From 2aa6c21bba1416f8611837845cb40ee0b5da03fe Mon Sep 17 00:00:00 2001
From: azjezz <azjezz@protonmail.com>
Date: Thu, 10 Nov 2022 19:57:54 +0100
Subject: [PATCH] Revert "fix: don't close argument type. (#7)"

This reverts commit 1c425b71c6d9df6d5058c985d2128a9e2d3c0c09.
---
 .../Type/Optional/FunctionReturnTypeProvider.php             | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/src/EventHandler/Type/Optional/FunctionReturnTypeProvider.php b/src/EventHandler/Type/Optional/FunctionReturnTypeProvider.php
index 896f434..2c0fbb3 100644
--- a/src/EventHandler/Type/Optional/FunctionReturnTypeProvider.php
+++ b/src/EventHandler/Type/Optional/FunctionReturnTypeProvider.php
@@ -28,6 +28,9 @@ final class FunctionReturnTypeProvider implements FunctionReturnTypeProviderInte
             return null;
         }
 
-        return $argument_type->setPossiblyUndefined(true);
+        $clone = clone $argument_type;
+        $clone->possibly_undefined = true;
+
+        return $clone;
     }
 }