Issue #9155 has been updated by hsbt (Hiroshi SHIBATA). Assignee set to nobu (Nobuyoshi Nakada) Priority changed from Normal to High It happened will_paginate too. follow code. https://github.com/mislav/will_paginate/blob/master/lib/will_paginate/page_number.rb ---------------------------------------- Bug #9155: DelegateClass - ArgumentError: not delegated https://bugs.ruby-lang.org/issues/9155#change-43145 Author: rhs (Russell Smith) Status: Open Priority: High Assignee: nobu (Nobuyoshi Nakada) Category: Target version: current: 2.1.0 ruby -v: ruby 2.1.0dev (2013-11-23 trunk 43807) [x86_64-darwin13.0] Backport: 1.9.3: UNKNOWN, 2.0.0: UNKNOWN Running the attached code gives ArgumentError: not delegated. It's unexpected as it worked on preview 1 and in 2.0.0. Error pasted below. https://gist.github.com/ukd1/9293c419a080d034f4bb - has sample code plus runs on 2.0.0p247 + 2.1.0-preview1 and 2.1.0-preview2 ArgumentError: not delegated from /Users/russ/.rvm/rubies/ruby-2.1.0-preview2/lib/ruby/2.1.0/delegate.rb:384:in `__getobj__' from /Users/russ/.rvm/rubies/ruby-2.1.0-preview2/lib/ruby/2.1.0/delegate.rb:77:in `method_missing' from (irb):5:in `initialize' from (irb):11:in `new' from (irb):11 from /Users/russ/.rvm/rubies/ruby-2.1.0-preview2/bin/irb:11:in `<main>' -- http://bugs.ruby-lang.org/