add 5551 test

Author: mvorisek

tests/PHPStan/Rules/Properties/TypesAssignedToPropertiesRuleTest.php

@@ -271,6 +271,11 @@ public function testAppendendArrayKey(): void
 		]);
 	}
 
+	public function testBug5551(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-5551.php'], []);
+	}
+
 	public function testBug5372Two(): void
 	{
 		$this->analyse([__DIR__ . '/../Arrays/data/bug-5372_2.php'], []);

tests/PHPStan/Rules/Properties/data/bug-5551.php

@@ -0,0 +1,22 @@
+<?php
+
+namespace Bug5551;
+
+class Foo
+{
+	/**
+	 * @var WeakMap<\stdClass, \stdClass>
+	 */
+	protected static WeakMap $bug;
+
+	/**
+	 * @var WeakMap<\stdClass, \stdClass>
+	 */
+	protected WeakMap $ok;
+
+	public function bug(): void
+	{
+		$this->ok = new WeakMap();
+		static::$bug = new WeakMap();
+	}
+}