From da5bd0047d6c961105da210c69d4c88421324b70 Mon Sep 17 00:00:00 2001
From: Nobuyoshi Nakada <nobu@ruby-lang.org>
Date: Thu, 23 Apr 2020 09:43:30 +0900
Subject: [PATCH] Test for [Bug #16669]

---
 test/ruby/test_defined.rb | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/test/ruby/test_defined.rb b/test/ruby/test_defined.rb
index d254857dea..267744ef08 100644
--- a/test/ruby/test_defined.rb
+++ b/test/ruby/test_defined.rb
@@ -61,6 +61,14 @@ class TestDefined < Test::Unit::TestCase
     f.attrasgn_test { |v| assert(v) }
   end
 
+  def test_defined_undef
+    x = Object.new
+    def x.foo; end
+    assert(defined?(x.foo))
+    x.instance_eval {undef :foo}
+    assert(!defined?(x.foo), "undefed method should not be defined?")
+  end
+
   def test_defined_yield
     assert(defined_test)		# not iterator
     assert(!defined_test{})	        # called as iterator