Troubleshooting broken stripe-haskell in <nixpkgs>

buildHaskell.nix

{ pkgs, ... }:

{
  # Build a Haskell executable. This assumes a project directory with a
  # top-level Main.hs. It also applies a few commonly used language extensions.
  # Here is an overview of the arguments:
  # - `name`: You can find the result at ./result/$name
  # - `srcs`: Will be passed to `srcs` field of `pkgs.stdenv.mkDerivation`.
  # - `deps`: A function that accepts `hpkgs` and returns a list of Haskell
  #   dependencies.
  program = { name, srcs, deps, ghcExtensions }: let
    ghc = pkgs.haskellPackages.ghcWithPackages (hpkgs: deps hpkgs);
  in pkgs.stdenv.mkDerivation {
    name = name;
    buildInputs = [];
    srcs = srcs;
    buildPhase = ''
      ${ghc}/bin/ghc -Wall Main.hs ${pkgs.lib.concatMapStrings (x: "-X${x} ") ghcExtensions}
    '';
    installPhase = ''
      mkdir -p $out && mv Main $out/${name}
    '';
  };
}

stripe-haskell.nix

let
  briefcase = import /home/wpcarro/briefcase {};
  pkgs = briefcase.third_party.pkgs;
  stripe-src = pkgs.fetchFromGitHub {
    owner = "dmjio";
    repo = "stripe";
    rev = "4da0eb9f0d7fd05027108d95766eed10174014fc";
    sha256 = "1pjpx519yf96y5gb155lk6yaljbppjndkb4507xyl8qlblf4dn5a";
  };
  stripe-pkgs = import stripe-src { nixpkgs = pkgs; };
in briefcase.buildHaskell.program {
  name = "server";
  srcs = builtins.path {
    path = ./.;
    name = "LearnPianoChords-server-src";
  };
  ghcExtensions = [
    "OverloadedStrings"
    "NoImplicitPrelude"
    "RecordWildCards"
    "TypeApplications"
  ];
  deps = hpkgs: with hpkgs; [
    servant-server
    aeson
    wai-cors
    warp
    jwt
    unordered-containers
    base64
    http-conduit
    rio
    envy
    stripe-pkgs.stripe-haskell
  ];
}