config.nix

{ pkgs }:

{
  allowBroken = true;
  allowUnfree = true;

  haskellPackageOverrides = self : super : (let inherit (pkgs.haskell-ng) lib; in {
    shake       = lib.dontCheck super.shake;
    zip-archive = lib.dontCheck super.zip-archive;
  });

  packageOverrides = pkgs : rec {
    haskellEnv = pkgs.haskellngPackages.ghcWithPackages (p : with p; [
      ghc cabal2nix cabal-install alex happy
    ]);
  }
}