[es6] Partially implement Reflect.defineProperty.

test/mjsunit/harmony/reflect-define-property.js

-// Copyright 2012 the V8 project authors. All rights reserved.
+// Copyright 2012-2015 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
 //       with the distribution.
 //     * Neither the name of Google Inc. nor the names of its
 //       contributors may be used to endorse or promote products derived
 //       from this software without specific prior written permission.
 //
 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
-// Tests the object.defineProperty method - ES 15.2.3.6
+// Tests the Reflect.defineProperty method - ES6 26.1.3
+// This is adapted from mjsunit/object-define-property.js.
 
-// Flags: --allow-natives-syntax
+// Flags: --allow-natives-syntax --harmony-reflect
+
 
 // Check that an exception is thrown when null is passed as object.
 var exception = false;
 try {
-  Object.defineProperty(null, null, null);
+  Reflect.defineProperty(null, null, null);
 } catch (e) {
   exception = true;
   assertTrue(/called on non-object/.test(e));
 }
 assertTrue(exception);
 
 // Check that an exception is thrown when undefined is passed as object.
 exception = false;
 try {
-  Object.defineProperty(undefined, undefined, undefined);
+  Reflect.defineProperty(undefined, undefined, undefined);
 } catch (e) {
   exception = true;
   assertTrue(/called on non-object/.test(e));
 }
 assertTrue(exception);
 
 // Check that an exception is thrown when non-object is passed as object.
 exception = false;
 try {
-  Object.defineProperty(0, "foo", undefined);
+  Reflect.defineProperty(0, "foo", undefined);
 } catch (e) {
   exception = true;
   assertTrue(/called on non-object/.test(e));
 }
 assertTrue(exception);
 
 // Object.
 var obj1 = {};
 
 // Values.
@@ skipping 39 matching lines @@
 var accessorDefault = {set: function(){} };
 
 var dataConfigurable = { value: 1000, configurable: true };
 
 var dataNoConfigurable = { value: 2000, configurable: false };
 
 var dataWritable = { value: 3000, writable: true};
 
 
 // Check that we can't add property with undefined attributes.
-try {
-  Object.defineProperty(obj1, "foo", undefined);
-  assertTrue(false);
-} catch (e) {
-  assertTrue(/must be an object/.test(e));
-}
+assertThrows(function() { Reflect.defineProperty(obj1, "foo", undefined) },
+  TypeError);
 
 // Make sure that we can add a property with an empty descriptor and
 // that it has the default descriptor values.
-Object.defineProperty(obj1, "foo", emptyDesc);
+assertTrue(Reflect.defineProperty(obj1, "foo", emptyDesc));
 
 // foo should be undefined as it has no get, set or value
 assertEquals(undefined, obj1.foo);
 
 // We should, however, be able to retrieve the propertydescriptor which should
 // have all default values (according to 8.6.1).
 var desc = Object.getOwnPropertyDescriptor(obj1, "foo");
 assertFalse(desc.configurable);
 assertFalse(desc.enumerable);
 assertFalse(desc.writable);
 assertEquals(desc.get, undefined);
 assertEquals(desc.set, undefined);
 assertEquals(desc.value, undefined);
 
 // Make sure that getOwnPropertyDescriptor does not return a descriptor
 // with default values if called with non existing property (otherwise
 // the test above is invalid).
 desc = Object.getOwnPropertyDescriptor(obj1, "bar");
 assertEquals(desc, undefined);
 
 // Make sure that foo can't be reset (as configurable is false).
-try {
-  Object.defineProperty(obj1, "foo", accessorConfigurable);
-} catch (e) {
-  assertTrue(/Cannot redefine property/.test(e));
-}
+assertFalse(Reflect.defineProperty(obj1, "foo", accessorConfigurable));
 
 
 // Accessor properties
 
-Object.defineProperty(obj1, "bar", accessorConfigurable);
+assertTrue(Reflect.defineProperty(obj1, "bar", accessorConfigurable));
 desc = Object.getOwnPropertyDescriptor(obj1, "bar");
 assertTrue(desc.configurable);
 assertFalse(desc.enumerable);
 assertEquals(desc.writable, undefined);
 assertEquals(desc.get, accessorConfigurable.get);
 assertEquals(desc.set, accessorConfigurable.set);
 assertEquals(desc.value, undefined);
 assertEquals(1, obj1.bar = 1);
 assertEquals(1, val1);
 assertEquals(1, obj1.bar = 1);
 assertEquals(2, val1);
 assertEquals(2, obj1.bar);
 
 // Redefine bar with non configurable test
-Object.defineProperty(obj1, "bar", accessorNoConfigurable);
+assertTrue(Reflect.defineProperty(obj1, "bar", accessorNoConfigurable));
 desc = Object.getOwnPropertyDescriptor(obj1, "bar");
 assertFalse(desc.configurable);
 assertFalse(desc.enumerable);
 assertEquals(desc.writable, undefined);
 assertEquals(desc.get, accessorNoConfigurable.get);
 assertEquals(desc.set, accessorNoConfigurable.set);
 assertEquals(desc.value, undefined);
 assertEquals(1, obj1.bar = 1);
 assertEquals(2, val1);
 assertEquals(1, val2);
 assertEquals(1, obj1.bar = 1)
 assertEquals(2, val1);
 assertEquals(2, val2);
 assertEquals(2, obj1.bar);
 
 // Try to redefine bar again - should fail as configurable is false.
-try {
-  Object.defineProperty(obj1, "bar", accessorConfigurable);
-  assertTrue(false);
-} catch(e) {
-  assertTrue(/Cannot redefine property/.test(e));
-}
+assertFalse(Reflect.defineProperty(obj1, "bar", accessorConfigurable));
 
 // Try to redefine bar again using the data descriptor - should fail.
-try {
-  Object.defineProperty(obj1, "bar", dataConfigurable);
-  assertTrue(false);
-} catch(e) {
-  assertTrue(/Cannot redefine property/.test(e));
-}
+assertFalse(Reflect.defineProperty(obj1, "bar", dataConfigurable));
 
 // Redefine using same descriptor - should succeed.
-Object.defineProperty(obj1, "bar", accessorNoConfigurable);
+assertTrue(Reflect.defineProperty(obj1, "bar", accessorNoConfigurable));
 desc = Object.getOwnPropertyDescriptor(obj1, "bar");
 assertFalse(desc.configurable);
 assertFalse(desc.enumerable);
 assertEquals(desc.writable, undefined);
 assertEquals(desc.get, accessorNoConfigurable.get);
 assertEquals(desc.set, accessorNoConfigurable.set);
 assertEquals(desc.value, undefined);
 assertEquals(1, obj1.bar = 1);
 assertEquals(2, val1);
 assertEquals(3, val2);
 assertEquals(1, obj1.bar = 1)
 assertEquals(2, val1);
 assertEquals(4, val2);
 assertEquals(4, obj1.bar);
 
 // Define an accessor that has only a setter.
-Object.defineProperty(obj1, "setOnly", accessorOnlySet);
+assertTrue(Reflect.defineProperty(obj1, "setOnly", accessorOnlySet));
 desc = Object.getOwnPropertyDescriptor(obj1, "setOnly");
 assertTrue(desc.configurable);
 assertFalse(desc.enumerable);
 assertEquals(desc.set, accessorOnlySet.set);
 assertEquals(desc.writable, undefined);
 assertEquals(desc.value, undefined);
 assertEquals(desc.get, undefined);
 assertEquals(1, obj1.setOnly = 1);
 assertEquals(1, val3);
 
 // Add a getter - should not touch the setter.
-Object.defineProperty(obj1, "setOnly", accessorOnlyGet);
+assertTrue(Reflect.defineProperty(obj1, "setOnly", accessorOnlyGet));
 desc = Object.getOwnPropertyDescriptor(obj1, "setOnly");
 assertTrue(desc.configurable);
 assertFalse(desc.enumerable);
 assertEquals(desc.get, accessorOnlyGet.get);
 assertEquals(desc.set, accessorOnlySet.set);
 assertEquals(desc.writable, undefined);
 assertEquals(desc.value, undefined);
 assertEquals(1, obj1.setOnly = 1);
 assertEquals(2, val3);
 
 // The above should also work if redefining just a getter or setter on
 // an existing property with both a getter and a setter.
-Object.defineProperty(obj1, "both", accessorConfigurable);
+assertTrue(Reflect.defineProperty(obj1, "both", accessorConfigurable));
 
-Object.defineProperty(obj1, "both", accessorOnlySet);
+assertTrue(Reflect.defineProperty(obj1, "both", accessorOnlySet));
 desc = Object.getOwnPropertyDescriptor(obj1, "both");
 assertTrue(desc.configurable);
 assertFalse(desc.enumerable);
 assertEquals(desc.set, accessorOnlySet.set);
 assertEquals(desc.get, accessorConfigurable.get);
 assertEquals(desc.writable, undefined);
 assertEquals(desc.value, undefined);
 assertEquals(1, obj1.both = 1);
 assertEquals(3, val3);
 
 
 // Data properties
 
-Object.defineProperty(obj1, "foobar", dataConfigurable);
+assertTrue(Reflect.defineProperty(obj1, "foobar", dataConfigurable));
 desc = Object.getOwnPropertyDescriptor(obj1, "foobar");
 assertEquals(obj1.foobar, 1000);
 assertEquals(desc.value, 1000);
 assertTrue(desc.configurable);
 assertFalse(desc.writable);
 assertFalse(desc.enumerable);
 assertEquals(desc.get, undefined);
 assertEquals(desc.set, undefined);
 //Try writing to non writable attribute - should remain 1000
 obj1.foobar = 1001;
 assertEquals(obj1.foobar, 1000);
 
 
 // Redefine to writable descriptor - now writing to foobar should be allowed.
-Object.defineProperty(obj1, "foobar", dataWritable);
+assertTrue(Reflect.defineProperty(obj1, "foobar", dataWritable));
 desc = Object.getOwnPropertyDescriptor(obj1, "foobar");
 assertEquals(obj1.foobar, 3000);
 assertEquals(desc.value, 3000);
 // Note that since dataWritable does not define configurable the configurable
 // setting from the redefined property (in this case true) is used.
 assertTrue(desc.configurable);
 assertTrue(desc.writable);
 assertFalse(desc.enumerable);
 assertEquals(desc.get, undefined);
 assertEquals(desc.set, undefined);
 // Writing to the property should now be allowed
 obj1.foobar = 1001;
 assertEquals(obj1.foobar, 1001);
 
 
 // Redefine with non configurable data property.
-Object.defineProperty(obj1, "foobar", dataNoConfigurable);
+assertTrue(Reflect.defineProperty(obj1, "foobar", dataNoConfigurable));
 desc = Object.getOwnPropertyDescriptor(obj1, "foobar");
 assertEquals(obj1.foobar, 2000);
 assertEquals(desc.value, 2000);
 assertFalse(desc.configurable);
 assertTrue(desc.writable);
 assertFalse(desc.enumerable);
 assertEquals(desc.get, undefined);
 assertEquals(desc.set, undefined);
 
 // Try redefine again - shold fail because configurable is now false.
-try {
-  Object.defineProperty(obj1, "foobar", dataConfigurable);
-  assertTrue(false);
-} catch (e) {
-  assertTrue(/Cannot redefine property/.test(e));
-}
+assertFalse(Reflect.defineProperty(obj1, "foobar", dataConfigurable));
 
 // Try redefine again with accessor property - shold also fail.
-try {
-  Object.defineProperty(obj1, "foobar", dataConfigurable);
-  assertTrue(false);
-} catch (e) {
-  assertTrue(/Cannot redefine property/.test(e));
-}
+assertFalse(Reflect.defineProperty(obj1, "foobar", dataConfigurable));
 
 
 // Redifine with the same descriptor - should succeed (step 6).
-Object.defineProperty(obj1, "foobar", dataNoConfigurable);
+assertTrue(Reflect.defineProperty(obj1, "foobar", dataNoConfigurable));
 desc = Object.getOwnPropertyDescriptor(obj1, "foobar");
 assertEquals(obj1.foobar, 2000);
 assertEquals(desc.value, 2000);
 assertFalse(desc.configurable);
 assertTrue(desc.writable);
 assertFalse(desc.enumerable);
 assertEquals(desc.get, undefined);
 assertEquals(desc.set, undefined);
 
 
 // New object
 var obj2 = {};
 
 // Make accessor - redefine to data
-Object.defineProperty(obj2, "foo", accessorConfigurable);
+assertTrue(Reflect.defineProperty(obj2, "foo", accessorConfigurable));
 
 // Redefine to data property
-Object.defineProperty(obj2, "foo", dataConfigurable);
+assertTrue(Reflect.defineProperty(obj2, "foo", dataConfigurable));
 desc = Object.getOwnPropertyDescriptor(obj2, "foo");
 assertEquals(obj2.foo, 1000);
 assertEquals(desc.value, 1000);
 assertTrue(desc.configurable);
 assertFalse(desc.writable);
 assertFalse(desc.enumerable);
 assertEquals(desc.get, undefined);
 assertEquals(desc.set, undefined);
 
 
 // Redefine back to accessor
-Object.defineProperty(obj2, "foo", accessorConfigurable);
+assertTrue(Reflect.defineProperty(obj2, "foo", accessorConfigurable));
 desc = Object.getOwnPropertyDescriptor(obj2, "foo");
 assertTrue(desc.configurable);
 assertFalse(desc.enumerable);
 assertEquals(desc.writable, undefined);
 assertEquals(desc.get, accessorConfigurable.get);
 assertEquals(desc.set, accessorConfigurable.set);
 assertEquals(desc.value, undefined);
 assertEquals(1, obj2.foo = 1);
 assertEquals(3, val1);
 assertEquals(4, val2);
 assertEquals(3, obj2.foo);
 
 // Make data - redefine to accessor
-Object.defineProperty(obj2, "bar", dataConfigurable)
+assertTrue(Reflect.defineProperty(obj2, "bar", dataConfigurable))
 
 // Redefine to accessor property
-Object.defineProperty(obj2, "bar", accessorConfigurable);
+assertTrue(Reflect.defineProperty(obj2, "bar", accessorConfigurable));
 desc = Object.getOwnPropertyDescriptor(obj2, "bar");
 assertTrue(desc.configurable);
 assertFalse(desc.enumerable);
 assertEquals(desc.writable, undefined);
 assertEquals(desc.get, accessorConfigurable.get);
 assertEquals(desc.set, accessorConfigurable.set);
 assertEquals(desc.value, undefined);
 assertEquals(1, obj2.bar = 1);
 assertEquals(4, val1);
 assertEquals(4, val2);
 assertEquals(4, obj2.foo);
 
 // Redefine back to data property
-Object.defineProperty(obj2, "bar", dataConfigurable);
+assertTrue(Reflect.defineProperty(obj2, "bar", dataConfigurable));
 desc = Object.getOwnPropertyDescriptor(obj2, "bar");
 assertEquals(obj2.bar, 1000);
 assertEquals(desc.value, 1000);
 assertTrue(desc.configurable);
 assertFalse(desc.writable);
 assertFalse(desc.enumerable);
 assertEquals(desc.get, undefined);
 assertEquals(desc.set, undefined);
 
 
@@ skipping 12 matching lines @@
 assertEquals(desc.writable, undefined);
 assertEquals(desc.get, get);
 assertEquals(desc.set, set);
 assertEquals(desc.value, undefined);
 assertEquals(1, obj3.foo = 1);
 assertEquals(1, obj3.x);
 assertEquals(1, obj3.foo);
 
 // Redefine to accessor property (non configurable) - note that enumerable
 // which we do not redefine should remain the same (true).
-Object.defineProperty(obj3, "foo", accessorNoConfigurable);
+assertTrue(Reflect.defineProperty(obj3, "foo", accessorNoConfigurable));
 desc = Object.getOwnPropertyDescriptor(obj3, "foo");
 assertFalse(desc.configurable);
 assertTrue(desc.enumerable);
 assertEquals(desc.writable, undefined);
 assertEquals(desc.get, accessorNoConfigurable.get);
 assertEquals(desc.set, accessorNoConfigurable.set);
 assertEquals(desc.value, undefined);
 assertEquals(1, obj3.foo = 1);
 assertEquals(5, val2);
 assertEquals(5, obj3.foo);
 
 
 obj3.__defineGetter__("bar", get);
 obj3.__defineSetter__("bar", set);
 
 
 // Redefine back to data property
-Object.defineProperty(obj3, "bar", dataConfigurable);
+assertTrue(Reflect.defineProperty(obj3, "bar", dataConfigurable));
 desc = Object.getOwnPropertyDescriptor(obj3, "bar");
 assertEquals(obj3.bar, 1000);
 assertEquals(desc.value, 1000);
 assertTrue(desc.configurable);
 assertFalse(desc.writable);
 assertTrue(desc.enumerable);
 assertEquals(desc.get, undefined);
 assertEquals(desc.set, undefined);
 
 
 var obj4 = {};
 var func = function (){return 42;};
 obj4.bar = func;
 assertEquals(42, obj4.bar());
 
-Object.defineProperty(obj4, "bar", accessorConfigurable);
+assertTrue(Reflect.defineProperty(obj4, "bar", accessorConfigurable));
 desc = Object.getOwnPropertyDescriptor(obj4, "bar");
 assertTrue(desc.configurable);
 assertTrue(desc.enumerable);
 assertEquals(desc.writable, undefined);
 assertEquals(desc.get, accessorConfigurable.get);
 assertEquals(desc.set, accessorConfigurable.set);
 assertEquals(desc.value, undefined);
 assertEquals(1, obj4.bar = 1);
 assertEquals(5, val1);
 assertEquals(5, obj4.bar);
@@ skipping 54 matching lines @@
   assertTrue(/illegal access/.test(e));
 }
 
 // Test that all possible differences in step 6 in DefineOwnProperty are
 // exercised, i.e., any difference in the given property descriptor and the
 // existing properties should not return true, but throw an error if the
 // existing configurable property is false.
 
 var obj5 = {};
 // Enumerable will default to false.
-Object.defineProperty(obj5, 'foo', accessorNoConfigurable);
+assertTrue(Reflect.defineProperty(obj5, 'foo', accessorNoConfigurable));
 desc = Object.getOwnPropertyDescriptor(obj5, 'foo');
 // First, test that we are actually allowed to set the accessor if all
 // values are of the descriptor are the same as the existing one.
-Object.defineProperty(obj5, 'foo', accessorNoConfigurable);
+assertTrue(Reflect.defineProperty(obj5, 'foo', accessorNoConfigurable));
 
 // Different setter.
 var descDifferent = {
   configurable:false,
   enumerable:false,
   set: setter1,
   get: getter2
 };
 
-try {
-  Object.defineProperty(obj5, 'foo', descDifferent);
-  assertTrue(false);
-} catch (e) {
-  assertTrue(/Cannot redefine property/.test(e));
-}
+assertFalse(Reflect.defineProperty(obj5, 'foo', descDifferent));
 
 // Different getter.
 descDifferent = {
   configurable:false,
   enumerable:false,
   set: setter2,
   get: getter1
 };
 
-try {
-  Object.defineProperty(obj5, 'foo', descDifferent);
-  assertTrue(false);
-} catch (e) {
-  assertTrue(/Cannot redefine property/.test(e));
-}
+assertFalse(Reflect.defineProperty(obj5, 'foo', descDifferent));
 
 // Different enumerable.
 descDifferent = {
   configurable:false,
   enumerable:true,
   set: setter2,
   get: getter2
 };
 
-try {
-  Object.defineProperty(obj5, 'foo', descDifferent);
-  assertTrue(false);
-} catch (e) {
-  assertTrue(/Cannot redefine property/.test(e));
-}
+assertFalse(Reflect.defineProperty(obj5, 'foo', descDifferent));
 
 // Different configurable.
 descDifferent = {
   configurable:false,
   enumerable:true,
   set: setter2,
   get: getter2
 };
 
-try {
-  Object.defineProperty(obj5, 'foo', descDifferent);
-  assertTrue(false);
-} catch (e) {
-  assertTrue(/Cannot redefine property/.test(e));
-}
+assertFalse(Reflect.defineProperty(obj5, 'foo', descDifferent));
 
 // No difference.
 descDifferent = {
   configurable:false,
   enumerable:false,
   set: setter2,
   get: getter2
 };
 // Make sure we can still redefine if all properties are the same.
-Object.defineProperty(obj5, 'foo', descDifferent);
+assertTrue(Reflect.defineProperty(obj5, 'foo', descDifferent));
 
 // Make sure that obj5 still holds the original values.
 desc = Object.getOwnPropertyDescriptor(obj5, 'foo');
 assertEquals(desc.get, getter2);
 assertEquals(desc.set, setter2);
 assertFalse(desc.enumerable);
 assertFalse(desc.configurable);
 
 
 // Also exercise step 6 on data property, writable and enumerable
 // defaults to false.
-Object.defineProperty(obj5, 'bar', dataNoConfigurable);
+assertTrue(Reflect.defineProperty(obj5, 'bar', dataNoConfigurable));
 
 // Test that redefinition with the same property descriptor is possible
-Object.defineProperty(obj5, 'bar', dataNoConfigurable);
+assertTrue(Reflect.defineProperty(obj5, 'bar', dataNoConfigurable));
 
 // Different value.
 descDifferent = {
   configurable:false,
   enumerable:false,
   writable: false,
   value: 1999
 };
 
-try {
-  Object.defineProperty(obj5, 'bar', descDifferent);
-  assertTrue(false);
-} catch (e) {
-  assertTrue(/Cannot redefine property/.test(e));
-}
+assertFalse(Reflect.defineProperty(obj5, 'bar', descDifferent));
 
 // Different writable.
 descDifferent = {
   configurable:false,
   enumerable:false,
   writable: true,
   value: 2000
 };
 
-try {
-  Object.defineProperty(obj5, 'bar', descDifferent);
-  assertTrue(false);
-} catch (e) {
-  assertTrue(/Cannot redefine property/.test(e));
-}
+assertFalse(Reflect.defineProperty(obj5, 'bar', descDifferent));
 
 
 // Different enumerable.
 descDifferent = {
   configurable:false,
   enumerable:true ,
   writable:false,
   value: 2000
 };
 
-try {
-  Object.defineProperty(obj5, 'bar', descDifferent);
-  assertTrue(false);
-} catch (e) {
-  assertTrue(/Cannot redefine property/.test(e));
-}
+assertFalse(Reflect.defineProperty(obj5, 'bar', descDifferent));
 
 
 // Different configurable.
 descDifferent = {
   configurable:true,
   enumerable:false,
   writable:false,
   value: 2000
 };
 
-try {
-  Object.defineProperty(obj5, 'bar', descDifferent);
-  assertTrue(false);
-} catch (e) {
-  assertTrue(/Cannot redefine property/.test(e));
-}
+assertFalse(Reflect.defineProperty(obj5, 'bar', descDifferent));
 
 // No difference.
 descDifferent = {
   configurable:false,
   enumerable:false,
   writable:false,
   value:2000
 };
 // Make sure we can still redefine if all properties are the same.
-Object.defineProperty(obj5, 'bar', descDifferent);
+assertTrue(Reflect.defineProperty(obj5, 'bar', descDifferent));
 
 // Make sure that obj5 still holds the original values.
 desc = Object.getOwnPropertyDescriptor(obj5, 'bar');
 assertEquals(desc.value, 2000);
 assertFalse(desc.writable);
 assertFalse(desc.enumerable);
 assertFalse(desc.configurable);
 
 
 // Make sure that we can't overwrite +0 with -0 and vice versa.
 var descMinusZero = {value: -0, configurable: false};
 var descPlusZero = {value: +0, configurable: false};
 
-Object.defineProperty(obj5, 'minuszero', descMinusZero);
+assertTrue(Reflect.defineProperty(obj5, 'minuszero', descMinusZero));
 
 // Make sure we can redefine with -0.
-Object.defineProperty(obj5, 'minuszero', descMinusZero);
+assertTrue(Reflect.defineProperty(obj5, 'minuszero', descMinusZero));
 
-exception = false;
-try {
-  Object.defineProperty(obj5, 'minuszero', descPlusZero);
-} catch (e) {
-  exception = true;
-  assertTrue(/Cannot redefine property/.test(e));
-}
-assertTrue(exception);
+assertFalse(Reflect.defineProperty(obj5, 'minuszero', descPlusZero));
 
 
-Object.defineProperty(obj5, 'pluszero', descPlusZero);
+assertTrue(Reflect.defineProperty(obj5, 'pluszero', descPlusZero));
 
 // Make sure we can redefine with +0.
-Object.defineProperty(obj5, 'pluszero', descPlusZero);
+assertTrue(Reflect.defineProperty(obj5, 'pluszero', descPlusZero));
 
-exception = false;
-try {
-  Object.defineProperty(obj5, 'pluszero', descMinusZero);
-} catch (e) {
-  exception = true;
-  assertTrue(/Cannot redefine property/.test(e));
-}
-assertTrue(exception);
+assertFalse(Reflect.defineProperty(obj5, 'pluszero', descMinusZero));
 
 
 var obj6 = {};
 obj6[1] = 'foo';
 obj6[2] = 'bar';
 obj6[3] = '42';
 obj6[4] = '43';
 obj6[5] = '44';
 
 var descElement = { value: 'foobar' };
 var descElementNonConfigurable = { value: 'barfoo', configurable: false };
 var descElementNonWritable = { value: 'foofoo', writable: false };
 var descElementNonEnumerable = { value: 'barbar', enumerable: false };
 var descElementAllFalse = { value: 'foofalse',
                             configurable: false,
                             writable: false,
                             enumerable: false };
 
 
 // Redefine existing property.
-Object.defineProperty(obj6, '1', descElement);
+assertTrue(Reflect.defineProperty(obj6, '1', descElement));
 desc = Object.getOwnPropertyDescriptor(obj6, '1');
 assertEquals(desc.value, 'foobar');
 assertTrue(desc.writable);
 assertTrue(desc.enumerable);
 assertTrue(desc.configurable);
 
 // Redefine existing property with configurable: false.
-Object.defineProperty(obj6, '2', descElementNonConfigurable);
+assertTrue(Reflect.defineProperty(obj6, '2', descElementNonConfigurable));
 desc = Object.getOwnPropertyDescriptor(obj6, '2');
 assertEquals(desc.value, 'barfoo');
 assertTrue(desc.writable);
 assertTrue(desc.enumerable);
 assertFalse(desc.configurable);
 
 // Can use defineProperty to change the value of a non
 // configurable property.
 try {
-  Object.defineProperty(obj6, '2', descElement);
+  assertTrue(Reflect.defineProperty(obj6, '2', descElement));
   desc = Object.getOwnPropertyDescriptor(obj6, '2');
   assertEquals(desc.value, 'foobar');
 } catch (e) {
   assertUnreachable();
 }
 
 // Ensure that we can't change the descriptor of a
 // non configurable property.
-exception = false;
-try {
-  var descAccessor = { get: function() { return 0; } };
-  Object.defineProperty(obj6, '2', descAccessor);
-} catch (e) {
-  exception = true;
-  assertTrue(/Cannot redefine property/.test(e));
-}
-assertTrue(exception);
+var descAccessor = { get: function() { return 0; } };
+assertFalse(Reflect.defineProperty(obj6, '2', descAccessor));
 
-Object.defineProperty(obj6, '2', descElementNonWritable);
+assertTrue(Reflect.defineProperty(obj6, '2', descElementNonWritable));
 desc = Object.getOwnPropertyDescriptor(obj6, '2');
 assertEquals(desc.value, 'foofoo');
 assertFalse(desc.writable);
 assertTrue(desc.enumerable);
 assertFalse(desc.configurable);
 
-Object.defineProperty(obj6, '3', descElementNonWritable);
+assertTrue(Reflect.defineProperty(obj6, '3', descElementNonWritable));
 desc = Object.getOwnPropertyDescriptor(obj6, '3');
 assertEquals(desc.value, 'foofoo');
 assertFalse(desc.writable);
 assertTrue(desc.enumerable);
 assertTrue(desc.configurable);
 
 // Redefine existing property with configurable: false.
-Object.defineProperty(obj6, '4', descElementNonEnumerable);
+assertTrue(Reflect.defineProperty(obj6, '4', descElementNonEnumerable));
 desc = Object.getOwnPropertyDescriptor(obj6, '4');
 assertEquals(desc.value, 'barbar');
 assertTrue(desc.writable);
 assertFalse(desc.enumerable);
 assertTrue(desc.configurable);
 
 // Redefine existing property with configurable: false.
-Object.defineProperty(obj6, '5', descElementAllFalse);
+assertTrue(Reflect.defineProperty(obj6, '5', descElementAllFalse));
 desc = Object.getOwnPropertyDescriptor(obj6, '5');
 assertEquals(desc.value, 'foofalse');
 assertFalse(desc.writable);
 assertFalse(desc.enumerable);
 assertFalse(desc.configurable);
 
 // Define non existing property - all attributes should default to false.
-Object.defineProperty(obj6, '15', descElement);
+assertTrue(Reflect.defineProperty(obj6, '15', descElement));
 desc = Object.getOwnPropertyDescriptor(obj6, '15');
 assertEquals(desc.value, 'foobar');
 assertFalse(desc.writable);
 assertFalse(desc.enumerable);
 assertFalse(desc.configurable);
 
 // Make sure that we can't redefine using direct access.
 obj6[15] ='overwrite';
 assertEquals(obj6[15],'foobar');
 
@@ skipping 10 matching lines @@
 var descElementNonConfigurable = { value: 'barfoo', configurable: false };
 var descElementNonWritable = { value: 'foofoo', writable: false };
 var descElementNonEnumerable = { value: 'barbar', enumerable: false };
 var descElementAllFalse = { value: 'foofalse',
                             configurable: false,
                             writable: false,
                             enumerable: false };
 
 
 // Redefine existing property.
-Object.defineProperty(arr, '1', descElement);
+assertTrue(Reflect.defineProperty(arr, '1', descElement));
 desc = Object.getOwnPropertyDescriptor(arr, '1');
 assertEquals(desc.value, 'foobar');
 assertTrue(desc.writable);
 assertTrue(desc.enumerable);
 assertTrue(desc.configurable);
 
 // Redefine existing property with configurable: false.
-Object.defineProperty(arr, '2', descElementNonConfigurable);
+assertTrue(Reflect.defineProperty(arr, '2', descElementNonConfigurable));
 desc = Object.getOwnPropertyDescriptor(arr, '2');
 assertEquals(desc.value, 'barfoo');
 assertTrue(desc.writable);
 assertTrue(desc.enumerable);
 assertFalse(desc.configurable);
 
 // Can use defineProperty to change the value of a non
 // configurable property of an array.
 try {
-  Object.defineProperty(arr, '2', descElement);
+  assertTrue(Reflect.defineProperty(arr, '2', descElement));
   desc = Object.getOwnPropertyDescriptor(arr, '2');
   assertEquals(desc.value, 'foobar');
 } catch (e) {
   assertUnreachable();
 }
 
 // Ensure that we can't change the descriptor of a
 // non configurable property.
-exception = false;
-try {
-  var descAccessor = { get: function() { return 0; } };
-  Object.defineProperty(arr, '2', descAccessor);
-} catch (e) {
-  exception = true;
-  assertTrue(/Cannot redefine property/.test(e));
-}
-assertTrue(exception);
+var descAccessor = { get: function() { return 0; } };
+assertFalse(Reflect.defineProperty(arr, '2', descAccessor));
 
-Object.defineProperty(arr, '2', descElementNonWritable);
+assertTrue(Reflect.defineProperty(arr, '2', descElementNonWritable));
 desc = Object.getOwnPropertyDescriptor(arr, '2');
 assertEquals(desc.value, 'foofoo');
 assertFalse(desc.writable);
 assertTrue(desc.enumerable);
 assertFalse(desc.configurable);
 
-Object.defineProperty(arr, '3', descElementNonWritable);
+assertTrue(Reflect.defineProperty(arr, '3', descElementNonWritable));
 desc = Object.getOwnPropertyDescriptor(arr, '3');
 assertEquals(desc.value, 'foofoo');
 assertFalse(desc.writable);
 assertTrue(desc.enumerable);
 assertTrue(desc.configurable);
 
 // Redefine existing property with configurable: false.
-Object.defineProperty(arr, '4', descElementNonEnumerable);
+assertTrue(Reflect.defineProperty(arr, '4', descElementNonEnumerable));
 desc = Object.getOwnPropertyDescriptor(arr, '4');
 assertEquals(desc.value, 'barbar');
 assertTrue(desc.writable);
 assertFalse(desc.enumerable);
 assertTrue(desc.configurable);
 
 // Redefine existing property with configurable: false.
-Object.defineProperty(arr, '5', descElementAllFalse);
+assertTrue(Reflect.defineProperty(arr, '5', descElementAllFalse));
 desc = Object.getOwnPropertyDescriptor(arr, '5');
 assertEquals(desc.value, 'foofalse');
 assertFalse(desc.writable);
 assertFalse(desc.enumerable);
 assertFalse(desc.configurable);
 
 // Define non existing property - all attributes should default to false.
-Object.defineProperty(arr, '15', descElement);
+assertTrue(Reflect.defineProperty(arr, '15', descElement));
 desc = Object.getOwnPropertyDescriptor(arr, '15');
 assertEquals(desc.value, 'foobar');
 assertFalse(desc.writable);
 assertFalse(desc.enumerable);
 assertFalse(desc.configurable);
 
 // Define non-array property, check that .length is unaffected.
 assertEquals(16, arr.length);
-Object.defineProperty(arr, '0x20', descElement);
+assertTrue(Reflect.defineProperty(arr, '0x20', descElement));
 assertEquals(16, arr.length);
 
 // See issue 968: http://code.google.com/p/v8/issues/detail?id=968
 var o = { x : 42 };
-Object.defineProperty(o, "x", { writable: false });
+assertTrue(Reflect.defineProperty(o, "x", { writable: false }));
 assertEquals(42, o.x);
 o.x = 37;
 assertEquals(42, o.x);
 
 o = { x : 42 };
-Object.defineProperty(o, "x", {});
+assertTrue(Reflect.defineProperty(o, "x", {}));
 assertEquals(42, o.x);
 o.x = 37;
 // Writability is preserved.
 assertEquals(37, o.x);
 
 var o = { };
-Object.defineProperty(o, "x", { writable: false });
+assertTrue(Reflect.defineProperty(o, "x", { writable: false }));
 assertEquals(undefined, o.x);
 o.x = 37;
 assertEquals(undefined, o.x);
 
 o = { get x() { return 87; } };
-Object.defineProperty(o, "x", { writable: false });
+assertTrue(Reflect.defineProperty(o, "x", { writable: false }));
 assertEquals(undefined, o.x);
 o.x = 37;
 assertEquals(undefined, o.x);
 
 // Ignore inherited properties.
 o = { __proto__ : { x : 87 } };
-Object.defineProperty(o, "x", { writable: false });
+assertTrue(Reflect.defineProperty(o, "x", { writable: false }));
 assertEquals(undefined, o.x);
 o.x = 37;
 assertEquals(undefined, o.x);
 
 function testDefineProperty(obj, propertyName, desc, resultDesc) {
-  Object.defineProperty(obj, propertyName, desc);
+  assertTrue(Reflect.defineProperty(obj, propertyName, desc));
   var actualDesc = Object.getOwnPropertyDescriptor(obj, propertyName);
   assertEquals(resultDesc.enumerable, actualDesc.enumerable);
   assertEquals(resultDesc.configurable, actualDesc.configurable);
   if (resultDesc.hasOwnProperty('value')) {
     assertEquals(resultDesc.value, actualDesc.value);
     assertEquals(resultDesc.writable, actualDesc.writable);
     assertFalse(resultDesc.hasOwnProperty('get'));
     assertFalse(resultDesc.hasOwnProperty('set'));
   } else {
     assertEquals(resultDesc.get, actualDesc.get);
@@ skipping 44 matching lines @@
   { enumerable : true, configurable : false },
   { value : 42, writable : true, enumerable : true, configurable : false });
 
 o = { p : 42 };
 testDefineProperty(o, 'p',
   { enumerable : false, configurable : false },
   { value : 42, writable : true, enumerable : false, configurable : false });
 
 // can make a writable, non-configurable field non-writable
 o = { p : 42 };
-Object.defineProperty(o, 'p', { configurable: false });
+assertTrue(Reflect.defineProperty(o, 'p', { configurable: false }));
 testDefineProperty(o, 'p',
   { writable: false },
   { value : 42, writable : false, enumerable : true, configurable : false });
 
 // redefine of get only property with generic descriptor
 o = {};
-Object.defineProperty(o, 'p',
-  { get : getter1, enumerable: true, configurable: true });
+assertTrue(Reflect.defineProperty(o, 'p',
+  { get : getter1, enumerable: true, configurable: true }));
 testDefineProperty(o, 'p',
   { enumerable : false, configurable : false },
   { get: getter1, set: undefined, enumerable : false, configurable : false });
 
 // redefine of get/set only property with generic descriptor
 o = {};
-Object.defineProperty(o, 'p',
-  { get: getter1, set: setter1, enumerable: true, configurable: true });
+assertTrue(Reflect.defineProperty(o, 'p',
+  { get: getter1, set: setter1, enumerable: true, configurable: true }));
 testDefineProperty(o, 'p',
   { enumerable : false, configurable : false },
   { get: getter1, set: setter1, enumerable : false, configurable : false });
 
 // redefine of set only property with generic descriptor
 o = {};
-Object.defineProperty(o, 'p',
-  { set : setter1, enumerable: true, configurable: true });
+assertTrue(Reflect.defineProperty(o, 'p',
+  { set : setter1, enumerable: true, configurable: true }));
 testDefineProperty(o, 'p',
   { enumerable : false, configurable : false },
   { get: undefined, set: setter1, enumerable : false, configurable : false });
 
 
 // Regression test: Ensure that growing dictionaries are not ignored.
 o = {};
 for (var i = 0; i < 1000; i++) {
   // Non-enumerable property forces dictionary mode.
-  Object.defineProperty(o, i, {value: i, enumerable: false});
+  assertTrue(Reflect.defineProperty(o, i, {value: i, enumerable: false}));
 }
 assertEquals(999, o[999]);
 
 
 // Regression test: Bizzare behavior on non-strict arguments object.
 // TODO(yangguo): Tests disabled, needs investigation!
 /*
 (function test(arg0) {
   // Here arguments[0] is a fast alias on arg0.
-  Object.defineProperty(arguments, "0", {
+  Reflect.defineProperty(arguments, "0", {
     value:1,
     enumerable:false
   });
   // Here arguments[0] is a slow alias on arg0.
-  Object.defineProperty(arguments, "0", {
+  Reflect.defineProperty(arguments, "0", {
     value:2,
     writable:false
   });
   // Here arguments[0] is no alias at all.
-  Object.defineProperty(arguments, "0", {
+  Reflect.defineProperty(arguments, "0", {
     value:3
   });
   assertEquals(2, arg0);
   assertEquals(3, arguments[0]);
 })(0);
 */
 
 // Regression test: We should never observe the hole value.
 var objectWithGetter = {};
 objectWithGetter.__defineGetter__('foo', function() {});
 assertEquals(undefined, objectWithGetter.__lookupSetter__('foo'));
 
 var objectWithSetter = {};
 objectWithSetter.__defineSetter__('foo', function(x) {});
 assertEquals(undefined, objectWithSetter.__lookupGetter__('foo'));
 
 // An object with a getter on the prototype chain.
 function getter() { return 111; }
 function anotherGetter() { return 222; }
 
 function testGetterOnProto(expected, o) {
   assertEquals(expected, o.quebec);
 }
 
 obj1 = {};
-Object.defineProperty(obj1, "quebec", { get: getter, configurable: true });
+assertTrue(
+  Reflect.defineProperty(obj1, "quebec", { get: getter, configurable: true }));
 obj2 = Object.create(obj1);
 obj3 = Object.create(obj2);
 
 testGetterOnProto(111, obj3);
 testGetterOnProto(111, obj3);
 %OptimizeFunctionOnNextCall(testGetterOnProto);
 testGetterOnProto(111, obj3);
 testGetterOnProto(111, obj3);
 
-Object.defineProperty(obj1, "quebec", { get: anotherGetter });
+assertTrue(Reflect.defineProperty(obj1, "quebec", { get: anotherGetter }));
 
 testGetterOnProto(222, obj3);
 testGetterOnProto(222, obj3);
 %OptimizeFunctionOnNextCall(testGetterOnProto);
 testGetterOnProto(222, obj3);
 testGetterOnProto(222, obj3);
 
 // An object with a setter on the prototype chain.
 var modifyMe;
 function setter(x) { modifyMe = x+1; }
 function anotherSetter(x) { modifyMe = x+2; }
 
 function testSetterOnProto(expected, o) {
   modifyMe = 333;
   o.romeo = 444;
   assertEquals(expected, modifyMe);
 }
 
 obj1 = {};
-Object.defineProperty(obj1, "romeo", { set: setter, configurable: true });
+assertTrue(
+  Reflect.defineProperty(obj1, "romeo", { set: setter, configurable: true }));
 obj2 = Object.create(obj1);
 obj3 = Object.create(obj2);
 
 testSetterOnProto(445, obj3);
 testSetterOnProto(445, obj3);
 %OptimizeFunctionOnNextCall(testSetterOnProto);
 testSetterOnProto(445, obj3);
 testSetterOnProto(445, obj3);
 
-Object.defineProperty(obj1, "romeo", { set: anotherSetter });
+assertTrue(Reflect.defineProperty(obj1, "romeo", { set: anotherSetter }));
 
 testSetterOnProto(446, obj3);
 testSetterOnProto(446, obj3);
 %OptimizeFunctionOnNextCall(testSetterOnProto);
 testSetterOnProto(446, obj3);
 testSetterOnProto(446, obj3);
 
 // Removing a setter on the prototype chain.
 function testSetterOnProtoStrict(o) {
   "use strict";
   o.sierra = 12345;
 }
 
 obj1 = {};
-Object.defineProperty(obj1, "sierra",
-                      { get: getter, set: setter, configurable: true });
+assertTrue(Reflect.defineProperty(obj1, "sierra",
+                      { get: getter, set: setter, configurable: true }));
 obj2 = Object.create(obj1);
 obj3 = Object.create(obj2);
 
 testSetterOnProtoStrict(obj3);
 testSetterOnProtoStrict(obj3);
 %OptimizeFunctionOnNextCall(testSetterOnProtoStrict);
 testSetterOnProtoStrict(obj3);
 testSetterOnProtoStrict(obj3);
 
-Object.defineProperty(obj1, "sierra",
-                      { get: getter, set: undefined, configurable: true });
+assertTrue(Reflect.defineProperty(obj1, "sierra",
+                      { get: getter, set: undefined, configurable: true }));
 
 exception = false;
 try {
   testSetterOnProtoStrict(obj3);
 } catch (e) {
   exception = true;
   assertTrue(/which has only a getter/.test(e));
 }
 assertTrue(exception);
 
 // Test assignment to a getter-only property on the prototype chain. This makes
 // sure that crankshaft re-checks its assumptions and doesn't rely only on type
 // feedback (which would be monomorphic here).
 
 function Assign(o) {
   o.blubb = 123;
 }
 
 function C() {}
 
 Assign(new C);
 Assign(new C);
 %OptimizeFunctionOnNextCall(Assign);
-Object.defineProperty(C.prototype, "blubb", {get: function() { return -42; }});
+assertTrue(
+  Reflect.defineProperty(C.prototype, "blubb", {get: function() {return -42}}));
 Assign(new C);
 
 // Test that changes to the prototype of a simple constructor are not ignored,
 // even after creating initial instances.
 function C() {
   this.x = 23;
 }
 assertEquals(23, new C().x);
 C.prototype.__defineSetter__('x', function(value) { this.y = 23; });
 assertEquals(void 0, new C().x);