anchor.diff:  
     tools = buildFromGitHub {
       version = 2;
  -    rev = "1dce95f761bfeb6fe2aa3c4e9ffdb261b69b3fc4";
  -    date = "2017-03-01";
  +    rev = "8ffd8eda92fbb57a42688bcd05e2481b813f88e8";
  +    date = "2017-03-04";
       owner = "golang";
       repo = "tools";
  -    sha256 = "1hwfay7fyzyr46467xpvw38ani6zwv4czh4hprgvmiy5nlz5wxsp";
  +    sha256 = "1zdmrqvpr8q67z7i0yp7vz4pa4y228cz5k3p70q2bw6hrpgj3s90";
       goPackagePath = "golang.org/x/tools";
       goPackageAliases = [ "code.google.com/p/go.tools" ];
   
  
positive.code:     version = 2;
      owner = "ncw";
      repo = "rclone";
      rev = "5fba9132071b8696cb9ae595f2bf700f2ec62403";
      sha256 = "008is871bv3y55arikqpi2pvwqy2y7gpik8x4yzn0n85hr90x58b";
      propagatedBuildInputs = [
        aws-sdk-go
        cobra
  
negative.code: 
    genproto = buildFromGitHub {
      version = 2;
      date = "2017-03-03";
      rev = "1e95789587db7d93ebbaa5eb65da17d3dbf8ab64";
      owner  = "google";
      repo   = "go-genproto";
      goPackagePath = "google.golang.org/genproto";
      sha256 = "1359q9ip6kfwc25fj43xb6blidgv3p4c805ddkqf7kfqxkzdd2ya";
      propagatedBuildInputs = [
        grpc
        net
  