Issue #1165 has been updated by ujihisa .. Current documentations don't mention about a subclass of Range. http://www.ruby-doc.org/core/classes/Range.html#M000690 http://doc.okkez.net/191/view/method/Range/i/=3d=3d Actually the Japanese one was fixed not to mention about a subclass of Range in May. http://redmine.ruby-lang.org/issues/show/1446 ---------------------------------------- http://redmine.ruby-lang.org/issues/show/1165 ---------------------------------------- http://redmine.ruby-lang.org