- メソッドを呼び出す為
user = User.new # 以下は同じ意味 user.name user::name
- 定数の呼び出し
class User ID = 123 end User::ID => 123
module Member class User def name end end end Member::User.name
参考
https://qiita.com/hatorijobs/items/87a2bd93f8666d77d711
https://knowledge-blog.net/articles/22