anchor.diff:  
     rcrowley_go-metrics = buildFromGitHub {
       version = 2;
  -    rev = "b71dba47c7bf0374dfe3b67da7b5b702fa160a15";
  -    date = "2016-09-14";
  +    rev = "ab2277b1c5d15c3cba104e9cbddbdfc622df5ad8";
  +    date = "2016-09-21";
       owner = "rcrowley";
       repo = "go-metrics";
  -    sha256 = "1vvf914v8nshlv26mm498bj7qf93fgbjq6jc9sag27y7cl4k5mml";
  +    sha256 = "0y51jzdnvpl0iab7wqvbrkw6wnrygkfcikfwwh95pnik7m6rwlnx";
       propagatedBuildInputs = [ stathat ];
     };
   
  
positive.code: 
    sys = buildFromGitHub {
      version = 2;
      rev = "30de6d19a3bd89a5f38ae4028e23aaa5582648af";
      date = "2016-09-07";
      owner  = "golang";
      repo   = "sys";
      sha256 = "1a1j8cycykcd91h22rp0bk6zjy9nln2qpxiggpjcpd3szl9k99zv";
      goPackagePath = "golang.org/x/sys";
      goPackageAliases = [
        "github.com/golang/sys"
  
negative.code: 
    maxminddb-golang = buildFromGitHub {
      version = 2;
      date = "2016-09-19";
      rev = "2af0544f8e032bc7a363e897fbd9c6ed4884a1d6";
      owner  = "oschwald";
      repo   = "maxminddb-golang";
      sha256 = "0swgb6xgkf995qvr0zk66y2m5h3p6amcb0k9j52afkvj3yxrx8am";
      propagatedBuildInputs = [
        sys
      ];
  