{
  compiler ? "ghc865",
  withHIE ? false
}:

let
  # pin all-hies for getting the language server
  all-hies = fetchTarball {
    url = "https://github.com/infinisil/all-hies/tarball/b8fb659620b99b4a393922abaa03a1695e2ca64d";
    sha256 = "sha256:0br6wsqpfk1lzz90f7zw439w1ir2p54268qilw9l2pk6yz7ganfx";
  };
  pkgs = import (
    builtins.fetchGit {
      name = "nixpkgs-pinned";
      url = https://github.com/NixOS/nixpkgs/;
      ref = "refs/heads/release-20.03";
      #rev = "de3780b937d2984f9b5e20d191f23be4f857b3aa";
      rev = "faf5bdea5d9f0f9de26deaa7e864cdcd3b15b4e8";
    }) {
      # Pass no config for purity
          config = {};
              overlays = [
                      (import all-hies {}).overlay
                          ];
    };
  hp = pkgs.haskell.packages."${compiler}";
  src = pkgs.nix-gitignore.gitignoreSource [] ./.;
  drv = hp.callCabal2nix "Hash2Pub" "${src}/Hash2Pub.cabal" {};
in
{
  my_project = drv;
  shell = hp.shellFor {
    withHoogle = true;
    packages = p: [ drv ];
    buildInputs = with hp;
      [
        haddock
        cabal-install
        hlint
        stylish-haskell
        pkgs.python3Packages.asn1ate
      ]
      ++ (if withHIE then [ hie ] else []);
  };
}