anchor.diff:  else
   
   let param =
  -if OCamlVersionAtLeast "4.08" then rec {
  -  version = "8.06.7";
  -  src = fetchzip {
  -    url = "https://github.com/garrigue/labltk/archive/${version}.tar.gz";
  -    sha256 = "1cqnxjv2dvw9csiz4iqqyx6rck04jgylpglk8f69kgybf7k7xk2h";
  -  };
  -} else
  +  let mkNewParam = { version, sha256 }: {
  +    inherit version;
  +    src = fetchzip {
  +      url = "https://github.com/garrigue/labltk/archive/${version}.tar.gz";
  +      inherit sha256;
  +    };
  +  }; in
     let mkOldParam = { version, key, sha256 }: {
       src = fetchurl {
         url = "https://forge.ocamlcore.org/frs/download.php/${key}/labltk-${version}.tar.gz";
  
positive.code:     };
      inherit version;
    }; in
   {
    "4.04" = mkOldParam {
      version = "8.06.2";
      key = "1628";
  
negative.code:     version = "8.06.5";
      key = "1764";
      sha256 = "0wgx65y1wkgf22ihpqmspqfp95fqbj3pldhp1p3b1mi8rmc37zwj";
    };
    _8_06_7 = mkNewParam {
      version = "8.06.7";
      sha256 = "1cqnxjv2dvw9csiz4iqqyx6rck04jgylpglk8f69kgybf7k7xk2h";
    };
    "4.08" = _8_06_7;
    "4.09" = _8_06_7;
    "4.10" = mkNewParam {
      version = "8.06.8";
      sha256 = "0lfjc7lscq81ibqb3fcybdzs2r1i2xl7rsgi7linq46a0pcpkinw";
    };
  }.${builtins.substring 0 4 ocaml.version};
  in
  