const and class

const_test.rb

class Foo
  attr_accessor :me

  def initialize(arg)
    @me = arg
  end
end

class Bar
  def execute
    foo = Foo.new('bar class!')
    puts foo.me
  end
end

class Baz
  Foo = 'missing!!'

  def execute
    foo = Foo.new('baz class!')
    puts foo.me
  end
end

bar = Bar.new
bar.execute
# => "bar class!"

baz = Baz.new
baz.execute
# => undefined method `new' for "missing!!":String (NoMethodError)
# Fooクラスが"missing!!"文字列に置き換えられてしまった