1 files changed, 55 insertions, 0 deletions
diff --git a/js/src/tests/non262/extensions/proxy-array-target-length-definition.js b/js/src/tests/non262/extensions/proxy-array-target-length-definition.js
new file mode 100644
index 0000000000..c573c4ba08
--- /dev/null
+++ b/js/src/tests/non262/extensions/proxy-array-target-length-definition.js
@@ -0,0 +1,55 @@
+/*
+ * Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/licenses/publicdomain/
+ */
+
+var gTestfile = 'proxy-array-target-length-definition.js';
+var BUGNUMBER = 905947;
+var summary =
+  "Redefining an array's |length| property when redefining the |length| " +
+  "property on a proxy with an array as target";
+
+print(BUGNUMBER + ": " + summary);
+
+/**************
+ * BEGIN TEST *
+ **************/
+
+var arr = [];
+var p = new Proxy(arr, {});
+
+function assertThrowsTypeError(f)
+{
+    try {
+        f();
+        assertEq(false, true, "Must have thrown");
+    } catch (e) {
+        assertEq(e instanceof TypeError, true, "Must have thrown TypeError");
+    }
+}
+
+// Redefining non-configurable length should throw a TypeError
+assertThrowsTypeError(function () { Object.defineProperty(p, "length", { value: 17, configurable: true }); });
+
+// Same here.
+assertThrowsTypeError(function () { Object.defineProperty(p, "length", { value: 42, enumerable: true }); });
+
+// Check the property went unchanged.
+var pd = Object.getOwnPropertyDescriptor(p, "length");
+assertEq(pd.value, 0);
+assertEq(pd.writable, true);
+assertEq(pd.enumerable, false);
+assertEq(pd.configurable, false);
+
+var ad = Object.getOwnPropertyDescriptor(arr, "length");
+assertEq(ad.value, 0);
+assertEq(ad.writable, true);
+assertEq(ad.enumerable, false);
+assertEq(ad.configurable, false);
+
+/******************************************************************************/
+
+if (typeof reportCompare === "function")
+  reportCompare(true, true);
+
+print("Tests complete");