use flake-parts in rust template

templates/_rust/.envrc

@@ -11,6 +11,8 @@ fi
 
 watch_file nix/**
 watch_file -- **/*.nix
+watch_file Cargo.toml
+watch_file rust-toolchain.toml
 # Adding files to git includes them in a flake
 # But it is also a bit much reloading.
 # watch_file .git/index .git/HEAD

templates/_rust/flake.nix

@@ -1,13 +1,13 @@
 {
-  description = "Rust-Hello";
+  description = "Rust-Package";
 
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+    flake-parts.url = "github:hercules-ci/flake-parts";
     rust-overlay = {
       url = "github:oxalica/rust-overlay";
       inputs.nixpkgs.follows = "nixpkgs";
     };
-    flake-utils.url = "github:numtide/flake-utils";
     crate2nix = {
       url = "github:nix-community/crate2nix";
       inputs.nixpkgs.follows = "nixpkgs";
@@ -15,20 +15,25 @@
   };
 
   outputs = inputs @ {
+    flake-parts,
     crate2nix,
-    flake-utils,
-    nixpkgs,
     rust-overlay,
     ...
   }:
-    flake-utils.lib.eachDefaultSystem (
-      system: let
-        # Overlay pkgs with rust-bin
-        overlays = [(import rust-overlay)];
-        pkgs = import nixpkgs {
-          inherit system overlays;
-        };
+    flake-parts.lib.mkFlake {inherit inputs;} {
+      systems = [
+        "aarch64-linux"
+        "aarch64-darwin"
+        "x86_64-darwin"
+        "x86_64-linux"
+      ];
 
+      perSystem = {
+        pkgs,
+        system,
+        self',
+        ...
+      }: let
         # Use rust-bin to generate the toolchain from rust-toolchain.toml
         rust-toolchain = pkgs.rust-bin.fromRustupToolchainFile ./rust-toolchain.toml;
 
@@ -48,14 +53,20 @@
           inherit pkgs buildRustCrateForPkgs;
         };
       in {
-        packages = rec {
-          hello = cargoNix.rootCrate.build;
-          default = hello;
+        # Overlay pkgs with rust-bin
+        _module.args.pkgs = import inputs.nixpkgs {
+          inherit system;
+          overlays = [(import rust-overlay)];
         };
 
-        devShell = pkgs.mkShell {
+        packages = {
+          hello = cargoNix.rootCrate.build;
+          default = self'.packages.hello;
+        };
+
+        devShells.default = pkgs.mkShell {
           buildInputs = [rust-toolchain];
         };
-      }
-    );
+      };
+    };
 }

templates/_rust/rust-toolchain.toml

@@ -1,3 +1,3 @@
 [toolchain]
-channel = "1.85.0"
+channel = "1.96.0"
 components = [ "rustfmt", "rustc-dev", "rust-analyzer", "rust-src"]