1 files changed, 11 insertions, 3 deletions
diff --git a/actionpack/lib/action_dispatch/http/mime_type.rb b/actionpack/lib/action_dispatch/http/mime_type.rb
index 912da741b7..f29ad359ac 100644
--- a/actionpack/lib/action_dispatch/http/mime_type.rb
+++ b/actionpack/lib/action_dispatch/http/mime_type.rb
@@ -223,8 +223,8 @@ module Mime
         Mime.instance_eval { remove_const(symbol) }
 
         SET.delete_if { |v| v.eql?(mime) }
-        LOOKUP.delete_if { |k,v| v.eql?(mime) }
-        EXTENSION_LOOKUP.delete_if { |k,v| v.eql?(mime) }
+        LOOKUP.delete_if { |_,v| v.eql?(mime) }
+        EXTENSION_LOOKUP.delete_if { |_,v| v.eql?(mime) }
       end
     end
 
@@ -306,12 +306,20 @@ module Mime
       method.to_s.ends_with? '?'
     end
   end
-  
+
   class NullType
     def nil?
       true
     end
 
+    def ref
+      nil
+    end
+
+    def respond_to_missing?(method, include_private = false)
+      method.to_s.ends_with? '?'
+    end
+
     private
     def method_missing(method, *args)
       false if method.to_s.ends_with? '?'