--- a/nashorn/src/jdk/nashorn/internal/codegen/MethodEmitter.java	Fri Oct 11 06:50:06 2013 +0200
+++ b/nashorn/src/jdk/nashorn/internal/codegen/MethodEmitter.java	Fri Oct 11 10:56:08 2013 +0200
@@ -1793,7 +1793,7 @@
         debug("dynamic_set", name, peekType());
 
         Type type = peekType();
-        if (type.isObject()) { //promote strings to objects etc
+        if (type.isObject() || type.isBoolean()) { //promote strings to objects etc
             type = Type.OBJECT;
             convert(Type.OBJECT); //TODO bad- until we specialize boolean setters,
         }

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/nashorn/test/script/basic/JDK-8026292.js	Fri Oct 11 10:56:08 2013 +0200
@@ -0,0 +1,65 @@
+/*
+ * Copyright (c) 2010, 2013, 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-8026292: Megamorphic setter fails with boolean value
+ *
+ * @test
+ * @run
+ */
+
+function megamorphic(o) {
+    o.w = true;
+    if (!o.w)
+        throw new Error();
+}
+
+// Calls below must exceed megamorphic callsite threshhold
+for (var i = 0; i < 10; i++) {
+    megamorphic({a: 1});
+    megamorphic({b: 1});
+    megamorphic({c: 1});
+    megamorphic({d: 1});
+    megamorphic({e: 1});
+    megamorphic({f: 1});
+    megamorphic({g: 1});
+    megamorphic({h: 1});
+    megamorphic({i: 1});
+    megamorphic({j: 1});
+    megamorphic({k: 1});
+    megamorphic({l: 1});
+    megamorphic({m: 1});
+    megamorphic({n: 1});
+    megamorphic({o: 1});
+    megamorphic({p: 1});
+    megamorphic({q: 1});
+    megamorphic({r: 1});
+    megamorphic({s: 1});
+    megamorphic({t: 1});
+    megamorphic({u: 1});
+    megamorphic({v: 1});
+    megamorphic({w: 1});
+    megamorphic({x: 1});
+    megamorphic({y: 1});
+    megamorphic({z: 1});
+}