anchor.diff:  
   hide_calls(LC, MaxLine) ->
       LineId0 = MaxLine + 1,
  -    {NLC, _, D} = hide(LC, LineId0, dict:new()),
  +    {NLC, _, D} = hide(LC, LineId0, maps:new()),
       {NLC, D}.
   
   %% v/1 and local calls are hidden.
   hide({value,L,V}, Id, D) ->
       A = erl_anno:new(Id),
  -    {{atom,A,ok}, Id+1, dict:store(Id, {value,L,V}, D)};
  +    {{atom,A,ok}, Id+1, maps:put(Id, {value,L,V}, D)};
   hide({call,L,{atom,_,N}=Atom,Args}, Id0, D0) ->
       {NArgs, Id, D} = hide(Args, Id0, D0),
       C = case erl_internal:bif(N, length(Args)) of
  
positive.code:     L = erl_anno:line(A),
      if
          L > MaxLine ->
              dict:fetch(L, D);
          true ->
              E
      end;
  
negative.code:     Line = erl_anno:line(A),
      if
          Line > MaxLine ->
              {call,Atom} = map_get(Line, D),
              {call,L,Atom,unhide_calls(Args, MaxLine, D)};
          true ->
              {call,A,F,unhide_calls(Args, MaxLine, D)}
  