--- a/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/JSType.java	Wed Jul 05 22:05:29 2017 +0200
+++ b/nashorn/src/jdk.scripting.nashorn/share/classes/jdk/nashorn/internal/runtime/JSType.java	Tue Aug 16 15:04:51 2016 +0200
@@ -474,6 +474,8 @@
             return toPrimitive((ScriptObject)obj, hint);
         } else if (isPrimitive(obj)) {
             return obj;
+        } else if (hint == Number.class && obj instanceof Number) {
+            return ((Number) obj).doubleValue();
         } else if (obj instanceof JSObject) {
             return toPrimitive((JSObject)obj, hint);
         } else if (obj instanceof StaticClass) {

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/nashorn/test/script/basic/JDK-8163945.js	Tue Aug 16 15:04:51 2016 +0200
@@ -0,0 +1,48 @@
+/*
+ * Copyright (c) 2016, 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.
+ */
+
+/**
+ * JDK-8163945: Honor Number type hint in toPrimitive on Numbers
+ *
+ * @test
+ * @run
+ */
+
+function assertLessThan(a, b) {
+    Assert.assertTrue(a < b);
+    Assert.assertTrue(a <= b);
+    Assert.assertFalse(a >= b);
+    Assert.assertFalse(a > b);
+}
+
+assertLessThan(new java.lang.Long(2), new java.lang.Long(10));
+assertLessThan(new java.lang.Long(2), 10);
+assertLessThan(2, new java.lang.Long(10));
+
+assertLessThan(new java.math.BigInteger(2), new java.math.BigInteger(10));
+assertLessThan(new java.math.BigInteger(2), 10);
+assertLessThan(2, new java.math.BigInteger(10));
+
+assertLessThan(new java.util.concurrent.atomic.AtomicInteger(2), new java.util.concurrent.atomic.AtomicInteger(10));
+assertLessThan(new java.util.concurrent.atomic.AtomicInteger(2), 10);
+assertLessThan(2, new java.util.concurrent.atomic.AtomicInteger(10));