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

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

---

(program
  (function_declaration
    (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
                      (method_invocation
                        (unconditional_assignable_selector
                          (method_invocation
                            (identifier)
                            (argument_part
                              (arguments)))
                          (assignable_operator)
                          (identifier))
                        (argument_part
                          (arguments
                            (argument
                              (decimal_integer_literal))))))))))))))))
