anchor.diff:          {'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};
  +            resolve_variable_ast(Variable, Context, TreeWalker, EmptyIfUndefined);
           {'variable', _} = Variable ->
  -            {Ast, VarName} = resolve_variable_ast(Variable, Context, EmptyIfUndefined),
  -            {{Ast, #ast_info{var_names = [VarName]}}, TreeWalker};
  +            resolve_variable_ast(Variable, Context, TreeWalker, EmptyIfUndefined);
           {extension, Tag} ->
               extension_ast(Tag, Context, TreeWalker)
       end.
  
positive.code:     call_ast(Module, erl_syntax:variable("_Variables"), #ast_info{}, TreeWalkerAcc).
  
  call_with_ast(Module, Variable, Context, TreeWalker) ->
      {VarAst, VarName} = resolve_variable_ast(Variable, Context, false),
      call_ast(Module, VarAst, #ast_info{var_names=[VarName]}, TreeWalker).
  
  call_ast(Module, Variable, AstInfo, TreeWalker) ->
      AppAst = erl_syntax:application(
  
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};
  