main.rb:1: warning: irb used to be loaded from the standard library, but is not part of the default gems since Ruby 4.0.0.
You can add irb to your Gemfile or gemspec to fix this error.
Failed to activate irb, please install it with 'gem install irb'
/Users/osyoyu/.rbenv/versions/master/lib/ruby/4.0.0+0/bundled_gems.rb:60:in 'Kernel.require': cannot load such file -- irb (LoadError)
Did you mean?  erb
        from /Users/osyoyu/.rbenv/versions/master/lib/ruby/4.0.0+0/bundled_gems.rb:60:in 'block (2 levels) in Kernel#replace_require'
        from main.rb:1:in 'Binding#irb'
        from main.rb:1:in '<main>'
/Users/osyoyu/.rbenv/versions/master/lib/ruby/4.0.0+0/bundled_gems.rb:60:in 'Kernel.require': cannot load such file -- irb (LoadError)
Did you mean?  erb
        from /Users/osyoyu/.rbenv/versions/master/lib/ruby/4.0.0+0/bundled_gems.rb:60:in 'block (2 levels) in Kernel#replace_require'
        from main.rb:1:in 'Binding#irb'
        from main.rb:1:in '<main>'

$ cd fail
$ bundle exec ruby main.rb