anchor.diff:  flatten({nop, Enclosed}) ->
       flatten(Enclosed);
   flatten({comment, Text}) ->
  -    Comment = escape_html_comment(Text, <<>>),
  +    Comment = binary:replace(Text, <<"-->">>, <<"-- >">>, [global]),
       <<"<!--", Comment/binary, "-->">>;
   flatten({sanitized_html, Html}) ->
       Html;
  
positive.code: try_amp(_B, _, _Acc) -> 
      false.
  
  
  is_valid_ent_char(C) ->
      (C >= $a andalso C =< $z) orelse (C >= $A andalso C =< $Z).
  
negative.code: 
  ensure_escaped_amp(<<>>, Acc) ->
      Acc;
  ensure_escaped_amp(<<"<!--", Rest/binary>>, Acc) ->
      case try_comment(Rest, <<Acc/binary, "<!--">>) of
          false -> Acc;
          {Rest1, Acc1} -> ensure_escaped_amp(Rest1, Acc1)
      end;
  ensure_escaped_amp(<<$&, Rest/binary>>, Acc) ->
      case try_amp(Rest, in_amp, <<>>) of
          {Amp,Rest1} -> ensure_escaped_amp(Rest1, <<Acc/binary, $&, Amp/binary>>);
  