From: Jay Date: 2010-11-02T23:36:47+09:00 Subject: [ruby-core:33010] OpenStruct.delete_field() It seems: def delete_field(name) @table.delete name.to_sym end should be: def delete_field(name) @table.delete name.to_sym begin class << self; self; end.class_eval do remove_method(name.to_sym) end rescue end end in ostruct.rb line 103 1.9.1