1 files changed, 14 insertions, 0 deletions
diff --git a/test/ruby/test_weakkeymap.rb b/test/ruby/test_weakkeymap.rb
index 6b3ffbb81f..91c1538076 100644
--- a/test/ruby/test_weakkeymap.rb
+++ b/test/ruby/test_weakkeymap.rb
@@ -61,6 +61,20 @@ class TestWeakKeyMap < Test::Unit::TestCase
     refute @wm[k]
   end
 
+  def test_clear_bug_20691
+    assert_normal_exit(<<~RUBY)
+      map = ObjectSpace::WeakKeyMap.new
+
+      1_000.times do
+        1_000.times do
+          map[Object.new] = nil
+        end
+
+        map.clear
+      end
+    RUBY
+  end
+
   def test_inspect
     x = Object.new
     k = Object.new