Add %TypedArray% to proto chain

test/mjsunit/es6/built-in-accessor-names.js

 // Copyright 2015 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: --harmony-tostring
 
 'use strict';
 
-function assertGetterName(expected, object, name) {
-  var descr = Object.getOwnPropertyDescriptor(object, name);
+function GetPropertyDescriptor(object, field, indirect) {
+  if (!indirect)
+    return Object.getOwnPropertyDescriptor(object, field);
+  var descriptor;
+  while (descriptor === undefined && object !== Object.prototype) {
+    descriptor = Object.getOwnPropertyDescriptor(object, field);
+    object = object.__proto__;
+  }
+  return descriptor;
+}
+
+function assertGetterName(expected, object, name, indirect) {
+  var descr = GetPropertyDescriptor(object, name, indirect);
   assertSame(expected, descr.get.name);
 }
 
 
-function assertSetterName(expected, object, name) {
-  var descr = Object.getOwnPropertyDescriptor(object, name);
+function assertSetterName(expected, object, name, indirect) {
+  var descr = GetPropertyDescriptor(object, name);
   assertSame(expected, descr.set.name);
 }
 
 
 assertGetterName('get byteLength', ArrayBuffer.prototype, 'byteLength');
 assertGetterName('get size', Set.prototype, 'size');
 assertGetterName('get size', Map.prototype, 'size');
 
 
 let typedArrays = [
   Uint8Array,
   Int8Array,
   Uint16Array,
   Int16Array,
   Uint32Array,
   Int32Array,
   Float32Array,
   Float64Array,
   Uint8ClampedArray
 ];
 
 for (let f of typedArrays) {
-  assertGetterName('get buffer', f.prototype, 'buffer');
-  assertGetterName('get byteOffset', f.prototype, 'byteOffset');
-  assertGetterName('get byteLength', f.prototype, 'byteLength');
-  assertGetterName('get length', f.prototype, 'length');
-  assertGetterName('get [Symbol.toStringTag]', f.prototype, Symbol.toStringTag);
+  assertGetterName('get buffer', f.prototype, 'buffer', true);

[adamk, 2015/06/13 00:49:38]

Wouldn't this work with the old code just changed to:

assertGetterName('get buffer', f.prototype.__proto__, 'buffer')

The imprecision of GetPropertyDescriptor's proto chain walk seems bad to me.

[Dan Ehrenberg, 2015/06/13 05:54:09]

I thought it was nicer to do the proto walk because if something came along
later and shadowed that property, then that'd show up instead. I'll change this
to a numerical parameter for which level in the chain to check for, and assert
that it doesn't exist lower.

+  assertGetterName('get byteOffset', f.prototype, 'byteOffset', true);
+  assertGetterName('get byteLength', f.prototype, 'byteLength', true);
+  assertGetterName('get length', f.prototype, 'length', true);
+  assertGetterName('get [Symbol.toStringTag]', f.prototype, Symbol.toStringTag, true);
 }
 
 
 assertGetterName('get buffer', DataView.prototype, 'buffer');
 assertGetterName('get byteOffset', DataView.prototype, 'byteOffset');
 assertGetterName('get byteLength', DataView.prototype, 'byteLength');
 
 
 assertGetterName('get __proto__', Object.prototype, '__proto__');
 assertSetterName('set __proto__', Object.prototype, '__proto__');