Deprecate CmsRouter toString method for objects

src/Routing/CmsRouter.php

@@ -49,7 +49,13 @@ public function getRouteCollection(): RouteCollection
     public function generate(string $name, array $parameters = [], int $referenceType = self::ABSOLUTE_PATH): string
     {
         // prevent error with symfony/router >= 5.4 and doctrine proxies
-        $parameters = array_map(fn ($value) => $value instanceof Proxy && method_exists($value, '__toString') ? $value->__toString() : $value, $parameters);
+        $parameters = array_map(function ($value) {
+            if (is_object($value) && method_exists($value, '__toString')) {
+                trigger_error('Using objects with __toString as parameters is deprecated since softspring/cms-bundle 5.2 and will be removed in 6.0. Use the specific id field.', E_USER_DEPRECATED);
+            }
+
+            return $value instanceof Proxy && method_exists($value, '__toString') ? $value->__toString() : $value;
+        }, $parameters);
 
         try {
             $cleanParams = array_filter($parameters, fn ($key) => !in_array($key, ['_sfs_cms_locale', '_sfs_cms_locale_path']), ARRAY_FILTER_USE_KEY);