Empty HQL query throws exception

On the Query Module documentation page the first example you see is:

Query Description	XWQL	HQL
Query listing all documents	<empty query>	<empty query>

It doesn't work! Try this:

{{velocity}}
$services.query.hql('').setLimit(10).execute()
{{/velocity}}

You'll get:

Caused by: org.hibernate.hql.ast.QuerySyntaxException: unexpected end of subtree []

The XWQL empty query works.