with import <nixpkgs> {};
let src = fetchFromGitHub {
      owner  = "mozilla";
      repo   = "nixpkgs-mozilla";
      rev    = "e912ed483e980dfb4666ae0ed17845c4220e5e7c";
      sha256 = "08fvzb8w80bkkabc1iyhzd15f4sm7ra10jn32kfch5klgl0gj3j3";
   };
   moz_overlay = import (builtins.fetchTarball https://github.com/mozilla/nixpkgs-mozilla/archive/master.tar.gz);
   NIGHTLY_DATE="2020-09-15";
   nixpkgs = import <nixpkgs> { overlays = [ moz_overlay ]; };
   rustNightly = (nixpkgs.rustChannelOf { date = "${NIGHTLY_DATE}"; channel = "nightly"; }).rust.override {
     extensions = [
       "clippy-preview"
       "rustfmt-preview"
     ];
   };
in
with import "${src.out}/rust-overlay.nix" pkgs pkgs;
stdenv.mkDerivation {
  name = "rust-env";
  buildInputs = [
    # Note: to use use stable, just replace `nightly` with `stable`
    rustNightly

    # Add some extra dependencies from `pkgs`
    openssl
    zlib
    pkgconfig openssl binutils-unwrapped
    protobuf
    cargo-udeps
  ] ++ stdenv.lib.optionals stdenv.isDarwin [
        darwin.apple_sdk.frameworks.Security
      ];

  # Set Environment Variables
  RUST_BACKTRACE  = 1;
  LD_LIBRARY_PATH = "${zlib}/lib";
  PROTOC          = "${protobuf}/bin/protoc";
  PROTOC_INCLUDE  = "${protobuf}/include";

   shellHook = ''
      export PATH="$PATH:./target/debug"
    '';
}