anchor.diff:    parse_trans = fetchHex {
       pkg = "parse_trans";
       version = "3.3.0";
  -    sha256 = "17ef63abde837ad30680ea7f857dd9e7ced9476cdd7b0394432af4bfc241b960";
  +    sha256 = "0q5r871bzx1a8fa06yyxdi3xkkp7v5yqazzah03d6yl3vsmn7vqp";
     };
   
   in
  -stdenv.mkDerivation {
  -  name = "rebar3-${version}";
  +stdenv.mkDerivation rec {
  +  pname = "rebar3";
     inherit version erlang;
   
  -  src = fetchurl {
  -    url = "https://github.com/rebar/rebar3/archive/${version}.tar.gz";
  -    sha256 = "1n6287av29ws3bvjxxmw8s2j8avwich4ccisnnrnypfbm1khlcxp";
  +  src = fetchFromGitHub {
  +    owner = "rebar";
  +    repo = pname;
  +    rev = version;
  +    sha256 = "1p34kfkrdmsixg95ad76rifjwfh484vp688lxsjaxg0kf2xjr2d2";
     };
   
     inherit bootstrapper;
  
positive.code: 
    meta = {
      homepage = https://github.com/rebar/rebar3;
      description = "rebar 3 is an Erlang build tool that makes it easy to compile and test Erlang applications, port drivers and releases";
  
      longDescription = ''
        rebar is a self-contained Erlang script, so it's easy to distribute or
  
negative.code: { stdenv, fetchFromGitHub,
    fetchHex, erlang,
    tree, hexRegistrySnapshot }:
  
  let
    version = "3.10.0";
  
    bootstrapper = ./rebar3-nix-bootstrap;
  
  