From: "shugo (Shugo Maeda)" Date: 2013-09-29T22:07:24+09:00 Subject: [ruby-dev:47735] [ruby-trunk - Bug #8965][Closed] SEGV when a refined method is undefined by undef Issue #8965 has been updated by shugo (Shugo Maeda). Status changed from Assigned to Closed I reported this issue to ruby-dev by accident, so refiled as #8966. ---------------------------------------- Bug #8965: SEGV when a refined method is undefined by undef https://bugs.ruby-lang.org/issues/8965#change-42081 Author: shugo (Shugo Maeda) Status: Closed Priority: Normal Assignee: shugo (Shugo Maeda) Category: core Target version: current: 2.1.0 ruby -v: ruby 2.1.0dev (2013-09-27 trunk 43073) [i686-linux] Backport: 1.9.3: UNKNOWN, 2.0.0: UNKNOWN The following code causes SEGV: module Foo refine Object do def foo puts "foo" end end end using Foo class Object undef foo end foo I guess undef is not aware of refinements. -- http://bugs.ruby-lang.org/