#states doesn't work with #type 'date'

The following code doesn't work:

  $form['date'] = array(
    '#title' => 'Date',
    '#type' => 'select',
    '#options' => array(
      'day' => 'Day',
      'week' => 'Week',
      'custom' => 'Custom'
    ),
  );
  $form['date-custom'] = array(
    '#type' => 'date',
    '#title' => 'Custom date',
    '#states' => array(
      'visible' => array(
        'select[name="date"]' => array('value' => 'custom'),
      )
    ),
  );