gistfile1.rbx

class Foo
  def initialize &block
    p instance_eval &block if block_given? # !> `&' interpreted as argument prefix
  end
  def const_missing const
    "foobar"
  end
end

Foo.new {self} # => #<Foo:0x27204>
# should be
(class << Foo.new; self; end) # => #<Class:#<Foo:0x27038>>