Rails nested classes autoload issue

I've created new simple Rails 6 application for test reasons.

In config/environments/development.rb

...
config.cache_classes = false
config.eager_load = false
...

/app/controllers/articles_controller.rb

class ArticlesController < ApplicationController
  def index
    Foo.test_foo
  end
end

/app/models/foo.rb

module Foo
  class << self
    def test_foo
      Bar.test_bar
    end
  end
end

/app/models/foo/bar.rb

module Foo
  class Bar
    class << self
      def test_bar
        puts "111"
      end
    end
  end
end

After calling articles controller i get error

NameError (uninitialized constant Bar):

app/models/foo.rb:4:in `test_foo'
app/controllers/articles_controller.rb:3:in `index'

When i enable eager loading(config.eager_load = true) - all become ok.

Second solve - using full namespace path Foo::Bar in /app/models/foo.rb like a

module Foo
  class << self
    def test_foo
      Foo::Bar.test_bar
    end
  end
end

And, ofcourse, i can use direct "require", but don't want it.

Is there way to use shorthands for nested classes without eager load and without using "require"?