anchor.diff:  
     yaml_v2 = buildFromGitHub {
       version = 2;
  -    rev = "31c299268d302dd0aa9a0dcf765a3d58971ac83f";
  -    date = "2016-09-12";
  +    rev = "a5b47d31c556af34a302ce5d659e6fea44d90de0";
  +    date = "2016-09-28";
       owner = "go-yaml";
       repo = "yaml";
  -    sha256 = "0k2jasi5fqz114iqy0z5dwg77gf4zch14vh59njjynh1gn6gyrzz";
  +    sha256 = "1aggcvz2pw5fn7mpw533iq448s1dzfmv6jg5mqi4vavzn351zjqf";
       goPackagePath = "gopkg.in/yaml.v2";
     };
   
  
positive.code: 
    go-multiaddr = buildFromGitHub {
      version = 2;
      rev = "197f65382f3b21e04b5ad4608274ec497dd49e4d";
      date = "2016-09-19";
      owner  = "multiformats";
      repo   = "go-multiaddr";
      sha256 = "15d9za3yrxhs63zdnd8d058bqws707ci2a1ryy1i1hr2jdj7dlvv";
      goPackageAliases = [ "github.com/jbenet/go-multiaddr" ];
      propagatedBuildInputs = [
        go-multihash
  
negative.code: 
    gcloud-golang = buildFromGitHub {
      version = 2;
      date = "2016-09-28";
      rev = "debdc0ca0113dd546ebebeb2000c9d938059f41d";
      owner = "GoogleCloudPlatform";
      repo = "gcloud-golang";
      sha256 = "1635f1gvjn22cb0z1jj175kjfv3mz6jnz49sgyrf15npsfqc72vc";
      goPackagePath = "cloud.google.com/go";
      goPackageAliases = [
        "google.golang.org/cloud"
  