1 files changed, 14 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/basic/bug1172503-2.js b/js/src/jit-test/tests/basic/bug1172503-2.js
new file mode 100644
index 000000000..2c65b7161
--- /dev/null
+++ b/js/src/jit-test/tests/basic/bug1172503-2.js
@@ -0,0 +1,14 @@
+load(libdir + "immutable-prototype.js");
+
+var n = 0;
+if (globalPrototypeChainIsMutable()) {
+  this.__proto__ = new Proxy({}, {
+      has: function () {
+          if (++n === 2)
+              return false;
+          a = 0;
+      }
+  });
+  }
+a = 0;
+assertEq(a, 0);