Added regression test

Author: staabm

tests/PHPStan/Rules/Methods/ReturnTypeRuleTest.php

@@ -1259,4 +1259,10 @@ public function testBug12928(): void
 		]);
 	}
 
+	#[RequiresPhp('>= 8.0')]
+	public function testBug7225(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-7225.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Methods/data/bug-7225.php

@@ -0,0 +1,18 @@
+<?php // lint >= 8.0
+
+namespace Bug7225;
+
+use DateTimeImmutable;
+
+class CustomDateTimeImmutable extends DateTimeImmutable
+{
+	public function test(): self
+	{
+		return CustomDateTimeImmutable::createFromInterface(new DateTime());
+	}
+
+	public function fromFormat(): CustomDateTimeImmutable|false
+	{
+		return CustomDateTimeImmutable::createFromFormat('H:i:s', '00:00:00');
+	}
+}