anchor.diff:  %% These are used for the built-in functions of 'erlang'
   %% =====================================================================
   
  +t_adler32() ->
  +  t_non_neg_integer().
  +
  +t_crc32() ->
  +  t_non_neg_integer().
  +
   t_decode_packet_option() ->
     t_sup([t_tuple([t_atom('packet_size'), t_non_neg_integer()]),
   	 t_tuple([t_atom('line_length'), t_non_neg_integer()])]).
  
positive.code: arg_types(erlang, crc32, 1) ->
    [t_iodata()];
  arg_types(erlang, crc32, 2) ->
    [t_integer(), t_iodata()];
  arg_types(erlang, crc32_combine, 3) ->
    [t_integer(), t_integer(), t_integer()];
  arg_types(erlang, date, 0) ->
    [];
  arg_types(erlang, decode_packet, 3) ->
  
negative.code:   [t_integer()];
  arg_types(erlang, abs, 1) ->
    [t_number()];
  arg_types(erlang, adler32, 1) ->
    [t_iodata()];
  arg_types(erlang, adler32, 2) ->
    [t_adler32(), t_iodata()];
  arg_types(erlang, adler32_combine, 3) ->
    [t_adler32(), t_adler32(), t_non_neg_integer()];
  arg_types(erlang, append_element, 2) ->
    [t_tuple(), t_any()];
  arg_types(erlang, apply, 2) ->
  