1 files changed, 33 insertions, 0 deletions
diff --git a/js/src/tests/ecma_6/Function/arguments-extra-property.js b/js/src/tests/ecma_6/Function/arguments-extra-property.js
new file mode 100644
index 000000000..017734382
--- /dev/null
+++ b/js/src/tests/ecma_6/Function/arguments-extra-property.js
@@ -0,0 +1,33 @@
+var BUGNUMBER = 1263811;
+var summary = "GetElem for modified arguments shouldn't be optimized to get original argument.";
+
+print(BUGNUMBER + ": " + summary);
+
+function testModifyFirst() {
+    function f() {
+        Object.defineProperty(arguments, 1, { value: 30 });
+        assertEq(arguments[1], 30);
+    }
+    for (let i = 0; i < 10; i++)
+        f(10, 20);
+}
+testModifyFirst();
+
+function testModifyLater() {
+    function f() {
+        var ans = 20;
+        for (let i = 0; i < 10; i++) {
+            if (i == 5) {
+                Object.defineProperty(arguments, 1, { value: 30 });
+                ans = 30;
+            }
+            assertEq(arguments[1], ans);
+        }
+    }
+    for (let i = 0; i < 10; i++)
+        f(10, 20);
+}
+testModifyLater();
+
+if (typeof reportCompare === "function")
+    reportCompare(true, true);