diff -r 88502b1cf76f -r 7799a51dbe30 src/java.base/share/classes/jdk/internal/PreviewFeature.java
--- a/src/java.base/share/classes/jdk/internal/PreviewFeature.java	Mon Sep 09 11:43:16 2019 -0400
+++ b/src/java.base/share/classes/jdk/internal/PreviewFeature.java	Wed Nov 27 09:00:01 2019 +0100
@@ -54,6 +54,8 @@
     public boolean essentialAPI() default false;
 
     public enum Feature {
-        TEXT_BLOCKS;
+        PATTERN_MATCHING_IN_INSTANCEOF,
+        TEXT_BLOCKS,
+        ;
     }
 }