* class.c (rb_define_{class,module}_id_under): register to be

marked, which probably are defined and used internally.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@29518 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/ruby/test_class.rb

@@ -236,4 +236,8 @@ class TestClass < Test::Unit::TestCase
     copy.send(:include, mod)
     assert_equal("mod#foo", copy.new.foo)
   end
+
+  def test_nested_class_removal
+    assert_normal_exit('File.__send__(:remove_const, :Stat); at_exit{File.stat(".")}; GC.start')
+  end
 end