anchor.diff:  
     tools = buildFromGitHub {
       version = 2;
  -    rev = "81478017b604f98ba7a7300ddf703b12b119c49c";
  -    date = "2017-04-25";
  +    rev = "9a6c6fca12efdd355f948c5b748b8b48edbb4ef0";
  +    date = "2017-04-26";
       owner = "golang";
       repo = "tools";
  -    sha256 = "08di73mci5kswbv1lpxf7xds2wf7xl1b0im7h0yvgzvv1jdkqwnd";
  +    sha256 = "087bv7ll4kx8amcgzx3w6vjq6w0mzllzvqx74zxpa9w4x6iyigzz";
       goPackagePath = "golang.org/x/tools";
       goPackageAliases = [ "code.google.com/p/go.tools" ];
   
  
positive.code: 
    crypto = buildFromGitHub {
      version = 2;
      rev = "5f995c0d1c72642b4845a718a648d17fce6ed6fa";
      date = "2017-04-25";
      owner    = "golang";
      repo     = "crypto";
      sha256 = "1xp4l67rc36vil56kqpcr5i31xkpnjngwyfkmbbpsdsk0f9jiasl";
      goPackagePath = "golang.org/x/crypto";
      goPackageAliases = [
        "code.google.com/p/go.crypto"
  
negative.code:     version = 2;
      owner = "minio";
      repo = "minio-go";
      rev = "5297a818b482fa329b3dc1a3926e3c4c6fb5d459";
      sha256 = "071g2y3pfrvvzgh1ac5zx5q4zvm0y1ka0cpy43f1q7rn758l476a";
      meta.useUnstable = true;
      date = "2017-04-26";
    };
  
    missinggo = buildFromGitHub {
  