anchor.diff:    mkScala = args: stdenv.mkDerivation rec {
       name = "scala-${args.version}";
       src = fetchurl {
  -      url = "http://www.scala-lang.org/files/archive/${name}.tgz";
  +      urls = [
  +        "http://www.scala-lang.org/files/archive/${name}.tgz"
  +        "http://downloads.typesafe.com/scala/${args.version}/${name}.tgz"
  +      ];
         inherit (args) sha256;
       };
       installPhase = ''
  
positive.code:       sha256 = "16ac935wydrxrvijv4ldnz4vl2xk8yb3yzb9bsi3nb9sic7fxl95";
      };
      "2.10" = scalaVersions."2.10.3";
      "2.11.0-M7" = {
        version = "2.11.0-M7";
        sha256 = "0rhc4rnz8vfdf5f72zlr79k5iavm2q8jyin7h7mzmipr0v1lvsyn";
      };
    };
  
  
negative.code: { pkgs ? import <nixpkgs> {} }:
  
  with pkgs;
  with lib;
  with builtins;
  
  