RuboCop Rubycw

Integrate RuboCop and ruby -cw.

You can get Ruby's warning as a RuboCop offense by rubocop-rubycw.


  • Ruby 2.4 or greater.
    • But I highly recommend to use Ruby 2.6 or greater. Because it is about 10x slower if it works on Ruby 2.5 or lower.


Add this line to your application's Gemfile:

gem 'rubocop-rubycw', require: false

And then execute:

$ bundle install

Or install it yourself as:

$ gem install rubocop-rubycw


Put this into your .rubocop.yml.

require: rubocop-rubycw


After checking out the repo, run bin/setup to install dependencies. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to


Bug reports and pull requests are welcome on GitHub at