Remove toolchain.toml dependency

flake.nix

@@ -1,4 +1,3 @@
-# flake.nix
 {
   inputs = {
     nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
@@ -8,15 +7,20 @@
   outputs = { self, nixpkgs, rust-overlay, }:
     let
       system = "x86_64-linux";
+      rustVersion = "1.62.0";
+      rust = pkgs.rust-bin.stable.${rustVersion}.default.override {
+        extensions = [
+          "rust-src" # for rust-analyzer
+        ];
+      };
       pkgs = import nixpkgs {
         inherit system;
         overlays = [ rust-overlay.overlays.default ];
       };
-      toolchain = pkgs.rust-bin.fromRustupToolchainFile ./toolchain.toml;
     in {
       devShells.${system}.default = pkgs.mkShell {
-        packages = [ toolchain pkgs.rust-analyzer-unwrapped ];
-        RUST_SRC_PATH = "${toolchain}/lib/rustlib/src/rust/library";
+        buildInputs = [ rust ] ++ (with pkgs; [ rust-analyzer pkg-config ]);
+        RUST_BACKTRACE = 1;
       };
     };
 }

toolchain.toml

@@ -1,4 +0,0 @@
-[toolchain]
-channel = "nightly"
-components = [ "rustfmt", "rust-src", "rust-src" ]
-profile = "minimal"