diff --git a/shell.nix b/shell.nix
index 6505d05247b12142bbb541554b664be9c8e5fadc..419f87e78520a93ecef2c939d7eddd2975818327 100644
--- a/shell.nix
+++ b/shell.nix
@@ -1,10 +1,10 @@
 let
-  pkgs = import (builtins.fetchTarball {
+  pinnedPkgs = import (builtins.fetchTarball {
     url = "https://github.com/NixOS/nixpkgs/archive/3c83ad6ac13b67101cc3e2e07781963a010c1624.tar.gz";
     sha256 = "0cdq342wrkvkyccygpp1gvwp7hhqg68hljjwld4vjixm901ayy14";
   }) {};
 in
-{ pkgs ? pkgs }:
+{ pkgs ? pinnedPkgs }:
 pkgs.mkShell {
   buildInputs = [
     pkgs.stack