put the whole rust toolchain into one package so Rider can handle it

shell.nix

@@ -1,16 +1,24 @@
-{pkgs ? import <nixpkgs> {}}:
-pkgs.mkShell {
-  nativeBuildInputs = with pkgs.buildPackages; [
-    rustc cargo gcc rustfmt clippy
+{pkgs ? import <nixpkgs> {}}: let
+  rust-toolchain = pkgs.symlinkJoin {
+    name = "rust-toolchain";
+    paths = with pkgs; [rustc cargo rustPlatform.rustcSrc rustfmt clippy];
+  };
+in
+  pkgs.mkShell {
+    nativeBuildInputs = with pkgs.buildPackages; [
+      rust-toolchain
 
-    pkg-config
-    xe
-    lzma
-    cargo-tarpaulin
-    gnumake
+      pkg-config
+      xe
+      lzma
 
-    # dotnet-sdk_8
-  ];
+      cargo-tarpaulin
 
-  RUST_SRC_PATH = "${pkgs.rust.packages.stable.rustPlatform.rustLibSrc}";
-}
+      gcc
+      gnumake
+
+      # dotnet-sdk_8
+    ];
+
+    RUST_SRC_PATH = "${pkgs.rust.packages.stable.rustPlatform.rustLibSrc}";
+  }