anchor.diff:  build_list([T | Ts], Min, Max, Ack) ->
       Node = build_tree(T),
       Min1 = minpos(node_min(Node), Min),
  -    Max1 = max(node_max(Node), Max),
  +    Max1 = lists:max([node_max(Node), Max]),
       build_list(Ts, Min1, Max1, [Node | Ack]);
   build_list([], Min, Max, Ack) ->
       list_node(Min, Max, lists:reverse(Ack)).
  
positive.code: 	{_, L, _} when is_integer(L) ->
  	    L;
  	Pos ->
  	    refac_io:format("Node:\n~p\n", [Node]),
  	    exit({bad_position, Pos})
      end.
  
  
negative.code: 	    
  	    %% Include L, while preserving Min =< Max.
  	    tree_node(minpos(L, Min),
  		      lists:max([L, Max]),
  		      refac_syntax:type(Node),
  		      refac_syntax:get_attrs(Node),
  		      Subtrees)
  