1 files changed, 4 insertions, 0 deletions
diff --git a/actionpack/lib/action_dispatch/http/mime_type.rb b/actionpack/lib/action_dispatch/http/mime_type.rb
index c24c9a1bc3..f29ad359ac 100644
--- a/actionpack/lib/action_dispatch/http/mime_type.rb
+++ b/actionpack/lib/action_dispatch/http/mime_type.rb
@@ -312,6 +312,10 @@ module Mime
       true
     end
 
+    def ref
+      nil
+    end
+
     def respond_to_missing?(method, include_private = false)
       method.to_s.ends_with? '?'
     end