anchor.diff:  
   stdenv.mkDerivation ((builtins.removeAttrs attrs ["source"]) // {
     inherit ruby;
  -  inherit doCheck;
     inherit dontBuild;
     inherit dontStrip;
     inherit type;
  
positive.code:     rubyName = builtins.parseDrvName ruby.name;
    in "${rubyName.name}${rubyName.version}-")
  , buildInputs ? []
  , doCheck ? false
  , meta ? {}
  , patches ? []
  , gemPath ? []
  
negative.code:   name = attrs.name or "${namePrefix}${gemName}-${version}";
  
    inherit src;
  
    unpackPhase = attrs.unpackPhase or ''
      runHook preUnpack
  