Remove duplicated to_s method call.

actionpack/lib/abstract_controller/base.rb

@@ -255,7 +255,7 @@ module AbstractController
 
       # Checks if the action name is valid and returns false otherwise.
       def _valid_action_name?(action_name)
-        action_name.to_s !~ Regexp.new(File::SEPARATOR)
+        action_name !~ Regexp.new(File::SEPARATOR)
       end
   end
 end

actionpack/lib/action_controller/metal.rb

@@ -226,7 +226,7 @@ module ActionController
 
     # Returns a Rack endpoint for the given action name.
     def self.action(name, klass = ActionDispatch::Request)
-      middleware_stack.build(name.to_s) do |env|
+      middleware_stack.build(name) do |env|
         new.dispatch(name, klass.new(env))
       end
     end