gistfile1.txt

1.8と1.9でstack level too deepのでるタイミングも違う
>> RUBY_VERSION
=> "1.8.7"
>> class Fixnum
>> def add_one(o)
>> self + o + 1
>> end
>> end
=> nil
>> 1 + 1
=> 2
>> class Fixnum
>> def add_one(o)
>> self + o + 1
>> end
>> alias_method "+", "add_one"
>> end
=> Fixnum
>> 1 + 1
(irb):10:in `+': stack level too deep (SystemStackError)
	from (irb):10:in `+'


ruby-head > RUBY_VERSION
 => "1.9.3" 
ruby-head > class Fixnum
ruby-head ?>  def add_one(o)
ruby-head ?>    self + o + 1
ruby-head ?>    end
ruby-head ?>  alias_method "+", "add_one"
ruby-head ?>  end
 => Fixnum 
(irb):9: stack level too deep (SystemStackError)