refactor(nix): use rust-toolchain.toml

flake.lock

@@ -95,7 +95,8 @@
       "inputs": {
         "crane": "crane",
         "flake-utils": "flake-utils_2",
-        "nixpkgs": "nixpkgs"
+        "nixpkgs": "nixpkgs",
+        "rust-overlay": "rust-overlay_2"
       }
     },
     "rust-overlay": {
@@ -123,6 +124,29 @@
         "type": "github"
       }
     },
+    "rust-overlay_2": {
+      "inputs": {
+        "flake-utils": [
+          "flake-utils"
+        ],
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1688265347,
+        "narHash": "sha256-oe3kLnNvw2VWbG4Rp6IWUO5Uu5gF8J2oq8DbqbCsdZ4=",
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "rev": "b8f3db465405014039985f1c5cea92cc29e1b3b5",
+        "type": "github"
+      },
+      "original": {
+        "owner": "oxalica",
+        "repo": "rust-overlay",
+        "type": "github"
+      }
+    },
     "systems": {
       "locked": {
         "lastModified": 1681028828,

flake.nix

@@ -6,6 +6,13 @@
       inputs.nixpkgs.follows = "nixpkgs";
     };
     flake-utils.url = "github:numtide/flake-utils";
+    rust-overlay = {
+      url = "github:oxalica/rust-overlay";
+      inputs = {
+        nixpkgs.follows = "nixpkgs";
+        flake-utils.follows = "flake-utils";
+      };
+    };
   };
 
   outputs = {
@@ -13,14 +20,17 @@
     nixpkgs,
     crane,
     flake-utils,
+    rust-overlay,
     ...
   }:
     flake-utils.lib.eachDefaultSystem (system: let
       pkgs = import nixpkgs {
         inherit system;
+        overlays = [(import rust-overlay)];
       };
 
-      craneLib = crane.lib.${system};
+      rustTarget = pkgs.rust-bin.fromRustupToolchainFile ./rust-toolchain.toml;
+      craneLib = (crane.mkLib pkgs).overrideToolchain rustTarget;
       git-view = craneLib.buildPackage {
         src = craneLib.cleanCargoSource (craneLib.path ./.);
         buildInputs = [] ++ pkgs.lib.optionals pkgs.stdenv.isDarwin [pkgs.libiconv];