anchor.diff:  
   new_default_msg(MsgName, MsgDefs) ->
       MsgDef = keyfetch(MsgName, MsgDefs),
  -    {MsgName, lists:map(fun(#field{name=FName, multiplicity=repeated}) ->
  +    {MsgName, lists:map(fun(#field{name=FName, occurrence=repeated}) ->
                                   {FName, []};
                              (#field{name=FName, type={msg,FieldMsgName}}) ->
                                   {FName, new_default_msg(FieldMsgName, MsgDefs)};
  
positive.code:     MsgDef = keyfetch(MsgName, MsgDefs),
      {MsgName,
       lists:foldl(
         fun(#field{name=FName, multiplicity=repeated}, AccFields) ->
                 PrevSeq = keyfetch(FName, AccFields),
                 NewSeq = keyfetch(FName, NewFields),
                 replace_field(FName, append_seqs(PrevSeq, NewSeq), AccFields);
  
negative.code: -include_lib("eunit/include/eunit.hrl").
  
  -record(field,
          {name, fnum, type, occurrence, opts}).
  
  decode_msg(MsgName, MsgDefs, Bin) ->
      Msg    = new_default_msg(MsgName, MsgDefs),
  