diff --git a/scrapy/core/scraper.py b/scrapy/core/scraper.py
index a85f6a661..a54929712 100644
--- a/scrapy/core/scraper.py
+++ b/scrapy/core/scraper.py
@@ -364,6 +364,7 @@ class Scraper:
                     spider=spider,
                     exception=output.value,
                 )
+            assert ex
             logkws = self.logformatter.item_error(item, ex, response, spider)
             logger.log(
                 *logformatter_adapter(logkws),
diff --git a/scrapy/logformatter.py b/scrapy/logformatter.py
index 600da0d40..9b05e1153 100644
--- a/scrapy/logformatter.py
+++ b/scrapy/logformatter.py
@@ -114,7 +114,7 @@ class LogFormatter:
         }
 
     def item_error(
-        self, item: Any, exception, response: Response, spider: Spider
+        self, item: Any, exception: BaseException, response: Response, spider: Spider
     ) -> dict:
         """Logs a message when an item causes an error while it is passing
         through the item pipeline.