Issue #3347291: Combine field storage and field instance forms

core/lib/Drupal/Core/Field/WidgetBase.php

@@ -173,7 +173,7 @@ protected function formMultipleElements(FieldItemListInterface $items, array &$f
         break;
 
       default:
-        $max = ((int) $cardinality) - 1;
+        $max = $cardinality - 1;
         break;
     }