anchor.diff:      "8.8" = {
         version = "1.0";
         rev = "v1.0-8.8";
  -      sha256 = "129rxsdsf88vjcw0xhm74yax1hmnk6f8n9ksg0hcyyjq1ijddiwa";
  +      sha256 = "0dd7zd5j2sv5cw3mfwg33ss2vcj634q3qykakc41sv7f3rfgqfnn";
       };
  -
  -  }."${coq.coq-version}"
  -; in
  +  };
  +  param = params."${coq.coq-version}";
  +in
   
   stdenv.mkDerivation rec {
   
  
positive.code: { stdenv, fetchFromGitHub, coq }:
  
  let param =
    {
      "8.6" = {
        version = "1.0";
        rev = "v1.0";
  
negative.code:   };
  
    passthru = {
      compatibleCoqVersions = v: builtins.hasAttr v params;
    };
  
  }
  