anchor.diff:      version = 2;
       owner = "coreos";
       repo = "etcd";
  -    date = "2017-04-20";
  -    rev = "633a4e6b5288ecdbacbb8360c8f202d7c9fa2dc6";
  -    sha256 = "1w8idyajlzpa7xc8bl9kpwggpnjygawgfx07rfgyhq6vr2yy08g7";
  +    date = "2017-04-21";
  +    rev = "a9087ee659e58f26de72c4809ddabd8f58b4a97a";
  +    sha256 = "1qjm9blr6lhbbaxwrahb434a4s6kjda1c8c1p1s8nqj2hlz6jsm4";
       buildInputs = [
         bolt
         btree
  
positive.code: 
    teleport = buildFromGitHub {
      version = 2;
      rev = "v2.0.3";
      owner = "gravitational";
      repo = "teleport";
      sha256 = "0mbyipaml4kqhharyvsm2dnf91r7yfmfqswh92zh0c62h80qssd9";
      buildInputs = [
        aws-sdk-go
        bolt
  
negative.code: 
    sys = buildFromGitHub {
      version = 2;
      rev = "ea9bcade75cb975a0b9738936568ab388b845617";
      date = "2017-04-21";
      owner  = "golang";
      repo   = "sys";
      sha256 = "0hfdvdd4sics8skwncn4f7kk677w9qa3azq8d890p4i1k5xr8l2x";
      goPackagePath = "golang.org/x/sys";
      goPackageAliases = [
        "github.com/golang/sys"
  