1 files changed, 14 insertions, 0 deletions
diff --git a/test/ruby/test_module.rb b/test/ruby/test_module.rb
index dbbeca850d..b86efd7005 100644
--- a/test/ruby/test_module.rb
+++ b/test/ruby/test_module.rb
@@ -1280,6 +1280,20 @@ class TestModule < Test::Unit::TestCase
         undef foo
       end
     end
+
+    stderr = EnvUtil.verbose_warning do
+      Module.new do
+        def foo; end
+        mod = self
+        c = Class.new do
+          include mod
+        end
+        c.new.foo
+        def foo; end
+      end
+    end
+    assert_match(/: warning: method redefined; discarding old foo/, stderr)
+    assert_match(/: warning: previous definition of foo/, stderr)
   end
 
   def test_protected_singleton_method