--- a/src/java.base/share/classes/java/util/concurrent/ConcurrentSkipListMap.java	Fri May 24 15:34:14 2019 +0100
+++ b/src/java.base/share/classes/java/util/concurrent/ConcurrentSkipListMap.java	Fri May 24 08:39:37 2019 -0700
@@ -1712,9 +1712,8 @@
         Map<?,?> m = (Map<?,?>) o;
         try {
             Comparator<? super K> cmp = comparator;
-            @SuppressWarnings("unchecked")
-            Iterator<Map.Entry<?,?>> it =
-                (Iterator<Map.Entry<?,?>>)m.entrySet().iterator();
+            // See JDK-8223553 for Iterator type wildcard rationale
+            Iterator<? extends Map.Entry<?,?>> it = m.entrySet().iterator();
             if (m instanceof SortedMap &&
                 ((SortedMap<?,?>)m).comparator() == cmp) {
                 Node<K,V> b, n;