anchor.diff:  
   analyze_defs(Defs) ->
       #anres{used_types      = find_used_types(Defs),
  -           known_msg_size  = find_msgsizes_known_at_compile_time(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) ->
  
positive.code:        "\n",
         f("~s~n", [format_decoders(Defs, AnRes, Opts)]),
         "\n",
         f("~s~n", [format_msg_merge_code(Defs)]),
         "\n",
         f("verify_msg(Msg) ->~n" %% Option to use gpb:verify_msg??
           "    ~s.~n", [format_verifier_topcase(4, Defs, "Msg")]),
  
negative.code:     end.
  
  
  format_msg_merge_code(Defs, AnRes) ->
      MsgNames = [MsgName || {{msg, MsgName}, _MsgDef} <- Defs],
      [format_merge_msgs_top_level(MsgNames),
       [format_msg_merger(MsgName, MsgDef, AnRes)
        || {{msg, MsgName}, MsgDef} <- Defs]].
  
  format_merge_msgs_top_level([]) ->
  