assert prop.getTypeCode( ) == PropertyType.ELEMENT_REF_TYPE;
assert prop.getTypeCode( ) == IPropertyType.ELEMENT_REF_TYPE;
	public ElementRefValue resolveElementReference( Module module,			ElementPropertyDefn prop )	{		Object value = propValues.get( prop.getName( ) );		assert value == null || value instanceof ElementRefValue;		assert prop.getTypeCode( ) == PropertyType.ELEMENT_REF_TYPE;		return resolveElementReference( module, prop, (ElementRefValue) value );	}