diff --git a/shell.nix b/shell.nix
index d2dc1e4..0c43c99 100644
--- a/shell.nix
+++ b/shell.nix
@@ -1,8 +1,5 @@
 with import <nixpkgs> {};
-let
-  ginsim = callPackage ./ginsim.nix {};
-in
 stdenv.mkDerivation {
   name = "GINsim-shell";
-  buildInputs = [ ginsim ];
+  buildInputs = [ (callPackage ./ginsim.nix {}) ];
 }