==================
Arrow body keeps trailing chain inside the body
==================

void main() {
  fn((_) => Random().nextInt(256));
}

---

(program
  (function_signature
    (void_type)
    (identifier)
    (formal_parameter_list))
  (function_body
    (block
      (expression_statement
        (method_invocation
          (identifier)
          (argument_part
            (arguments
              (argument
                (function_expression
                  (formal_parameter_list
                    (formal_parameter
                      (identifier)))
                  (function_expression_body
                    (identifier)
                    (selector
                      (argument_part
                        (arguments)))
                    (selector
                      (unconditional_assignable_selector
                        (identifier)))
                    (selector
                      (argument_part
                        (arguments
                          (argument
                            (decimal_integer_literal)))))))))))))))
