Regression tests

Closes phpstan/phpstan#5337

tests/PHPStan/Rules/DeadCode/UnusedPrivatePropertyRuleTest.php

@@ -230,4 +230,26 @@ public function testBug5935(): void
 		$this->analyse([__DIR__ . '/data/bug-5935.php'], []);
 	}
 
+	public function testBug5337(): void
+	{
+		if (PHP_VERSION_ID < 70400 && !self::$useStaticReflectionProvider) {
+			$this->markTestSkipped('Test requires PHP 7.4.');
+		}
+
+		$this->alwaysWrittenTags = [];
+		$this->alwaysReadTags = [];
+		$this->analyse([__DIR__ . '/data/bug-5337.php'], [
+			[
+				'Property Bug5337\Clazz::$prefix is never read, only written.',
+				7,
+				'See: https://phpstan.org/developing-extensions/always-read-written-properties',
+			],
+			[
+				'Property Bug5337\Foo::$field is unused.',
+				20,
+				'See: https://phpstan.org/developing-extensions/always-read-written-properties',
+			],
+		]);
+	}
+
 }

tests/PHPStan/Rules/DeadCode/data/bug-5337.php

@@ -0,0 +1,27 @@
+<?php // lint >= 7.4
+
+namespace Bug5337;
+
+class Clazz
+{
+	private ?string $prefix;
+
+	public function setter(string $prefix): void
+	{
+		if (!empty($this->prefix)) {
+			$this->prefix = $prefix;
+		}
+	}
+}
+
+class Foo
+{
+
+	private string $field;
+
+	public function __construct()
+	{
+		if (isset($this->field)) {}
+	}
+
+}