anchor.diff:  								 ([{identifier, _, 'safeseq'}], {{AstAcc, InfoAcc}, TreeWalkerAcc}) ->
   								    {{AstAcc, InfoAcc}, TreeWalkerAcc#treewalker{safe = true}};
   								 (Filter, {{AstAcc, InfoAcc}, TreeWalkerAcc}) ->
  -								    {Ast, AstInfo} = filter_ast1(Filter, AstAcc, Context),
  -								    {{Ast, merge_info(InfoAcc, AstInfo)}, TreeWalkerAcc}
  +								    {{Ast, AstInfo}, TW} = filter_ast1(Filter, AstAcc, Context, TreeWalkerAcc),
  +								    {{Ast, merge_info(InfoAcc, AstInfo)}, TW}
   							    end, {{erl_syntax:application(
   								     erl_syntax:atom(erlang),
   								     erl_syntax:atom(iolist_to_binary),
  
positive.code:         {'apply_filter', Variable, Filter} ->
              filter_ast(Variable, Filter, Context, TreeWalker);
          {'attribute', _} = Variable ->
              {Ast, VarName} = resolve_variable_ast(Variable, Context, EmptyIfUndefined),
              {{Ast, #ast_info{var_names = [VarName]}}, TreeWalker};
          {'variable', _} = Variable ->
              {Ast, VarName} = resolve_variable_ast(Variable, Context, EmptyIfUndefined),
              {{Ast, #ast_info{var_names = [VarName]}}, TreeWalker};
          {extension, Tag} ->
              extension_ast(Tag, Context, TreeWalker)
      end.
  
negative.code: 						   {{S, _}, _} = string_ast(unescape_string_literal(Str), Context, TreeWalker),
  						   {S, VarNamesAcc};
  						({variable, _}=Var, VarNamesAcc) ->
  						   {{V, #ast_info{ var_names=[VarName] }}, _} = resolve_variable_ast(Var, Context, TreeWalker, true),
  						   {V, [VarName|VarNamesAcc]};
  						({number_literal, _, Num}, VarNamesAcc) ->
  						   {format(erl_syntax:integer(Num), Context, TreeWalker), VarNamesAcc};
  