Declare Memcached as impure

Author: VincentLanglet

stubs/Memcached.stub

@@ -0,0 +1,6 @@
+<?php
+
+/**
+ * @phpstan-all-methods-impure
+ */
+class Memcached {}

tests/PHPStan/Rules/Comparison/StrictComparisonOfDifferentTypesRuleTest.php

@@ -1197,6 +1197,11 @@ public function testBug14446(): void
 		$this->analyse([__DIR__ . '/../../Analyser/data/bug-14446.php'], []);
 	}
 
+	public function testBug13444(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-13444.php'], []);
+	}
+
 	public function testBug14473(): void
 	{
 		$this->analyse([__DIR__ . '/data/bug-14519.php'], []);

tests/PHPStan/Rules/Comparison/data/bug-13444.php

@@ -0,0 +1,28 @@
+<?php declare(strict_types = 1);
+
+namespace Bug13444;
+
+function sayStoreCas(string $key): void
+{
+	$memcached = new \Memcached();
+
+	do {
+		$extendedReturn = $memcached->get($key, null, \Memcached::GET_EXTENDED);
+
+		if ($memcached->getResultCode() !== \Memcached::RES_SUCCESS) {
+			return;
+		}
+
+		if (!is_array($extendedReturn) || !isset($extendedReturn['value']) || !isset($extendedReturn['cas'])) {
+			return;
+		}
+
+		$data = $extendedReturn['value'];
+		$cas = $extendedReturn['cas'];
+		\assert(is_float($cas));
+
+		// Do some work on the data..
+		$memcached->cas($cas, $key, $data);
+
+	} while ($memcached->getResultCode() !== \Memcached::RES_SUCCESS);
+}