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/*
* If the Array.prototype contains numeric elements which are write protected
* (but configurable), it should be possible to create an array literal with
* an overriding value. A normal property assignment would fail because the
* inherited property is not writable. An array initializer is supposed to
* use [[DefineOwnProperty]] which allows an own property to be created even
* if there is an inherited property which would normally prevent a write.
*/
/*===
defineProperty success
0 inherit undefined
2 foo bar
0 inherit undefined
2 shouldsucceed bar
===*/
function test() {
var arr;
Object.defineProperty(Array.prototype,
'0',
{
value: 'inherit',
writable: false,
enumerable: true,
configurable: true
});
print('defineProperty success');
// No problem here: '0' not accessed
arr = [];
print(arr.length, arr[0], arr[1]);
// Again should succeed
var arr = ['foo', 'bar'];
print(arr.length, arr[0], arr[1]);
// Assignment should not work unless an own property already exists
arr = [];
arr[0] = 'shouldfail'; // failure is silent
print(arr.length, arr[0], arr[1]);
arr = ['foo', 'bar'];
arr[0] = 'shouldsucceed';
print(arr.length, arr[0], arr[1]);
}
try {
test();
} catch (e) {
print(e);
}