anchor.diff:  
     crypto = buildFromGitHub {
       version = 2;
  -    rev = "dc137beb6cce2043eb6b5f223ab8bf51c32459f4";
  -    date = "2017-01-30";
  +    rev = "bed12803fa9663d7aa2c2346b0c634ad2dcd43b7";
  +    date = "2017-02-01";
       owner    = "golang";
       repo     = "crypto";
  -    sha256 = "1ls1sflzyiml91xbk4nwwcxy8m2md3qq4xi4lf9frw9gq6656swh";
  +    sha256 = "0wa0bdrlrh6kvzjmdwlv1d5bvwym7iizm50hhhwl6w32s0xik4rg";
       goPackagePath = "golang.org/x/crypto";
       goPackageAliases = [
         "code.google.com/p/go.crypto"
  
positive.code:       testify
      ];
      meta.useUnstable = true;
      date = "2017-01-30";
    };
  
    cupcake_rdb = buildFromGitHub {
  
negative.code: 
    circonus-gometrics = buildFromGitHub {
      version = 2;
      date = "2017-02-01";
      rev = "fb2909576d0526b70e3efa0ef10737b92f57f15a";
      owner  = "circonus-labs";
      repo   = "circonus-gometrics";
      sha256 = "1hdgh4rfsss60x6ml8iqzp5byn2lm4v7zni9jj2zjwdzzd1b0f8b";
      propagatedBuildInputs = [
        circonusllhist
        go-retryablehttp
  