diff --git a/flake.nix b/flake.nix
index b5a7705..3036071 100644
--- a/flake.nix
+++ b/flake.nix
@@ -27,9 +27,13 @@
         (pkgs: {
           default = import ./shell.nix {
             inherit pkgs;
-            additionalBuildInputs = [
-              (pkgs.rust-bin.selectLatestNightlyWith (toolchain: toolchain.default))
-            ];
+            additionalBuildInputs =
+              let latestNightlyWith = pkgs.rust-bin.selectLatestNightlyWith;
+              in [
+                (latestNightlyWith (toolchain: toolchain.default.override {
+                  extensions = [ "rust-src" ];
+                }))
+              ];
           };
         });
     };