anchor.diff:         "\n",
          f("~s~n", [format_decoders(Defs, AnRes, Opts)]),
          "\n",
  -       f("~s~n", [format_msg_merge_code(Defs)]),
  +       f("~s~n", [format_msg_merge_code(Defs, AnRes)]),
          "\n",
          f("verify_msg(Msg) ->~n" %% Option to use gpb:verify_msg??
            "    ~s.~n", [format_verifier_topcase(4, Defs, "Msg")]),
  
positive.code:                     end,
                      sets:new(),
                      Defs).
  
  fold_msg_fields(Fun, InitAcc, Defs) ->
      lists:foldl(fun({{msg, MsgName}, Fields}, Acc) ->
  
negative.code: 
  analyze_defs(Defs) ->
      #anres{used_types      = find_used_types(Defs),
             known_msg_size  = find_msgsizes_known_at_compile_time(Defs),
             msg_occurrences = find_msg_occurrences(Defs)}.
  
  find_used_types(Defs) ->
      fold_msg_fields(fun(_MsgName, #field{type=Type}, Acc) ->
  