C++ FE question: When is CLASSTYPE_VBASECLASSES valid?

[Doug Kwan (關振德)]

Hi,

    I have a question about the validity of CLASSTYPE_VBASECLASSES.
Due to templates, it is not possible to know if a class has virtual
bases or not until the class is fully instantiated.  Is checking
processing_template_decl sufficient to guarantee that
CLASSTYPE_VBASECLASSES is valid?

Thanks.

-Doug