What is a “circular argument reference” error, wit

问题:

I'm new in ruby on rails, and I am trying to create a tutorial. I have a problem when I execute rake db:migrate.

hugo@ubuntu:~/pin_board$ rake db:migrate
/home/hugo/.rvm/gems/ruby-2.2.2/gems/activesupport-4.0.5/lib/active_support/values/time_zone.rb:283: warning: circular argument reference - now

What causes this?
Can somebody help me?

回答1:

You see this warning message because your Rails version is 4.0.5. The issue has been fixed on Rails 4.0.6.

Update your Gemfile and run bundle update rails.

If you want to know the background of this issue, read my answer to another question https://stackoverflow.com/a/30733016/513554.