anchor.diff:         Idx, AM0) ->
       case Bin of
           <<Data:DataLen/binary, _:Pad/binary, T/binary>> ->
  -            {NameT, AvpName, Arity, {I, AM}}
  +            {NameT, Field, Arity, {I, AM}}
                   = incr(Name, Code, Vid, M, Mod, Strict, Opts0, AM0),
   
               Opts = setopts(NameT, Name, M, Opts0),
  
positive.code:     [[As | Avps], [{RC, Avp} | Failed] | Rec];
  
  %% Grouped AVP ...
  acc1([Avps | Acc], [Avp|_] = As, I, Name, AvpName, Arity, Strict, Mod, Opts) ->
      [[As|Avps] | acc2(Acc, Avp, I, Name, AvpName, Arity, Strict, Mod, Opts)];
  
  %% ... or not.
  acc1([Avps | Acc], Avp, I, Name, AvpName, Arity, Strict, Mod, Opts) ->
      [[Avp|Avps] | acc2(Acc, Avp, I, Name, AvpName, Arity, Strict, Mod, Opts)].
  
  %% acc2/9
  
  
negative.code:     [[{rc(Avp), Avp} | Failed] | Rec];
  
  %% Relaxed arities.
  acc2(Acc, Avp, _, _, Field, Arity, Strict, Mod, _)
    when Strict /= decode ->
      pack(Arity, Field, Avp, Mod, Acc);
  
  %% No maximum arity.
  acc2(Acc, Avp, _, _, Field, {_,'*'} = Arity, _, Mod, _) ->
      pack(Arity, Field, Avp, Mod, Acc);
  
  %% Or check.
  acc2(Acc, Avp, I, _, Field, Arity, _, Mod, _) ->
      Mx = max_arity(Arity),
      if Mx =< I ->
              [Failed | Rec] = Acc,
              [[{5009, Avp} | Failed] | Rec];
         true ->
              pack(Arity, Field, Avp, Mod, Acc)
      end.
  
  %% 3588/6733:
  