diff --git a/src/Type/Php/DateIntervalDynamicReturnTypeExtension.php b/src/Type/Php/DateIntervalDynamicReturnTypeExtension.php
index 90842b37a0..a59b975746 100644
--- a/src/Type/Php/DateIntervalDynamicReturnTypeExtension.php
+++ b/src/Type/Php/DateIntervalDynamicReturnTypeExtension.php
@@ -1,4 +1,4 @@
-<?php declare( strict_types = 1 );
+<?php declare(strict_types = 1);
 
 namespace PHPStan\Type\Php;
 
diff --git a/tests/PHPStan/Analyser/data/bug-8442.php b/tests/PHPStan/Analyser/data/bug-8442.php
index 64ed0e6653..96005d7d85 100644
--- a/tests/PHPStan/Analyser/data/bug-8442.php
+++ b/tests/PHPStan/Analyser/data/bug-8442.php
@@ -34,6 +34,7 @@ function () {
 
 	assertType('false', DateInterval::createFromDateString($interval));
 
+	assertType('DateInterval|false',DateInterval::createFromDateString(str_shuffle('1 day')));
 	assertType('DateInterval|false',DateInterval::createFromDateString());
 	assertType('DateInterval|false',DateInterval::createFromDateString(new stdClass()));
 };