diff -r 000000000000 -r 6474c204b198 js/src/jit-test/tests/basic/bug763440.js
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/js/src/jit-test/tests/basic/bug763440.js	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,22 @@
+var summary = '';
+var actual = '';
+gcPreserveCode()
+function TestCase(n, d, e, a) {
+  this.name=n;
+}
+function reportCompare (expected, actual, description) {
+  new TestCase
+}
+reportCompare(true, eval++, "Function.prototype.isGenerator present");
+var p = Proxy.create({
+    has : function(id) {}
+});
+Object.prototype.__proto__ = p;
+new TestCase;
+var expect = '';
+reportCompare(expect, actual, summary);
+gczeal(4);
+try {
+  evalcx(".");
+} catch (e) {}
+reportCompare(expect, actual, summary);