anchor.diff:    grpc = buildFromGitHub {
       version = 2;
       date = "2017-02-10";
  -    rev = "bd3ebf8e9eba3fbe76f0f7b3ace57c7099a071aa";
  +    rev = "4acc9108c18937815db3306a66990869d22aa980";
       owner = "grpc";
       repo = "grpc-go";
  -    sha256 = "088csdykwgagp3ki934wq6k39shh8chdq795yic1cch61psg21fj";
  +    sha256 = "01ldgiz3g6gbvp43ca05m5iz5yb4a69z7n2c338b3vkhdhzlmll7";
       goPackagePath = "google.golang.org/grpc";
       goPackageAliases = [
         "github.com/grpc/grpc-go"
  
positive.code: 
    aws-sdk-go = buildFromGitHub {
      version = 2;
      rev = "v1.6.20";
      owner  = "aws";
      repo   = "aws-sdk-go";
      sha256 = "0w1i6cqlp778g8xwixlm5g907nz7z8f4ifsmv85kjcr0ni638yyw";
      excludedPackages = "\\(awstesting\\|example\\)";
      buildInputs = [
        tools
  
negative.code:     version = 2;
      owner = "rfjakob";
      repo = "eme";
      rev = "fd00240838d2e0fe6b2c58bf5b27db843d828ad5";
      date = "2017-02-05";
      sha256 = "1zykkxsc6606iwrsnvr7kvz8f44snspm35ym2d0cyx45kvbd5195";
      meta.useUnstable = true;
    };
  
  