anchor.diff:          options         = undefined,
           oneof_decl      = oneof_decl(AllOneofs)
          }
  -     || {{msg,MsgName}, Fields} <- Defs].
  -
  -field_defs_to_mgstype_fields(Fields, AllOneofs) ->
  -    lists:append([field_def_to_msgtype_field(Field, AllOneofs)
  +     || {{msg,MsgName}, Fields} <- Defs] ++
  +        [#'DescriptorProto'{
  +            name            = atom_to_ustring(MsgName),
  +            field           = field_defs_to_mgstype_fields(
  +                                Fields, AllOneofs, MapTypesToPseudoMsgNames),
  +            extension       = [],
  +            nested_type     = [],
  +            enum_type       = [],
  +            extension_range = [],
  +            options         = #'MessageOptions'{map_entry=true},
  +            oneof_decl      = []
  +           }
  +         || {{msg,MsgName}, Fields} <- MapPseudoMsgs].
  +
  +field_defs_to_mgstype_fields(Fields, AllOneofs, MapTypesToPseudoMsgNames) ->
  +    lists:append([field_def_to_msgtype_field(Field, AllOneofs,
  +                                             MapTypesToPseudoMsgNames)
                     || Field <- Fields]).
   
   field_def_to_msgtype_field(#?gpb_field{name=FName,
  
positive.code: oneof_decl(AllOneofs) ->
      [#'OneofDescriptorProto'{name=atom_to_ustring(Name)} || Name <- AllOneofs].
  
  atom_to_ustring(A) ->
      Utf8Str = atom_to_list(A),
      unicode:characters_to_list(list_to_binary(Utf8Str), utf8).
  
negative.code:     #'FileDescriptorSet'{file = [defs_to_descr_2(Name, Defs)]}.
  
  defs_to_descr_2(Name, Defs) ->
      {TypesToPseudoMsgNames, PseudoMsgs} = compute_map_field_pseudo_msgs(Defs),
      #'FileDescriptorProto'{
         name             = Name,      %% string() | undefined
         package          = defs_to_package(Defs),
         dependency       = [],        %% [string()]
         message_type     = defs_to_msgtype(Defs,
                                            TypesToPseudoMsgNames, PseudoMsgs),
         enum_type        = defs_to_enumtype(Defs),
         service          = defs_to_service(Defs),
         extension        = [],        %% [#'FieldDescriptorProto'{}]
  