flake: add rust-overlay for nightly rust

flake.lock

@@ -19,9 +19,30 @@
     "root": {
       "inputs": {
         "nixpkgs": "nixpkgs",
+        "rust-overlay": "rust-overlay",
         "systems": "systems"
       }
     },
+    "rust-overlay": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1746758179,
+        "narHash": "sha256-JECUw1YBEsTsVauvupRzE5ykZaJoyhHCpoY87ZZJGas=",
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "rev": "4fd00513eac6b6140c5dced3e1b8133e2369a0f8",
+        "type": "github"
+      },
+      "original": {
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "type": "github"
+      }
+    },
     "systems": {
       "locked": {
         "lastModified": 1689347949,

flake.nix

@@ -3,29 +3,35 @@
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
     systems.url = "github:nix-systems/default-linux";
+    rust-overlay = {
+      url = "github:oxalica/rust-overlay";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
   };
 
   outputs = inputs: let
-    eachSystem = inputs.nixpkgs.lib.genAttrs (import inputs.systems);
+    inherit (inputs.nixpkgs) lib;
-    pkgsFor = inputs.nixpkgs.legacyPackages;
+    systems = [
+      "x86_64-linux"
+      "aarch64-linux"
+      "x86_64-darwin"
+      "aarch64-darwin"
+    ];
+    eachSystem = lib.genAttrs systems;
+    pkgsFor = eachSystem (system:
+      import inputs.nixpkgs {
+        localSystem.system = system;
+        overlays = [(import inputs.rust-overlay)];
+      });
   in {
-    packages = eachSystem (system: {
-      default = inputs.self.packages.${system}.ralc;
-      ralc = pkgsFor.${system}.callPackage ./nix/package.nix {};
-    });
-
     devShells = eachSystem (system: {
       default = pkgsFor.${system}.mkShell {
         packages = builtins.attrValues {
           inherit
-            (pkgsFor.${system})
+            (pkgsFor.${system}.rust-bin.nightly.latest)
             cargo
             rustc
             rustfmt
-            bacon
-            ;
-          inherit
-            (pkgsFor.${system}.rustPackages)
             clippy
             ;
         };