anchor.diff:          {ok, UuidsWithTreeIds} ->
               case lists:any(fun({FileUuid, _}) -> FileUuid =:= ExpectedFileUuid end, UuidsWithTreeIds) of
                   true -> {ok, ExpectedFileUuid};
  -                false -> {error, not_found}
  +                false -> {error, {conflicting_uuids, lists:map(fun({FileUuid, _}) -> FileUuid end, UuidsWithTreeIds)}}
               end;
           {error, not_found} ->
               {error, not_found}
  
positive.code:             end,
  
              case map_to_existing_file_uuid(ParentUuid, FileName, FileBaseName, FileUuid) of
                  {error, not_found} ->
                      % Link from Parent to FileBaseName is missing.
                      % We must check deletion marker to ensure that file may be synced.
                      % Deletion markers are removed if and only if file was successfully deleted from storage.
  
negative.code:             end, UuidsWithTreeIds),
              case Filtered of
                  [{FileUuid, _}] -> {ok, FileUuid};
                  _ -> {error, {conflicting_uuids, lists:map(fun({FileUuid, _}) -> FileUuid end, UuidsWithTreeIds)}}
              end;
          {error, not_found} ->
              {error, not_found}
  