1 files changed, 12 insertions, 0 deletions
diff --git a/test/ruby/test_marshal.rb b/test/ruby/test_marshal.rb
index ef987cc7fa..1dc9850d25 100644
--- a/test/ruby/test_marshal.rb
+++ b/test/ruby/test_marshal.rb
@@ -671,4 +671,16 @@ class TestMarshal < Test::Unit::TestCase
       end
     RUBY
   end
+
+  class Bug12974
+    def marshal_dump
+      dup
+    end
+  end
+
+  def test_marshal_dump_recursion
+    assert_raise_with_message(RuntimeError, /same class instance/) do
+      Marshal.dump(Bug12974.new)
+    end
+  end
 end