diff --git a/KNOWNBUGS.rb b/KNOWNBUGS.rb
index b97a08d928..8eea8ec146 100644
--- a/KNOWNBUGS.rb
+++ b/KNOWNBUGS.rb
@@ -3,3 +3,11 @@
 # So all tests will cause failure.
 #
 
+assert_normal_exit %q{
+  r = Range.allocate
+  def r.<=>(o) true end
+  r.instance_eval { initialize r, r }
+  r.inspect
+}
+
+