Added regression test

Author: staabm

tests/PHPStan/Rules/Methods/ReturnTypeRuleTest.php

@@ -993,4 +993,9 @@ public function testBug10291(): void
 		$this->analyse([__DIR__ . '/data/bug-10291.php'], []);
 	}
 
+	public function testBug5008(): void
+	{
+		$this->analyse([__DIR__ . '/data/bug-5008.php'], []);
+	}
+
 }

tests/PHPStan/Rules/Methods/data/bug-5008.php

@@ -0,0 +1,14 @@
+<?php declare(strict_types = 1);
+
+namespace Bug5008;
+
+class SomeHelper
+{
+	/**
+	 * @return -1|0|1
+	 */
+	public static function f(int $a, int $b): int
+	{
+		return $a <=> $b;
+	}
+}