flake.nix: replace fenix with rust-overlay

flake.lock

@@ -1,33 +1,12 @@
 {
   "nodes": {
-    "fenix": {
-      "inputs": {
-        "nixpkgs": [
-          "nixpkgs"
-        ],
-        "rust-analyzer-src": "rust-analyzer-src"
-      },
-      "locked": {
-        "lastModified": 1715581585,
-        "narHash": "sha256-/JjvIn1NXW3yOaDcD8Me987/QcXjo+rhg+uThasPAnI=",
-        "owner": "nix-community",
-        "repo": "fenix",
-        "rev": "2c4905096782e8e908205e7fa54ef987fba62793",
-        "type": "github"
-      },
-      "original": {
-        "owner": "nix-community",
-        "repo": "fenix",
-        "type": "github"
-      }
-    },
     "nixpkgs": {
       "locked": {
-        "lastModified": 1715534503,
-        "narHash": "sha256-5ZSVkFadZbFP1THataCaSf0JH2cAH3S29hU9rrxTEqk=",
+        "lastModified": 1734649271,
+        "narHash": "sha256-4EVBRhOjMDuGtMaofAIqzJbg4Ql7Ai0PSeuVZTHjyKQ=",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "2057814051972fa1453ddfb0d98badbea9b83c06",
+        "rev": "d70bd19e0a38ad4790d3913bf08fcbfc9eeca507",
         "type": "github"
       },
       "original": {
@@ -39,24 +18,27 @@
     },
     "root": {
       "inputs": {
-        "fenix": "fenix",
-        "nixpkgs": "nixpkgs"
+        "nixpkgs": "nixpkgs",
+        "rust-overlay": "rust-overlay"
       }
     },
-    "rust-analyzer-src": {
-      "flake": false,
+    "rust-overlay": {
+      "inputs": {
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
       "locked": {
-        "lastModified": 1715255944,
-        "narHash": "sha256-vLLgYpdtKBaGYTamNLg1rbRo1bPXp4Jgded/gnprPVw=",
-        "owner": "rust-lang",
-        "repo": "rust-analyzer",
-        "rev": "5bf2f85c8054d80424899fa581db1b192230efb5",
+        "lastModified": 1735093658,
+        "narHash": "sha256-eIUYGDtairggo7+JXSwN7b6Zr03BJ7tsZL/U0NkDr0s=",
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "rev": "ca249a1d98eff27e92665ac462b9d47f58141925",
         "type": "github"
       },
       "original": {
-        "owner": "rust-lang",
-        "ref": "nightly",
-        "repo": "rust-analyzer",
+        "owner": "oxalica",
+        "repo": "rust-overlay",
         "type": "github"
       }
     }

flake.nix

@@ -1,35 +1,44 @@
 {
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
-    fenix.url = "github:nix-community/fenix";
-    fenix.inputs.nixpkgs.follows = "nixpkgs";
+
+    rust-overlay.url = "github:oxalica/rust-overlay";
+    rust-overlay.inputs.nixpkgs.follows = "nixpkgs";
   };
 
-  outputs = { self, nixpkgs, fenix }@inputs:
+  outputs = { self, nixpkgs, rust-overlay }:
   let
+    inherit (nixpkgs) lib;
+
     systems = [
       "x86_64-linux"
       "aarch64-linux"
       "x86_64-darwin"
       "aarch64-darwin"
     ];
-    forAllSystems = f: nixpkgs.lib.genAttrs systems (system: let
-      toolchain = fenix.packages.${system}.complete;
+
+    forAllSystems = f: lib.genAttrs systems (system: let
       pkgs = import nixpkgs {
         inherit system;
         overlays = [
-          (_: super: let pkgs = fenix.inputs.nixpkgs.legacyPackages.${system}; in fenix.overlays.default pkgs pkgs)
+          (import rust-overlay)
         ];
       };
+
+      rust-bin = rust-overlay.lib.mkRustBin { } pkgs.buildPackages;
+      toolchain = rust-bin.stable.latest.default.override {
+        extensions = [ "rust-src" "rust-analyzer" "rust-std" ];
+      };
     in f system pkgs toolchain);
   in {
-    devShell = forAllSystems (system: pkgs: toolchain: pkgs.mkShell {
-      packages = [
-        (toolchain.withComponents [
-          "cargo" "rustc" "rustfmt" "clippy"
-        ])
-      ];
-      RUST_SRC_PATH = "${toolchain.rust-src}/lib/rustlib/src/rust/library";
+    devShells = forAllSystems (system: pkgs: toolchain: {
+      default = pkgs.mkShell {
+        nativeBuildInputs = [
+          toolchain
+        ];
+
+        RUST_SRC_PATH = "${toolchain}/lib/rustlib/src/rust/library";
+      };
     });
   };
 }