1 files changed, 16 insertions, 0 deletions
diff --git a/test/ruby/test_defined.rb b/test/ruby/test_defined.rb
index 2552626b9e..99c866fc2d 100644
--- a/test/ruby/test_defined.rb
+++ b/test/ruby/test_defined.rb
@@ -136,4 +136,20 @@ class TestDefined < Test::Unit::TestCase
     bug5786 = '[ruby-dev:45021]'
     assert_nil(defined?(raise("[Bug#5786]")::A), bug5786)
   end
+
+  def test_define_method
+    bug6644 = '[ruby-core:45831]'
+    a = Class.new do
+      def self.def_f!;
+        singleton_class.send(:define_method, :f) { defined? super }
+      end
+    end
+    aa = Class.new(a)
+    a.def_f!
+    assert_nil(a.f)
+    assert_nil(aa.f)
+    aa.def_f!
+    assert_equal("super", aa.f, bug6644)
+    assert_nil(a.f, bug6644)
+  end
 end