{ nixpkgs ? import <nixpkgs> { }}:
let
  # If you set hash to an empty string, you'll get
  # an error with the correct hash.
  pinnedPkgs = nixpkgs.fetchFromGitHub {
    owner  = "NixOS";
    repo   = "nixpkgs";
    rev    = "4ecab3273592f27479a583fb6d975d4aba3486fe";
    sha256 = "btHN1czJ6rzteeCuE/PNrdssqYD2nIA4w48miQAFloM=";
  };
  pkgs = import pinnedPkgs {};

in pkgs.mkShell {
  buildInputs = with pkgs; [
    cargo
    rustc
    rustfmt
    rust-analyzer
    wasm-pack
   ];
}