +1,13 @@
 {
   lib,
   stdenv,
-  rust-bin, # From overlay
+  rust,
   makeRustPlatform,
   packageToml,
-  rust,
   libiconv,
   darwin,
   python3,
-}: let
-  mkPackage = rust:
+}:
 (makeRustPlatform {
   cargo = rust;
   rustc = rust;
@@ -28,11 +26,10 @@
   cargoLock.lockFile = ./Cargo.lock;
 
   nativeBuildInputs = [rust];
-			buildInputs = (lib.optional stdenv.isDarwin [
+  buildInputs = lib.optional stdenv.isDarwin [
     libiconv
     darwin.apple_sdk.frameworks.Foundation
-				]);
+  ];
 
   nativeCheckInputs = [python3];
-    };
-in (mkPackage rust-bin.stable.latest.minimal)
+}

flake.nix

@@ -33,7 +33,10 @@
 
         devShells = pkgs.callPackages ./shell.nix {inherit packageToml self';};
 
-        packages.default = pkgs.callPackage ./default.nix {inherit packageToml;};
+        packages.default = pkgs.callPackage ./default.nix {
+          inherit packageToml;
+          rust = pkgs.rust-bin.stable.latest.minimal;
+        };
       };
     };
 }