--- /dev/null	2019-03-11 09:22:42.048915961 +0100
+++ new/test/hotspot/jtreg/runtime/valhalla/valuetypes/FlattenableSemanticTest.java	2019-03-11 14:27:43.754353806 +0100
@@ -0,0 +1,150 @@
+/*
+ * Copyright (c) 2018, Oracle and/or its affiliates. All rights reserved.
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This code is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 only, as
+ * published by the Free Software Foundation.
+ *
+ * This code is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+ * version 2 for more details (a copy is included in the LICENSE file that
+ * accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License version
+ * 2 along with this work; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
+ * or visit www.oracle.com if you need additional information or have any
+ * questions.
+ */
+package runtime.valhalla.valuetypes;
+
+import java.lang.invoke.*;
+
+import jdk.experimental.value.MethodHandleBuilder;
+
+import jdk.test.lib.Asserts;
+
+/*
+ * @test
+ * @summary Flattenable field semantic test
+ * @modules java.base/jdk.experimental.bytecode
+ *          java.base/jdk.experimental.value
+ * @library /test/lib
+ * @compile -XDemitQtypes -XDenableValueTypes -XDallowWithFieldOperator Point.java JumboValue.java
+ * @compile -XDemitQtypes -XDenableValueTypes -XDallowWithFieldOperator FlattenableSemanticTest.java
+ * @run main/othervm -Xint -XX:ValueFieldMaxFlatSize=64 -XX:+EnableValhalla runtime.valhalla.valuetypes.FlattenableSemanticTest
+ * @run main/othervm -Xcomp -XX:+EnableValhalla -XX:ValueFieldMaxFlatSize=64 runtime.valhalla.valuetypes.FlattenableSemanticTest
+ * // debug: -XX:+PrintValueLayout -XX:-ShowMessageBoxOnError
+ */
+public class FlattenableSemanticTest {
+
+    static Point.box nfsp;
+    static Point.val fsp;
+
+    Point.box nfip;
+    Point.val fip;
+
+    static JumboValue.box nfsj;
+    static JumboValue.val fsj;
+
+    JumboValue.box nfij;
+    JumboValue.val fij;
+
+    static Object getNull() {
+        return null;
+    }
+
+    FlattenableSemanticTest() { }
+
+    public static void main(String[] args) {
+        FlattenableSemanticTest test = new FlattenableSemanticTest();
+
+        // Uninitialized value fields must be null for non flattenable fields
+        Asserts.assertNull(nfsp, "Invalid non null value for unitialized non flattenable field");
+        Asserts.assertNull(nfsj, "Invalid non null value for unitialized non flattenable field");
+        Asserts.assertNull(test.nfip, "Invalid non null value for unitialized non flattenable field");
+        Asserts.assertNull(test.nfij, "Invalid non null value for unitialized non flattenable field");
+
+        // fsp.equals(null);
+
+        // Uninitialized value fields must be non null for flattenable fields
+        Asserts.assertNotNull(fsp, "Invalid null value for unitialized flattenable field");
+        Asserts.assertNotNull(fsj, "Invalid null value for unitialized flattenable field");
+        Asserts.assertNotNull(test.fip, "Invalid null value for unitialized flattenable field");
+        Asserts.assertNotNull(test.fij, "Invalid null value for unitialized flattenable field");
+
+        // Assigning null must be allowed for non flattenable value fields
+        boolean exception = true;
+        try {
+            nfsp = (Point.box)getNull();
+            nfsp = null;
+            exception = false;
+        } catch (NullPointerException e) {
+            exception = true;
+        }
+        Asserts.assertFalse(exception, "Invalid NPE when assigning null to a non flattenable field");
+
+        try {
+            nfsj = (JumboValue.box)getNull();
+            nfsj = null;
+            exception = false;
+        } catch (NullPointerException e) {
+            exception = true;
+        }
+        Asserts.assertFalse(exception, "Invalid NPE when assigning null to a non flattenable field");
+
+        try {
+            test.nfip = (Point.box)getNull();
+            test.nfip = null;
+            exception = false;
+        } catch (NullPointerException e) {
+            exception = true;
+        }
+        Asserts.assertFalse(exception, "Invalid NPE when assigning null to a non flattenable field");
+
+        try {
+            test.nfij = (JumboValue.box)getNull();
+            test.nfij = null;
+            exception = false;
+        } catch (NullPointerException e) {
+            exception = true;
+        }
+        Asserts.assertFalse(exception, "Invalid NPE when assigning null to a non flattenable field");
+
+        // Assigning null to a flattenable value field must trigger a NPE
+        exception = false;
+        try {
+            fsp = (Point)getNull();
+        } catch(NullPointerException e) {
+            exception = true;
+        }
+        Asserts.assertTrue(exception, "NPE not thrown when assigning null to a flattenable field");
+        exception = false;
+        try {
+            fsj = (JumboValue)getNull();
+        } catch(NullPointerException e) {
+            exception = true;
+        }
+        Asserts.assertTrue(exception, "NPE not thrown when assigning null to a flattenable field");
+        exception = false;
+        try {
+            test.fip = (Point)getNull();
+        } catch(NullPointerException e) {
+            exception = true;
+        }
+        Asserts.assertTrue(exception, "NPE not thrown when assigning null to a flattenable field");
+        exception = false;
+        try {
+            test.fij = (JumboValue)getNull();
+        } catch(NullPointerException e) {
+            exception = true;
+        }
+        Asserts.assertTrue(exception, "NPE not thrown when assigning null to a flattenable field");
+        exception = false;
+    }
+
+}