anchor.diff:  then
     buildDunePackage {
       inherit pname src meta;
  -    inherit (param) version useDune2 buildInputs nativeBuildInputs;
  +    inherit (param) version buildInputs nativeBuildInputs;
   
       strictDeps = true;
     }
  
positive.code: { lib, stdenv, fetchFromGitHub, buildDunePackage, ocaml, findlib, cppo }:
  
  let param =
    let v6_5 = {
      version = "6.5";
      sha256 = "sha256:0fwibah2hgllrnbdrmfqil5gr5raf6pb5h2zx6zs1h3d4ykvy8k8";
      useDune2 = true;
      nativeBuildInputs = [cppo];
      buildInputs = [cppo];
    }; in
  
negative.code:   "4.07" = {
      version = "5.1+4.06.0";
      sha256 = "1ww4cspdpgjjsgiv71s0im5yjkr3544x96wsq1vpdacq7dr7zwiw"; };
    "4.08" = v6_6;
    "4.09" = v6_6;
    "4.10" = v6_6;
    "4.11" = v6_6;
    "4.12" = v6_6;
    "4.13" = v6_6;
    "4.14" = v6_6;
  }.${ocaml.meta.branch};
  in
  
  