class RSpec::Mocks::Space

def id_for(object)
  id = object.__id__
  return id if object.equal?(::ObjectSpace._id2ref(id))
  # this suggests that object.__id__ is proxying through to some wrapped object
  object.instance_exec do
    @__id_for_rspec_mocks_space ||= ::SecureRandom.uuid
  end
end