Issue #9621 has been reported by Tomoyuki Chikanaga.

----------------------------------------
Backport #9621: backport r45308 (Check fptr before trying to dump FILE object fd)
https://bugs.ruby-lang.org/issues/9621

* Author: Tomoyuki Chikanaga
* Status: Assigned
* Priority: Normal
* Assignee: Yui NARUSE
----------------------------------------
r45308

See also https://github.com/ruby/ruby/pull/562




-- 
http://bugs.ruby-lang.org/