Fix another corner-case behavior of Object::SetSuperProperty.

test/mjsunit/es6/super.js

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // Flags: --allow-natives-syntax
 // Flags: --harmony-destructuring --harmony-rest-parameters --harmony-sloppy
 
 (function TestSuperNamedLoads() {
   function Base() { }
   function fBase() { }
@@ skipping 921 matching lines @@
 
 
 (function TestSetterCreatingOwnPropertiesReconfigurable() {
   function Base() {}
   function Derived() {}
   Derived.prototype = {
     __proto__: Base.prototype,
     mSloppy() {
       assertEquals(42, this.ownReadOnly);
       super.ownReadOnly = 55;
-      assertEquals(55, this.ownReadOnly);
-      var descr = Object.getOwnPropertyDescriptor(this, 'ownReadOnly');
-      assertEquals(55, descr.value);
-      assertTrue(descr.configurable);
-      assertFalse(descr.enumerable);
-      assertFalse(descr.writable);
+      assertSame(undefined, super.ownReadOnly);
+      assertEquals(42, this.ownReadOnly);
       assertFalse(Base.prototype.hasOwnProperty('ownReadOnly'));
 
       assertEquals(15, this.ownReadonlyAccessor);
       super.ownReadonlyAccessor = 25;
       assertSame(undefined, super.ownReadonlyAccessor);
       assertEquals(15, this.ownReadonlyAccessor);
       assertFalse(Base.prototype.hasOwnProperty('ownReadonlyAccessor'));
 
       super.ownSetter = 35;
       assertSame(undefined, super.ownSetter);
       var descr = Object.getOwnPropertyDescriptor(this, 'ownSetter');
       assertTrue('set' in descr);
       assertFalse(Base.prototype.hasOwnProperty('ownSetter'));
     },
     mStrict() {
       'use strict';
       assertEquals(42, this.ownReadOnly);
-      super.ownReadOnly = 55;
-      assertEquals(55, this.ownReadOnly);
-      var descr = Object.getOwnPropertyDescriptor(this, 'ownReadOnly');
-      assertEquals(55, descr.value);
-      assertTrue(descr.configurable);
-      assertFalse(descr.enumerable);
-      assertFalse(descr.writable);
+      assertThrows(() => {super.ownReadOnly = 55}, TypeError);
+      assertSame(undefined, super.ownReadOnly);
+      assertEquals(42, this.ownReadOnly);
       assertFalse(Base.prototype.hasOwnProperty('ownReadOnly'));
 
       assertEquals(15, this.ownReadonlyAccessor);
       assertThrows(() => {super.ownReadonlyAccessor = 25}, TypeError);
       assertSame(undefined, super.ownReadonlyAccessor);
       assertEquals(15, this.ownReadonlyAccessor);
       assertFalse(Base.prototype.hasOwnProperty('ownReadonlyAccessor'));
 
       assertThrows(() => {super.ownSetter = 35}, TypeError);
       assertSame(undefined, super.ownSetter);
@@ skipping 178 matching lines @@
 
 function TestKeyedSetterCreatingOwnPropertiesReconfigurable(ownReadOnly,
     ownReadonlyAccessor, ownSetter) {
   function Base() {}
   function Derived() {}
   Derived.prototype = {
     __proto__: Base.prototype,
     mSloppy() {
       assertEquals(42, this[ownReadOnly]);
       super[ownReadOnly] = 55;
-      assertEquals(55, this[ownReadOnly]);
-      var descr = Object.getOwnPropertyDescriptor(this, ownReadOnly);
-      assertEquals(55, descr.value);
-      assertTrue(descr.configurable);
-      assertFalse(descr.enumerable);
-      assertFalse(descr.writable);
+      assertSame(undefined, super[ownReadOnly]);
+      assertEquals(42, this[ownReadOnly]);
       assertFalse(Base.prototype.hasOwnProperty(ownReadOnly));
 
       assertEquals(15, this[ownReadonlyAccessor]);
       super[ownReadonlyAccessor] = 25;
       assertSame(undefined, super[ownReadonlyAccessor]);
       assertEquals(15, this[ownReadonlyAccessor]);
       assertFalse(Base.prototype.hasOwnProperty(ownReadonlyAccessor));
 
       super[ownSetter] = 35;
       assertSame(undefined, super[ownSetter]);
       var descr = Object.getOwnPropertyDescriptor(this, ownSetter);
       assertTrue('set' in descr);
       assertFalse(Base.prototype.hasOwnProperty(ownSetter));
     },
     mStrict() {
       'use strict';
       assertEquals(42, this[ownReadOnly]);
-      super[ownReadOnly] = 55;
-      assertEquals(55, this[ownReadOnly]);
-      var descr = Object.getOwnPropertyDescriptor(this, ownReadOnly);
-      assertEquals(55, descr.value);
-      assertTrue(descr.configurable);
-      assertFalse(descr.enumerable);
-      assertFalse(descr.writable);
+      assertThrows(() => {super[ownReadOnly] = 55}, TypeError);
+      assertSame(undefined, super[ownReadOnly]);
+      assertEquals(42, this[ownReadOnly]);
       assertFalse(Base.prototype.hasOwnProperty(ownReadOnly));
 
       assertEquals(15, this[ownReadonlyAccessor]);
       assertThrows(() => {super[ownReadonlyAccessor] = 25}, TypeError);
       assertSame(undefined, super[ownReadonlyAccessor]);
       assertEquals(15, this[ownReadonlyAccessor]);
       assertFalse(Base.prototype.hasOwnProperty(ownReadonlyAccessor));
 
       assertThrows(() => {super[ownSetter] = 35}, TypeError);
       assertSame(undefined, super[ownSetter]);
@@ skipping 1013 matching lines @@
   }
   class Derived extends Base {
     constructor(x) {
       let r = (() => super(...[x]))();
       assertEquals(this, r);
     }
   }
   let d = new Derived(42);
   assertSame(42, d.x);
 })();