anchor.diff:  
     uuid = buildFromGitHub {
       rev = "cccd189d45f7ac3368a0d127efb7f4d08ae0b655";
  -    date = "2015-08-24";
  +    version = "2015-08-24";
       owner = "pborman";
       repo = "uuid";
       sha256 = "0hswk9ihv3js5blp9pk2bpig64zkmyp5p1zhmgydfhb0dr2w8iad";
  
positive.code: 
    xdr = buildFromGitHub {
      rev    = "e467b5aeb65ca8516fb3925c84991bf1d7cc935e";
      date   = "2015-04-08";
      owner  = "calmh";
      repo   = "xdr";
      sha256 = "1bi4b2xkjzcr0vq1wxz14i9943k71sj092dam0gdmr9yvdrg0nra";
  
negative.code: 
    segment = buildFromGitHub {
      rev    = "db70c57796cc8c310613541dfade3dce627d09c7";
      version = "2016-01-05";
      owner  = "blevesearch";
      repo   = "segment";
      sha256 = "09xfdlcc6bsrr5grxp6fgnw9p4cf6jc0wwa9049fd1l0zmhj2m1g";
  