diff -r e036ee8bae56 -r 55d2e10ea134 src/jdk.compiler/share/classes/com/sun/tools/javac/code/Types.java
--- a/src/jdk.compiler/share/classes/com/sun/tools/javac/code/Types.java	Wed Oct 09 10:17:50 2019 -0700
+++ b/src/jdk.compiler/share/classes/com/sun/tools/javac/code/Types.java	Wed Oct 09 10:02:54 2019 -0700
@@ -3745,12 +3745,9 @@
             return cl1;
         } else if (shouldSkip.test(cl1.head, cl2.head)) {
             return union(cl1.tail, cl2.tail, shouldSkip).prepend(cl1.head);
-        } else if (cl1.head.tsym.precedes(cl2.head.tsym, this)) {
-            return union(cl1.tail, cl2, shouldSkip).prepend(cl1.head);
         } else if (cl2.head.tsym.precedes(cl1.head.tsym, this)) {
             return union(cl1, cl2.tail, shouldSkip).prepend(cl2.head);
         } else {
-            // unrelated types
             return union(cl1.tail, cl2, shouldSkip).prepend(cl1.head);
         }
     }