anchor.diff:                     [FieldTxt2, LineUpStr2, FNum,
                       [", " || TypeComment /= ""], TypeComment]);
              ({I, #gpb_oneof{name=Name}=Field}) ->
  -                TypeStr = ?f("~s", [type_to_typestr(Field, Defs, CompileOpts)]),
  -                CommaSep = if I < length(Fields) -> ",";
  -                              true               -> "" %% last entry
  +                LineLead = if MappingAndUnset == {maps, omitted} -> "%% ";
  +                              true -> ""
                              end,
  -                FieldTxt1 = indent(Indent, ?f("~w", [Name])),
  +                TypeStr = ?f("~s", [type_to_typestr(Field, Defs, Opts)]),
  +                CommaSep = if I < LastIndex -> ",";
  +                              true          -> "" %% last entry
  +                           end,
  +                FieldTxt0 = ?f("~s~w", [LineLead, Name]),
  +                FieldTxt1 = indent(Indent, FieldTxt0),
                   FieldTxt2 = if TypeSpecs ->
                                       LineUp = lineup(iolist_size(FieldTxt1), 32),
                                       ?f("~s~s~s ~s~s", [FieldTxt1, LineUp,
  
positive.code:     Default = false,
      proplists:get_value(type_specs, Opts, Default).
  
  type_to_typestr(#?gpb_field{type=Type, occurrence=Occurrence}, Defs, Opts) ->
      case Occurrence of
          required -> type_to_typestr_2(Type, Defs, Opts);
          repeated -> "[" ++ type_to_typestr_2(Type, Defs, Opts) ++ "]";
          optional -> type_to_typestr_2(Type, Defs, Opts) ++ " | 'undefined'"
      end;
  type_to_typestr(#gpb_oneof{fields=OFields}, Defs, Opts) ->
      string:join(
        ["undefined"
         | [?f("{~s, ~s}", [Name, type_to_typestr_2(Type, Defs, Opts)])
            || #?gpb_field{name=Name, type=Type} <- OFields]],
        " | ").
  
  type_to_typestr_2(sint32, _Defs, _Opts)   -> "integer()";
  
negative.code:                ""
         end,
         "\n",
         format_export_types(Defs, Opts),
         "\n",
         [[?f("~s~n", [format_load_nif(Mod, Opts)]),
           "\n"]
  