anchor.diff:  %%  switch list to a #b_br{}.
   
   -spec normalize(b_set() | terminator()) ->
  -                       b_set() | terminator().
  +          b_set() | terminator().
   
   normalize(#b_set{op={bif,Bif},args=Args}=Set) ->
       case {is_commutative(Bif),Args} of
  
positive.code: get_anno(Key, Construct) ->
      map_get(Key, get_anno(Construct)).
  
  -spec get_anno(atom(), construct(),any()) -> any().
  
  get_anno(Key, Construct, Default) ->
      maps:get(Key, get_anno(Construct), Default).
  
negative.code: 
  -import(lists, [foldl/3,mapfoldl/3,member/2,reverse/1,sort/1]).
  
  -spec add_anno(Key, Value, Construct0) -> Construct when
        Key :: atom(),
        Value :: any(),
        Construct0 :: construct(),
        Construct :: construct().
  
  add_anno(Key, Val, #b_function{anno=Anno}=Bl) ->
  