anchor.diff:  
     google-cloud-go = buildFromGitHub {
       version = 3;
  -    date = "2017-06-23";
  -    rev = "9d0d2cf2897dfcd18a86e1666038caf1c38e77f8";
  +    date = "2017-06-26";
  +    rev = "2cbf161fc57d9dda2921f3d7841e0b683fa09d3e";
       owner = "GoogleCloudPlatform";
       repo = "google-cloud-go";
  -    sha256 = "1d1mbrw953sw6gf1mnwhip8hp9pnbw3grjwb4v5134kx56zgcm9g";
  +    sha256 = "0g827xqvbkxyfzc6pb2dc5cdmsskp55smlw42m5js9rvvsp93z0z";
       goPackagePath = "cloud.google.com/go";
       goPackageAliases = [
         "google.golang.org/cloud"
  
positive.code: 
    sys = buildFromGitHub {
      version = 3;
      rev = "c23410a886927bab8ca5e80b08af6a56faeb330d";
      date = "2017-06-23";
      owner  = "golang";
      repo   = "sys";
      sha256 = "1vygh0fz6nww538hmlgdqxqvi20l966zm55hc0qb8wl2gbg87mgc";
      goPackagePath = "golang.org/x/sys";
    };
  
  
negative.code: 
    grpc = buildFromGitHub {
      version = 3;
      date = "2017-06-26";
      rev = "57ff3285cf4df537f41daa0a5fa283bdb5944e60";
      owner = "grpc";
      repo = "grpc-go";
      sha256 = "1az4k9llixi37n6qxvxzzxcz7784maznza561iqjmxcdyl2wsagz";
      goPackagePath = "google.golang.org/grpc";
      goPackageAliases = [
        "github.com/grpc/grpc-go"
  