anchor.diff:                            case Compatible of
                                 true ->
                                     matching_renamings_with_tags(NodesSet, {Map, Tags},
  -                                                               {PastMap, PastTags});
  +                                                               {PastMap, PastTags}, Trivial);
                                 false ->
                                     []
                             end
  
positive.code:                                 [{OldNodeA, NewNodeA}, {OldNodeB, NewNodeB}]) ++
                          rewrite_map(CandidateMap, CandidateTags, CurrentTags,
                                      [{OldNodeA, NewNodeB}, {OldNodeB, NewNodeA}]);
                  _ ->
                      %% just try some random mapping just in case. It
                      %% will work nicely if NewNode-s are all being
                      %% added to cluster (and CurrentNode-s thus
  
negative.code:     TagRenaming ++ build_tag_renaming(Rest).
  
  matching_renamings_same_vbuckets_count(KeepNodesSet, CurrentTags,
                                         CandidateMap, CandidateTags, Trivial) ->
      CandidateNodesSet = map_nodes_set(CandidateMap),
      case sets:size(CandidateNodesSet) =:= sets:size(KeepNodesSet) of
          false ->
              [];
          true ->
              CurrentNotCommon = sets:subtract(KeepNodesSet, CandidateNodesSet),
              case {sets:size(CurrentNotCommon), Trivial} of
                  {0, _} ->
                      case lists:sort(CandidateTags) == lists:sort(CurrentTags) of
                          true ->
                              [CandidateMap];
                          false ->
                              matching_tag_renaming(CandidateMap, CandidateTags,
                                                    CurrentTags, Trivial)
                      end;
                  {1, false} ->
                      [NewNode] = sets:to_list(CurrentNotCommon),
                      [OldNode] = sets:to_list(sets:subtract(CandidateNodesSet, KeepNodesSet)),
  
                      rewrite_map(CandidateMap, CandidateTags, CurrentTags,
                                  [{OldNode, NewNode}]);
                  {2, false} ->
                      [NewNodeA, NewNodeB] = sets:to_list(CurrentNotCommon),
                      [OldNodeA, OldNodeB] = sets:to_list(sets:subtract(CandidateNodesSet, KeepNodesSet)),
  
  