Regression tests

Closes phpstan/phpstan#12553

Author: ondrejmirtes

tests/PHPStan/Rules/Properties/WritingToReadOnlyPropertiesRuleTest.php

@@ -107,4 +107,14 @@ public function testPropertyHooks(): void
 		]);
 	}
 
+	public function testBug12553(): void
+	{
+		if (PHP_VERSION_ID < 80400) {
+			$this->markTestSkipped('Test requires PHP 8.4.');
+		}
+
+		$this->checkThisOnly = false;
+		$this->analyse([__DIR__ . '/../Variables/data/bug-12553.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Variables/NullCoalesceRuleTest.php

@@ -346,4 +346,14 @@ public function testBug10610(): void
 		$this->analyse([__DIR__ . '/data/bug-10610.php'], []);
 	}
 
+	public function testBug12553(): void
+	{
+		if (PHP_VERSION_ID < 80400) {
+			$this->markTestSkipped('Test requires PHP 8.4.');
+		}
+
+		$this->treatPhpDocTypesAsCertain = true;
+		$this->analyse([__DIR__ . '/data/bug-12553.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Variables/data/bug-12553.php

@@ -0,0 +1,22 @@
+<?php
+
+namespace Bug12553;
+
+interface TimestampsInterface
+{
+	public \DateTimeImmutable $createdAt { get; }
+}
+
+trait Timestamps
+{
+	public private(set) \DateTimeImmutable $createdAt {
+		get {
+			return $this->createdAt ??= new \DateTimeImmutable();
+		}
+	}
+}
+
+class Example implements TimestampsInterface
+{
+	use Timestamps;
+}