Ticket #16347: 16347.2.diff

wp-includes/query.php

@@ -2966 +2966 @@
                 if ( empty( $post_types ) || !$this->is_post_type_archive )
                         return (bool) $this->is_post_type_archive;
 
-                if ( ! isset( $this->posts[0] ) )
-                        return false;
+                $post_type_object = $this->get_queried_object();
 
-                $post = $this->posts[0];
-
-                return in_array( $post->post_type, (array) $post_types );
+                return in_array( $post_type_object->name, (array) $post_types );
         }
 
         /**