Re: [boost] is_polymorphic and unions

From: Nicodemus (nicodemus_at_[hidden])
Date: 2003-03-18 21:42:43

David Abrahams wrote:

>Nicodemus <nicodemus_at_[hidden]> writes:
>
>  
>
>>>Is this happening somewhere in the type traits code?  Can you post an
>>>instantiation backtrace?
>>> 
>>>      
>>>
>>It seems to be. Here's the error message:
>>    
>>
>
>I guess the question here is: "should
>is_polymorphic<some_union>::value compile?"
>
>If so, then we have a bug in is_polymorphic.  If not, we should
>change all uses of is_polymorphic<T> in 
>
>       boost/python/class.hpp
>       boost/python/object/class_converters.hpp
>       boost/python/object/inheritance.hpp
>
>to:
>         mpl::and_<is_class<T>, is_polymorphic<T> >
>
>You can make this patch yourself in Boost.Python as an interim
>measure to see if it makes wrapping unions work.
>  
>

I did it, but it didn't work. is_class<some_union>::value evaluates to 
true. 8/

I believe that is_polymorphic<some_union>::value should evaluate to 
false, since unions can't be polymorphic.