anchor.diff:  
     mkCoqPackages_8_6 = self: let callPackage = newScope self; in rec {
       inherit callPackage;
  -    coq = coq_8_6;
  +    coq = callPackage ../applications/science/logic/coq {};
       coqPackages = coqPackages_8_6;
   
       coq-ext-lib = callPackage ../development/coq-modules/coq-ext-lib {};
  
positive.code:   coqPackages_8_5 = mkCoqPackages_8_5 coqPackages_8_5;
    coqPackages_8_6 = mkCoqPackages_8_6 coqPackages_8_6;
    coqPackages = coqPackages_8_6;
  
    cryptoverif = callPackage ../applications/science/logic/cryptoverif { };
  
  
negative.code:     camlp5 = ocamlPackages_3_12_1.camlp5_transitional;
      lablgtk = ocamlPackages_3_12_1.lablgtk_2_14;
    };
  
    mkCoqPackages_8_4 = self: let callPackage = newScope self; in {
      inherit callPackage;
      coq = callPackage ../applications/science/logic/coq/8.4.nix {
        inherit (ocamlPackages_4_02) ocaml findlib lablgtk;
        camlp5 = ocamlPackages_4_02.camlp5_transitional;
      };
      coqPackages = coqPackages_8_4;
  
      contribs =
  