anchor.diff:  vars_in_defs(Ds, S) ->
       vars_in_defs(Ds, S, []).
   
  -vars_in_defs([{_, F} | Ds], S, A) ->
  -    vars_in_defs(Ds, S, ordsets:union(variables(F, S), A));
  +vars_in_defs([{_, Post} | Ds], S, A) ->
  +    vars_in_defs(Ds, S, ordsets:union(variables(Post, S), A));
   vars_in_defs([], _, A) ->
       A.
   
  
positive.code: 	    %% Constant literals are not labeled.
  	    {T, N};
  	var ->
  	    case dict:find(var_name(T), Env) of
  		{ok, L} ->
  		    {As, _} = label_ann(T, L),
  		    N1 = N;
  		error ->
  		    {As, N1} = label_ann(T, N)
  	    end,
  	    {set_ann(T, As), N1};
  	values ->
  	    {Ts, N1} = label_list(values_es(T), N, Env),
  
negative.code: -module(cerl_trees).
  
  -export([depth/1, fold/3, free_variables/1, get_label/1, label/1, label/2, 
  	 map/2, mapfold/3, mapfold/4, size/1, variables/1]).
  
  -import(cerl, [alias_pat/1, alias_var/1, ann_c_alias/3, ann_c_apply/3,
  	       ann_c_binary/2, ann_c_bitstr/6, ann_c_call/4,
  