anchor.diff:  
     tools = buildFromGitHub {
       version = 2;
  -    rev = "be0fcc31ae2332374e800dfff29b721c585b35df";
  -    date = "2016-11-04";
  +    rev = "8e779ee0a4509783f6940db32d1a4e8df910cc8b";
  +    date = "2017-02-14";
       owner = "golang";
       repo = "tools";
  -    sha256 = "1s8hnb21bni706hqbyfdk1q32axzjlg2l4rrhrzl0aqnfrfxzkr0";
  +    sha256 = "1pnz3ivbacbdj7w8jvayx22iiicmzx6hmbn6dygdqyp34blq2nvy";
       goPackagePath = "golang.org/x/tools";
       goPackageAliases = [ "code.google.com/p/go.tools" ];
   
  
positive.code: 
    procfs = buildFromGitHub {
      version = 2;
      rev = "a59ae619c824360be3641ceb5a456ff13dd58be6";
      date = "2017-02-14";
      owner  = "prometheus";
      repo   = "procfs";
      sha256 = "0m7bjxxsvp4d880sdc8x7bz4q6r5rfd6vm37qqzjqg16z918bdm4";
    };
  
    properties = buildFromGitHub {
  
negative.code:     version = 2;
      owner = "ncw";
      repo = "rclone";
      rev = "69a15ae1739e9bd8b92f5571e0a625f892ef76ec";
      sha256 = "1as8zfj038dr7vpg7114mci84xnj6lh5vx21l34ljahff2av2p29";
      propagatedBuildInputs = [
        aws-sdk-go
        cobra
  