anchor.diff:    };
   
     passthru = {
  -    compatibleCoqVersions = v: builtins.elem v [ "8.6" "8.7" ];
  +    compatibleCoqVersions = v: builtins.hasAttr v params;
     };
   }
  
positive.code:       rev = "V8.8+beta1";
        sha256 = "1ymxyrvjygscxkfj3qkq66skl3vdjhb670rzvsvgmwrjkrakjnfg";
      };
    }."${coq.coq-version}"
  ; in
  
  stdenv.mkDerivation rec {
  
negative.code: { stdenv, fetchFromGitHub, coq }:
  
  let params =
    {
      "8.6" = {
        rev = "v8.6.0";
  