anchor.diff:      pname = "with-editor";
       version = magit.version;
       src = magit.src;
  -    packageRequires = [ dash ];
  +    packageRequires = [ async dash ];
       fileSpecs = [ "Documentation/with-editor.texi" "lisp/with-editor.el" ];
       meta = { license = gpl3Plus; };
     };
  
positive.code:       owner  = "ocaml";
        repo   = pname;
        rev    = version;
        sha256 = "1j2smhqrwy0zydhbyjkpnwzq05fgfa85kc0d9kzwq0mppdndspp4";
      };
      packageRequires = [ caml ];
      meta = { license = gpl3Plus; };
  
negative.code: 
    async = melpaBuild rec {
      pname   = "async";
      version = "1.5";
      src = fetchFromGitHub {
        owner  = "jwiegley";
        repo   = "emacs-async";
        rev    = "v${version}";
        sha256 = "1yq1aby4n5k3caasynhxhakng01qp4099zjbsm633d351ib3h20g";
      };
      meta = {
        description = "Asynchronous processing in Emacs";
  