anchor.diff:    };
   
     mafmt = buildFromGitHub {
  -    version = 2;
  -    date = "2017-03-24";
  -    rev = "15300f9d3a2d71db61951a8705d5ea8878764837";
  +    version = 3;
  +    date = "2017-07-11";
  +    rev = "8eaabeb0013fb995358b239e04394c27acaf38a2";
       owner = "whyrusleeping";
       repo = "mafmt";
  -    sha256 = "1kz254lswq71qf5107abrq8zz8hybkig5nn1ayygkd1fdfhq7grs";
  +    sha256 = "1k0r3zdv730r33p0gj2yjvmqscn44gzgla6ivqdc0dvk8wpl6z5g";
       propagatedBuildInputs = [
         go-multiaddr
       ];
  
positive.code:     version = 3;
      owner = "klauspost";
      repo = "reedsolomon";
      date = "2017-06-20";
      rev = "18d548df635f0d2c5c0e6bfc500d425ba1859403";
      sha256 = "0cswmg7hr9b29ir1wvz2vwmn19xn4yyrinm29bzylw8gx0m6bvwb";
      propagatedBuildInputs = [
        cpuid
      ];
  
negative.code: 
    genproto = buildFromGitHub {
      version = 3;
      date = "2017-07-11";
      rev = "b0a3dcfcd1a9bd48e63634bd8802960804cf8315";
      owner  = "google";
      repo   = "go-genproto";
      goPackagePath = "google.golang.org/genproto";
      sha256 = "0vrd4hfbc8m5w5ilvbyllr414i28v17xwc0xqcnqzgg56jmb9jyw";
      propagatedBuildInputs = [
        grpc
        net
  