Add test for InvalidComparisonOperationRule for offset accessing SimpleXMLElement.

Author: mad-briller

tests/PHPStan/Rules/Operators/InvalidComparisonOperationRuleTest.php

@@ -168,4 +168,10 @@ public function testRuleWithNullsafeVariant(): void
 ]);
 }
 
+
+public function testRuleWithSimpleXml(): void
+{
+$this->analyse([__DIR__ . '/data/bug-9456-xml.php'], []);
+}
+
 }

tests/PHPStan/Rules/Operators/data/bug-9456-xml.php

@@ -0,0 +1,19 @@
+<?php
+
+namespace Bug9456Xml;
+
+use SimpleXMLElement;
+
+/**
+ * @param SimpleXMLElement $xml
+ */
+function simplexml($xml): void
+{
+if (isset($xml->modules)) {
+foreach ($xml->modules->module as $data) {
+/** @var SimpleXMLElement $data */
+$attributes = $data->attributes();
+$install = ($attributes['install'] == 1) ? true : false;
+}
+}
+}