anchor.diff:  
     text = buildFromGitHub {
       version = 2;
  -    rev = "d680ca3ed853995402af43b866311167281bdc20";
  -    date = "2017-03-01";
  +    rev = "f28f36722d5ef2f9655ad3de1f248e3e52ad5ebd";
  +    date = "2017-03-03";
       owner = "golang";
       repo = "text";
  -    sha256 = "041inc6ahf5bbsx04nbbm6yd7y90gmc432bdzydbzfdb4dj3phb9";
  +    sha256 = "1jvchi8df0r92df7r7lvkf25hpbrlawmfgbs49mnwnq0411nq2f4";
       goPackagePath = "golang.org/x/text";
       goPackageAliases = [ "github.com/golang/text" ];
       excludedPackages = "cmd";
  
positive.code: 
    genproto = buildFromGitHub {
      version = 2;
      date = "2017-02-14";
      rev = "dee11a626cb8e7ff045ac9413dcd8a92e72f5863";
      owner  = "google";
      repo   = "go-genproto";
      goPackagePath = "google.golang.org/genproto";
      sha256 = "1zfbwqizh9asvq6qbhpbjpn2jsfx8kf04pc3g67qzb3ff0hilv05";
      propagatedBuildInputs = [
        grpc
        net
  
negative.code: 
    swift = buildFromGitHub {
      version = 2;
      rev = "b6350f23a6ed2cad7d3697d0a7e0534f6d15e66d";
      owner  = "ncw";
      repo   = "swift";
      sha256 = "1djga80j0hcz8db7wyjsxzilgah5lsv1dnm3k29lr2ac29g44w2l";
      date = "2017-03-03";
    };
  
    anacrolix_sync = buildFromGitHub {
  