API Resource: example and description are lost if union type has more than 2 members

[petert82]

Using v0.12.11, when trying to document an API resource like this:

/**
 * @mixin MyModel
 */
class MyModelResource extends JsonResource
{
    public function toArray(Request $request): array
    {
        return [
            /**
             * The first field
             * @var string|null
             * @example "Some example value"
             */
            'field_one' => $this->field_one,
            /**
             * The second field
             * @var string|null|boolean
             * @example "Some other example"
             */
            'field_two' => $this->field_two,
        ];
    }
}

The generated documentation for field_one works as expected, and includes the description from the doc block as well as the given example:

{
  "type": [
    "string",
    "null"
  ],
  "description": "The first field",
  "examples": [
    "Some example value"
  ]
}

However field_two ignores the description and the example, and just documents that it can be any of string, null or boolean:

{
  "anyOf": [
    {
      "type": "string"
    },
    {
      "type": "null"
    },
    {
      "type": "boolean"
    }
  ]
}

I'm not sure if I'm missing a way to annotate the field to make this work they way I would expect for field_two, or if this is a bug?