anchor.diff:  
       src = fetchurl {
         url = "https://raw.githubusercontent.com/scalacenter/bloop/v${version}/etc/zsh/_bloop";
  -      sha256 = "09qq5888vaqlqan2jbs2qajz2c3ff13zj8r0x2pcxsqmvlqr02hp";
  +      sha256 = "1xzg0qfkjdmzm3mvg82mc4iia8cl7b6vbl8ng4ir2xsz00zjrlsq";
       };
   
       phases = [ "installPhase" ];
  
positive.code: 
        export COURSIER_CACHE=$(pwd)
        ${coursier}/bin/coursier bootstrap ch.epfl.scala:bloop-frontend_2.12:${version} \
          -r "bintray:scalameta/maven" \
          -r "bintray:scalacenter/releases" \
          -r "https://oss.sonatype.org/content/repositories/staging" \
          --deterministic \
          -f --main bloop.Server -o $out/bin/blp-server
      '';
      outputHashMode = "recursive";
      outputHashAlgo = "sha256";
      outputHash     = "1z33ip6hgfwiixm2gimz819p5cnxn1fmxb3ryyf77jzwsx7py718";
    };
  
    zsh = stdenv.mkDerivation {
  
negative.code: { stdenv, fetchurl, coursier,
   autoPatchelfHook, 
   lib, zlib }:
  
  let
    baseName = "bloop";
    version = "1.4.1";
  
    client = stdenv.mkDerivation {
      name = "${baseName}-client-${version}";
  
      nativeBuildInputs = [ autoPatchelfHook ] ;
      phases = [ "installPhase" "fixupPhase" ];
      buildInputs = [ stdenv.cc.cc.lib zlib] ;
  
      installPhase = ''
        mkdir -p $out/bin
   
        export COURSIER_CACHE=$(pwd)
        ${coursier}/bin/coursier install bloop:${version} \
                                 --repository "bintray:scalameta/maven" \
                                 --repository "bintray:scalacenter/releases" \
                                 --repository "https://oss.sonatype.org/content/repositories/staging" \
                                 --force \
                                 --install-dir $out
      '';
      
      outputHashMode = "recursive";
      outputHashAlgo = "sha256";
      outputHash     = "01hgv0j0a4v8iqi638rcqdirpa30jwfp7gh7dvsk32apx003ylvb";
    };
  
    server = stdenv.mkDerivation {
  