React.PropTypes.shape({ ... }) missing description and required

If I have the following:

``` js
propTypes: {
  /**
   * a shapely shape
   */
  shape: React.PropTypes.shape({
    /**
     * a shapely property
     */
    subprop: React.PropTypes.number
  })
}
```

I get `description` and `required` fields on the `shape` property, but not on `subprop`.
