1--TEST--
2SplFixedArray properties is incompatible with ArrayObject
3--FILE--
4<?php
5$ao = new ArrayObject([1, 2, 3]);
6$fixedArray = new SplFixedArray(1);
7$fixedArray[0] = new SplDoublyLinkedList();
8try {
9  // See GH-15918: this *should* fail to not break invariants
10  $ao->exchangeArray($fixedArray);
11} catch (InvalidArgumentException $e) {
12  echo $e->getMessage(), "\n";
13}
14?>
15--EXPECT--
16Overloaded object of type SplFixedArray is not compatible with ArrayObject
17