anchor.diff:  
     sys = buildFromGitHub {
       version = 2;
  -    rev = "8f0908ab3b2457e2e15403d3697c9ef5cb4b57a9";
  -    date = "2016-09-14";
  +    rev = "8d1157a435470616f975ff9bb013bea8d0962067";
  +    date = "2016-10-06";
       owner  = "golang";
       repo   = "sys";
  -    sha256 = "0kk2za4grwh0kr6v5mvnr90pilqbp1x0rbrnfyz02y5p5blprhyl";
  +    sha256 = "1ahd3c0bi2ljcpz36b440glmq9x7x269cf8y8ddczg2yk1rm675j";
       goPackagePath = "golang.org/x/sys";
       goPackageAliases = [
         "github.com/golang/sys"
  
positive.code: 
    btree = buildFromGitHub {
      version = 2;
      rev = "7364763242911ab6d418d2722e237194938ebad0";
      owner  = "google";
      repo   = "btree";
      sha256 = "16cnqa77msnikx3h18nbny23csr2mbai050aa78niznv0kyzg3lp";
      date = "2016-09-23";
    };
  
    bufio_v1 = buildFromGitHub {
  
negative.code: 
    genproto = buildFromGitHub {
      version = 2;
      date = "2016-10-07";
      rev = "9359a8d303c45e3212571b77610f1cefb0c6f3eb";
      owner  = "google";
      repo   = "go-genproto";
      goPackagePath = "google.golang.org/genproto";
      sha256 = "1acsy7kh08pxxq97ss5410vd46gns7hrigb0qmma1g3zsmyqmlcl";
      propagatedBuildInputs = [
        grpc
        net
  