diff --git a/tests/PHPStan/Analyser/nsrt/bug-14249.php b/tests/PHPStan/Analyser/nsrt/bug-14249.php
index f3408725b6..0d4cd00c4c 100644
--- a/tests/PHPStan/Analyser/nsrt/bug-14249.php
+++ b/tests/PHPStan/Analyser/nsrt/bug-14249.php
@@ -69,6 +69,7 @@ function doTemplated(): void {
 	assertType('false', $v);
 }
 
+/** @phpstan-impure */
 function getMixed(): mixed {}
 
 function maybeCallable() {