anchor.diff:  
     grpc = buildFromGitHub {
       version = 2;
  -    rev = "0e6ec3a4501ee9ee2d023abe92e436fd04ed4081";
  +    rev = "3e1c91c1e0a72a34f68542bc029792b031835cbf";
       owner = "grpc";
       repo = "grpc-go";
  -    sha256 = "1ph5dpzgnhs7al22vq1npczjs6sypv3445rc1692nnizhlwfczcd";
  +    sha256 = "0zm4jf04gqdf4m97y0h3gz1fn0smmabfn6b3nhkhifazyfpwgzcf";
       goPackagePath = "google.golang.org/grpc";
       goPackageAliases = [ "github.com/grpc/grpc-go" ];
       propagatedBuildInputs = [ http2 net protobuf oauth2 glog ];
       excludedPackages = "\\(test\\|benchmark\\)";
       meta.useUnstable = true;
  -    date = "2016-09-06";
  +    date = "2016-09-12";
     };
   
     gucumber = buildFromGitHub {
  
positive.code:   };
  
    yaml_v2 = buildFromGitHub {
      version = 1;
      rev = "e4d366fc3c7938e2958e662b4258c7a89e1f0e3e";
      date = "2016-07-15";
      owner = "go-yaml";
      repo = "yaml";
      sha256 = "13dkg0x8ydrcc62w7j5sh6iq2wr79rqb31ks4saq5sllphr2xn7r";
      goPackagePath = "gopkg.in/yaml.v2";
    };
  
  
negative.code:   };
  
    go4 = buildFromGitHub {
      version = 2;
      date = "2016-09-11";
      rev = "e7a2449258501866491620d4f47472e6100ca551";
      owner = "camlistore";
      repo = "go4";
      sha256 = "097ll3m8wbcr5ivcfwa47khw721sj4sd1fqkzyl1iwviyw8ycssd";
      goPackagePath = "go4.org";
      goPackageAliases = [ "github.com/camlistore/go4" ];
      buildInputs = [
  