anchor.diff:    if stdenv.lib.versionAtLeast coq.coq-version "8.6" then
     {
       version = "1.7.0";
  -    sha256 = "05zgyi4wmasi1rcyn5jq42w0bi9713q9m8dl1fdgl66nmacixh39";
  +    sha256 = "0wnhj9nqpx2bw6n1l4i8jgrw3pjajvckvj3lr4vzjb3my2lbxdd1";
     }
     else if stdenv.lib.versionAtLeast coq.coq-version "8.5" then
     {
       version = "1.6.1";
  -    sha256 = "1j9ylggjzrxz1i2hdl2yhsvmvy5z6l4rprwx7604401080p5sgjw";
  +    sha256 = "1ilw6vm4dlsdv9cd7kmf0vfrh2kkzr45wrqr8m37miy0byzr4p9i";
     }
     else throw "No version of math-comp is available for Coq ${coq.coq-version}";
   
  
positive.code: { stdenv, fetchurl, coq, ncurses, which
  , graphviz, withDoc ? false
  }:
  
  
negative.code: stdenv.mkDerivation {
    name = "coq${coq.coq-version}-mathcomp-${param.version}";
  
    src = fetchFromGitHub {
      owner = "math-comp";
      repo = "math-comp";
      rev = "mathcomp-${param.version}";
      inherit (param) sha256;
    };
  
  