{"ast_node_type":"variable","tokens":[{"end":85,"kind":"keyword","start":0,"text":"let"}]}
        let res = self.context.new_call(self.location, count_leading_zeroes, &[arg]);
        let count_leading_zeroes = self.context.get_builtin_function(count_leading_zeroes);
        self.context.new_cast(self.location, res, result_type)