Add tests for setting/defining an element of a typed array to a value, where...

Add tests for setting/defining an element of a typed array to a value, where converting that value to the typed array element type detaches the buffer underlying the typed array. (#1336)

test/built-ins/TypedArrays/internals/DefineOwnProperty/tonumber-value-detached-buffer.js

+// Copyright (C) 2017 Mozilla Corporation. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-integer-indexed-exotic-objects-defineownproperty-p-desc
+description: >
+    Defining a typed array element to a value that, when converted to the typed
+    array element type, detaches the typed array's underlying buffer, should
+    throw a TypeError and not modify the typed array.
+info: >
+  9.4.5.3 [[DefineOwnProperty]] ( P, Desc )
+
+  ...
+  3. If Type(P) is String, then
+    a. Let numericIndex be ! CanonicalNumericIndexString(P).
+    b. If numericIndex is not undefined, then
+      ...
+      x. If Desc has a [[Value]] field, then
+        1. Let value be Desc.[[Value]].
+        2. Return ? IntegerIndexedElementSet(O, numericIndex, value).
+  ...
+
+  9.4.5.9 IntegerIndexedElementSet ( O, index, value )
+
+  ...
+  15. Perform SetValueInBuffer(buffer, indexedPosition, elementType, numValue).
+  16. Return true.
+includes: [testTypedArray.js, detachArrayBuffer.js]
+features: [Reflect, TypedArray]
+---*/
+
+testWithTypedArrayConstructors(function(TA) {
+  var ta = new TA([17]);
+
+  var desc =
+    {
+      value: {
+        valueOf: function() {
+          $262.detachArrayBuffer(ta.buffer);
+          return 42;
+        }
+      }
+    };
+
+  assert.throws(TypeError, function() {
+    Reflect.defineProperty(ta, 0, desc);
+  },
+  "detaching a ArrayBuffer during defining an element of a typed array " +
+  "viewing it should throw");
+
+  assert.sameValue(ta[0], 17, "typed array element shouldn't be set");
+});
+

test/built-ins/TypedArrays/internals/Set/tonumber-value-detached-buffer.js

+// Copyright (C) 2017 Mozilla Corporation. All rights reserved.
+// This code is governed by the BSD license found in the LICENSE file.
+
+/*---
+esid: sec-integer-indexed-exotic-objects-set-p-v-receiver
+description: >
+    Setting a typed array element to a value that, when converted to the typed
+    array element type, detaches the typed array's underlying buffer, should
+    throw a TypeError and not modify the typed array.
+info: >
+  9.4.5.5 [[Set]] ( P, V, Receiver)
+
+  ...
+  2. If Type(P) is String, then
+    a. Let numericIndex be ! CanonicalNumericIndexString(P).
+    b. If numericIndex is not undefined, then
+      i. Return ? IntegerIndexedElementSet(O, numericIndex, V).
+  ...
+
+  9.4.5.9 IntegerIndexedElementSet ( O, index, value )
+
+  ...
+  15. Perform SetValueInBuffer(buffer, indexedPosition, elementType, numValue).
+  16. Return true.
+includes: [testTypedArray.js, detachArrayBuffer.js]
+features: [Reflect, TypedArray]
+---*/
+
+testWithTypedArrayConstructors(function(TA) {
+  var ta = new TA([17]);
+
+  assert.throws(TypeError, function() {
+    Reflect.set(ta, 0, {
+      valueOf: function() {
+        $262.detachArrayBuffer(ta.buffer);
+        return 42;
+      }
+    });
+  },
+  "detaching a ArrayBuffer during setting an element of a typed array " +
+  "viewing it should throw");
+
+  assert.sameValue(ta[0], 17, "typed array element shouldn't be set");
+});