ai update nix and cachix

Author: CppCXY

.github/workflows/upload_cachix.yml

@@ -14,7 +14,6 @@ jobs:
       matrix:
         nixChannel:
           - nixos-25.05
-          - nixos-24.11 # remove this when 25.05 is out of beta
           - nixos-unstable
           - nixpkgs-unstable
 

flake.nix

@@ -23,6 +23,9 @@
       let
         overlays = [ rust-overlay.overlays.default ];
         pkgs = import nixpkgs { inherit system overlays; };
+        rustToolchain = pkgs.rust-bin.stable."1.85.0".default.override {
+          extensions = [ "rust-src" "clippy" "rustfmt" ];
+        };
       in
       {
         packages =
@@ -35,11 +38,10 @@
           };
 
         devShells.default = pkgs.mkShell {
-          buildInputs = (with pkgs; [
-            rust-analyzer
-            clippy
-            rustfmt
-          ])
+          buildInputs = [
+            rustToolchain
+            pkgs.rust-analyzer
+          ]
           ++ self.packages.${system}.default.buildInputs
           ++ self.packages.${system}.default.nativeBuildInputs;
         };

nix/packages.nix

@@ -7,11 +7,19 @@ let
       rustPlatform,
       stdenv,
       pkg-config,
+      rust-bin,
     }:
     let
       cargoToml = builtins.fromTOML (builtins.readFile /${root}/crates/${x}/Cargo.toml);
+      rustToolchain = rust-bin.stable."1.85.0".default.override {
+        extensions = [ "rust-src" "clippy" "rustfmt" ];
+      };
+      rustPlatformWithToolchain = rustPlatform.override {
+        rustc = rustToolchain;
+        cargo = rustToolchain;
+      };
     in
-    rustPlatform.buildRustPackage {
+    rustPlatformWithToolchain.buildRustPackage {
       pname = cargoToml.package.name;
       version = cargoToml.package.version;