anchor.diff:  msg_defs(Mod, Defs, Opts) ->
       proto_defs(Mod, Defs, Opts).
   
  -do_proto_defs(Defs, Mod, AnRes, Opts) ->
  +do_proto_defs_aux2(Defs, Mod, AnRes, Opts) ->
       case get_output_format(Opts) of
           proto_defs ->
               {ok, Defs};
  
positive.code:     do_file_or_string({Mod, Str}, Opts).
  
  do_file_or_string(In, Opts0) ->
      Opts1 = normalize_alias_opts(Opts0),
      Opts2 = normalize_return_report_opts(Opts1),
      case parse_file_or_string(In, Opts2) of
          {ok, Defs} ->
              Mod = find_out_mod(In, Opts2),
              DefaultOutDir = find_default_out_dir(In),
              Opts3 = Opts2 ++ [{o,DefaultOutDir}],
              proto_defs(Mod, Defs, Opts3);
          {error, Reason} = Error ->
              possibly_report_error(Error, Opts2),
              case proplists:get_bool(return_warnings, Opts2) of
                  true  -> {error, Reason, []};
                  false -> Error
              end
      end.
  
  normalize_alias_opts(Opts) ->
      lists:foldl(fun(F, OptsAcc) -> F(OptsAcc) end,
  
negative.code: %% @doc
  %% Compile a list of pre-parsed definitions to file or to a binary.
  %% See {@link file/2} for information on options and return values.
  proto_defs(Mod, Defs, Opts) ->
      do_proto_defs_aux1(Mod, Defs, normalize_opts(Opts)).
  
  do_proto_defs_aux1(Mod, Defs0, Opts0) ->
      {IsAcyclic, Defs} = try_topsort_defs(Defs0),
      possibly_probe_defs(Defs, Opts0),
      {Warns, Opts1} = possibly_adjust_typespec_opt(IsAcyclic, Opts0),
      AnRes = analyze_defs(Defs, Opts1),
      case verify_opts(Defs, Opts1) of
          ok ->
              Res1 = do_proto_defs_aux2(Defs, clean_module_name(Mod), AnRes,
                                        Opts1),
              return_or_report_warnings_or_errors(Res1, Warns, Opts1,
                                                  get_output_format(Opts1));
          {error, OptError} ->
              return_or_report_warnings_or_errors({error, OptError}, [], Opts1,
                                                  get_output_format(Opts1))
      end.
  
  verify_opts(Defs, Opts) ->
  