diff --git a/src/Symfony/Component/ErrorHandler/DebugClassLoader.php b/src/Symfony/Component/ErrorHandler/DebugClassLoader.php
index d5e81052ce6f3..5db2f30a1c7b4 100644
--- a/src/Symfony/Component/ErrorHandler/DebugClassLoader.php
+++ b/src/Symfony/Component/ErrorHandler/DebugClassLoader.php
@@ -1097,7 +1097,7 @@ private function fixReturnStatements(\ReflectionMethod $method, string $returnTy
         $braces = 0;
         for (; $i < $end; ++$i) {
             if (!$inClosure) {
-                $inClosure = str_contains($code[$i], 'function (');
+                $inClosure = false !== strpos($code[$i], 'function (');
             }
 
             if ($inClosure) {
diff --git a/src/Symfony/Component/ErrorHandler/ErrorHandler.php b/src/Symfony/Component/ErrorHandler/ErrorHandler.php
index d7b90439a5a5c..28b93c2b158b7 100644
--- a/src/Symfony/Component/ErrorHandler/ErrorHandler.php
+++ b/src/Symfony/Component/ErrorHandler/ErrorHandler.php
@@ -457,7 +457,7 @@ public function handleError(int $type, string $message, string $file, int $line)
                 return true;
             }
         } else {
-            if (false !== strpos($message, '@anonymous')) {
+            if (PHP_VERSION_ID < 80303 && false !== strpos($message, '@anonymous')) {
                 $backtrace = debug_backtrace(false, 5);
 
                 for ($i = 1; isset($backtrace[$i]); ++$i) {
@@ -465,8 +465,7 @@ public function handleError(int $type, string $message, string $file, int $line)
                         && ('trigger_error' === $backtrace[$i]['function'] || 'user_error' === $backtrace[$i]['function'])
                     ) {
                         if ($backtrace[$i]['args'][0] !== $message) {
-                            $message = $this->parseAnonymousClass($backtrace[$i]['args'][0]);
-                            $logMessage = $this->levels[$type].': '.$message;
+                            $message = $backtrace[$i]['args'][0];
                         }
 
                         break;
@@ -474,6 +473,11 @@ public function handleError(int $type, string $message, string $file, int $line)
                 }
             }
 
+            if (false !== strpos($message, "@anonymous\0")) {
+                $message = $this->parseAnonymousClass($message);
+                $logMessage = $this->levels[$type].': '.$message;
+            }
+
             $errorAsException = new \ErrorException($logMessage, 0, $type, $file, $line);
 
             if ($throw || $this->tracedErrors & $type) {