ES6: Object.setPrototypeOf(func, null) breaks instanceof

test/mjsunit/harmony/proxies.js

Index: test/mjsunit/harmony/proxies.js
diff --git a/test/mjsunit/harmony/proxies.js b/test/mjsunit/harmony/proxies.js
index 8f24d4d9add72bc838e3ddd6679761d3df7ea9f6..28f07496de5a9a0100f3443fb2fc52bbe64bf836 100644
--- a/test/mjsunit/harmony/proxies.js
+++ b/test/mjsunit/harmony/proxies.js
@@ -1018,7 +1018,19 @@ TestHasOwnThrow({
   var o4 = Object.create(o2)
   var o5 = Object.create(o3)
 
-  function handler(o) { return {get: function() { return o } } }
+  function handler(o) {
+    return {
+      get: function(r, p) {
+        // We want to test prototype lookup, so ensure the proxy
+        // offers OrdinaryHasInstance behavior.
+        if (p === Symbol.hasInstance) {
+          return undefined;
+        }
+        return o;
+      }
+    }
+  }
+
   var f0 = new Proxy(function() {}, handler(o0))
   var f1 = new Proxy(function() {}, handler(o1))
   var f2 = new Proxy(function() {}, handler(o2))