diff --git a/flake.nix b/flake.nix
index a670319..2c29ffa 100644
--- a/flake.nix
+++ b/flake.nix
@@ -14,11 +14,18 @@
     flake-utils.lib.eachDefaultSystem (system:
       let
         pkgs = nixpkgs.legacyPackages.${system};
+
+        cargoBuildInputs = with pkgs; lib.optionals stdenv.isDarwin [
+          darwin.apple_sdk.frameworks.CoreServices
+        ];
+
         rustlings =
           pkgs.rustPlatform.buildRustPackage {
             name = "rustlings";
             version = "5.3.0";
 
+            buildInputs = cargoBuildInputs;
+
             src = with pkgs.lib; cleanSourceWith {
               src = self;
               # a function that returns a bool determining if the path should be included in the cleaned source
@@ -42,12 +49,16 @@
       in
       {
         devShell = pkgs.mkShell {
+          RUST_SRC_PATH = "${pkgs.rust.packages.stable.rustPlatform.rustLibSrc}";
+
           buildInputs = with pkgs; [
             cargo
             rustc
             rust-analyzer
             rustlings
-          ];
+            rustfmt
+            clippy
+          ] ++ cargoBuildInputs;
         };
       });
 }
diff --git a/src/project.rs b/src/project.rs
index 0df00b9..a6e3acf 100644
--- a/src/project.rs
+++ b/src/project.rs
@@ -1,5 +1,6 @@
 use glob::glob;
 use serde::{Deserialize, Serialize};
+use std::env;
 use std::error::Error;
 use std::process::Command;
 
@@ -64,6 +65,12 @@ impl RustAnalyzerProject {
 
     /// Use `rustc` to determine the default toolchain
     pub fn get_sysroot_src(&mut self) -> Result<(), Box<dyn Error>> {
+        // check if RUST_SRC_PATH is set
+        if let Ok(path) = env::var("RUST_SRC_PATH") {
+            self.sysroot_src = path;
+            return Ok(());
+        }
+
         let toolchain = Command::new("rustc")
             .arg("--print")
             .arg("sysroot")