anchor.diff:  let
   
     inherit (releng_pkgs.lib) mkTaskclusterHook mkPython fromRequirementsFile filterSource mkRustPlatform;
  -  inherit (releng_pkgs.pkgs) writeScript makeWrapper fetchurl mercurial cacert rustStable ;
  +  inherit (releng_pkgs.pkgs) writeScript makeWrapper fetchurl cacert rustStable ;
     inherit (releng_pkgs.pkgs.stdenv) mkDerivation;
     inherit (releng_pkgs.pkgs.lib) fileContents optional licenses;
  -  inherit (releng_pkgs.tools) pypi2nix;
  +  inherit (releng_pkgs.tools) pypi2nix mercurial ;
   
     python = import ./requirements.nix { inherit (releng_pkgs) pkgs; };
     rustPlatform = mkRustPlatform {};
     name = "mozilla-shipit-code-coverage";
     dirname = "shipit_code_coverage";
  -
  -  robustcheckout = mkDerivation {
  -    name = "robustcheckout";
  -    src = fetchurl {
  -      url = "https://hg.mozilla.org/hgcustom/version-control-tools/archive/1a8415be17e8.tar.bz2";
  -      sha256 = "005n7ar8cn7162s1qx970x1aabv263zp7mxm38byxc23nzym37kn";
  -    };
  -    installPhase = ''
  -      mkdir -p $out
  -      cp -rf hgext/robustcheckout $out
  -    '';
  -    doCheck = false;
  -    buildInputs = [];
  -    propagatedBuildInputs = [ ];
  -    meta = {
  -      homepage = "https://hg.mozilla.org/hgcustom/version-control-tools";
  -      license = licenses.mit;
  -      description = "Mozilla Version Control Tools: robustcheckout";
  -    };
  -  };
  -
  -  mercurial' = mercurial.overrideDerivation (old: {
  -    postInstall = old.postInstall + ''
  -      cat > $out/etc/mercurial/hgrc <<EOF
  -[web]
  -cacerts = ${cacert}/etc/ssl/certs/ca-bundle.crt
  -
  -[extensions]
  -purge =
  -robustcheckout = ${robustcheckout}/robustcheckout/__init__.py
  -EOF
  -    '';
  -  });
   
     # Marco grcov
     grcov = rustPlatform.buildRustPackage rec {
  
positive.code:       ln -s ${releng_pkgs.pkgs.lcov}/bin/lcov $out/bin
        ln -s ${rustStable.rustc}/bin/rustc $out/bin
        ln -s ${rustStable.cargo}/bin/cargo $out/bin
      '';
      shellHook = ''
        export PATH="${mercurial'}/bin:$PATH"
      '';
      passthru = {
        taskclusterHooks = {
  
negative.code:         rustStable.rustc
          rustStable.cargo
          grcov
          releng_pkgs.gecko-env
        ];
      postInstall = ''
        mkdir -p $out/tmp
        mkdir -p $out/bin
        ln -s ${mercurial}/bin/hg $out/bin
  
        # Needed by grcov runtime
        ln -s ${releng_pkgs.pkgs.gcc}/bin/gcc $out/bin
  