1 files changed, 21 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/basic/bug942390.js b/js/src/jit-test/tests/basic/bug942390.js
new file mode 100644
index 0000000000..9b661a4f44
--- /dev/null
+++ b/js/src/jit-test/tests/basic/bug942390.js
@@ -0,0 +1,21 @@
+load(libdir + "immutable-prototype.js");
+
+var count = 0;
+if (globalPrototypeChainIsMutable()) {
+    Object.defineProperty(__proto__, "__iterator__", {
+        get: (function() {
+            count++;
+        })
+    });
+} else {
+    count = 7;
+}
+
+if (globalPrototypeChainIsMutable())
+    __proto__ = (function(){});
+
+for (var m = 0; m < 7; ++m) {
+    for (var a in 6) {}
+}
+
+assertEq(count, 7);