anchor.diff:  
     gocql = buildFromGitHub {
       version = 2;
  -    rev = "5d087d1f0cd04ad126a3b2642b041d8f4a750677";
  +    rev = "b6e5fc4b08a956657367e1ab9eb38e65a6ab6abe";
       owner  = "gocql";
       repo   = "gocql";
  -    sha256 = "1wbwsq2ig4hjr4fjs3kmbkq7pndrxp3qspxzj6qsi9gfi49v564n";
  +    sha256 = "13a1h0kfwahw99j13rkbqq5yixq7wlbywabn114bww9asbf8c50j";
       propagatedBuildInputs = [
         inf_v0
         snappy
         hailocab_go-hostpool
         net
       ];
  -    date = "2016-12-29";
  +    date = "2017-01-15";
     };
   
     gojsonpointer = buildFromGitHub {
  
positive.code: 
    copystructure = buildFromGitHub {
      version = 2;
      date = "2017-01-06";
      rev = "fa7e5b3642ee8042df11f4aa0cbbe73a0c38a983";
      owner = "mitchellh";
      repo = "copystructure";
      sha256 = "02yc1xbnz3fa0rsiqxh22k1lc3yq19d95mmwbb37aizri7bqagwq";
      propagatedBuildInputs = [ reflectwalk ];
    };
  
  
negative.code: 
    tools = buildFromGitHub {
      version = 2;
      rev = "608c3b098abba448c9e25b436e2c0e0c937311d6";
      date = "2017-01-15";
      owner = "golang";
      repo = "tools";
      sha256 = "1vdasp9pcfmdg6wxhnzgy37xj9qf34fxw60gqj8h7dlpnkh0qwrp";
      goPackagePath = "golang.org/x/tools";
      goPackageAliases = [ "code.google.com/p/go.tools" ];
  
  