1 files changed, 81 insertions, 0 deletions
diff --git a/js/src/jit-test/tests/arguments/mapped-define.js b/js/src/jit-test/tests/arguments/mapped-define.js
new file mode 100644
index 0000000000..0c806f618b
--- /dev/null
+++ b/js/src/jit-test/tests/arguments/mapped-define.js
@@ -0,0 +1,81 @@
+load(libdir + "asserts.js");
+
+function testMapped(a) {
+    assertEq(arguments[0], 1);
+
+    Object.defineProperty(arguments, 0, {value: 23, writable: true, configurable: true});
+    assertEq(arguments[0], 23);
+    assertEq(a, 23);
+
+    a = 12;
+    assertEq(a, 12);
+    assertEq(arguments[0], 12);
+
+    Object.defineProperty(arguments, 0, {value: 9, writable: false, configurable: false});
+    assertEq(arguments[0], 9);
+    assertEq(a, 9);
+
+    a = 4;
+    assertEq(arguments[0], 9);
+    assertEq(a, 4);
+}
+for (var i = 0; i < 5; i++) {
+    testMapped(1);
+}
+
+function testAttributes(x) {
+    Object.defineProperty(arguments, 0, {enumerable:true,
+                                         writable:true,
+                                         configurable:true,
+                                         value: 4});
+
+    // Should inherit enumerable/configurable attributes.
+    Object.defineProperty(arguments, 0, {writable:true,
+                                         value: 8});
+    assertEq(JSON.stringify(Object.getOwnPropertyDescriptor(arguments, 0)),
+             '{"value":8,"writable":true,"enumerable":true,"configurable":true}');
+    assertEq(x, 8);
+
+    // Property becomes non-configurable.
+    Object.defineProperty(arguments, 0, {writable:true,
+                                         configurable:false,
+                                         value: 6});
+    assertEq(JSON.stringify(Object.getOwnPropertyDescriptor(arguments, 0)),
+             '{"value":6,"writable":true,"enumerable":true,"configurable":false}');
+    assertEq(x, 6);
+
+    // Can no longer make it non-enumerable.
+    assertThrowsInstanceOf(() => Object.defineProperty(arguments, 0, {writable:true,
+                                                                      configurable:false,
+                                                                      enumerable:false,
+                                                                      value: 6}),
+                           TypeError);
+
+    // Can no longer make it configurable.
+    assertThrowsInstanceOf(() => Object.defineProperty(arguments, 0, {writable:true,
+                                                                      configurable:true,
+                                                                      value: 6}),
+                           TypeError);
+
+    // Can still make it non-writable.
+    Object.defineProperty(arguments, 0, {writable:false,
+                                         enumerable:true,
+                                         configurable:false,
+                                         value: 3});
+    assertEq(x, 3);
+
+    // No longer a mapped property.
+    x = 5;
+    assertEq(arguments[0], 3);
+
+    // Can no longer make it writable.
+    assertThrowsInstanceOf(() => Object.defineProperty(arguments, 0, {writable:true,
+                                                                      enumerable:true,
+                                                                      configurable:false,
+                                                                      value: 5}),
+                           TypeError);
+    assertEq(x, 5);
+}
+for (var i = 0; i < 5; i++) {
+    testAttributes(i);
+}