CriteriaBuilder doesn't work with ELEMENT_COLLECTION

[Oribow]

I have a domain object with a collection of non-domain objects.

class Person{
    static hasMany = [knownContacts: KnownContacts]
}

enum KnownContacts{
    None,
    Email,
    Phone
}

I want to use this "association" in a criteria, but that throws a groovy.lang.MissingMethodException: No signature of method error at knownContacts { ... }.

{
    projections {
        knownContacts {
            id()
        }
    }
}

This is because gorm treats the "knownContacts" not as an association, but as an ELEMENT_COLLECTION.
Which means the isAssociation check fails on it, as its PersistentAttributeType is ELEMENT_COLLECTION.

public boolean isAssociation() {
		return getPersistentAttributeType() == PersistentAttributeType.ONE_TO_MANY
				|| getPersistentAttributeType() == PersistentAttributeType.MANY_TO_MANY;
	}

There doesn't seem to be any code in AbstractHibernateCriteriaBuilder.invokeMethod that deals with ELEMENT_COLLECTIONs.

          if (pd != null && pd.getReadMethod() != null) {
                final Metamodel metamodel = sessionFactory.getMetamodel();
                final EntityType<?> entityType = metamodel.entity(targetClass);
                final Attribute<?, ?> attribute = entityType.getAttribute(name);

                if (attribute.isAssociation())
                   [...]

The attribute.isAssociation check fails and the throw new MissingMethodException(name, getClass(), args); at the end of the method is reached.

I'm not sure if this is intentional or an oversight. Is there a different way we are supposed to query non domain to domain associations?

The generated database schema creates an extra table for ELEMENT_COLLECTION (at least in this case) so I'm not sure why they can't be used like regular associations between domain objects.