Re: Visual C++ bug report

Hi Bruno,

> global scope is not required. they just have to be in the same namespace.
> if you put them in namepace bla it has the same result.

I didn't say "global scope", I said "namespace scope"... :-)

> that being said, i don't know if the behavior in this case is defined or 
> not.
> the safest thing to do is to provide tag names.

The C++ Standard is pretty clear in explaining what you should expect from 
the typeid operator, and unnamed classes are not mentioned as a particular 
condition to be aware of. The paragraph that can be applied to my example is 
the following:

"When typeid is applied to an expression other than an lvalue of a
polymorphic class type, the result refers to a type_info object representing
the static type of the expression. "

Unless I'm not misinterpreting that, the Standard states that typeid(A) 
returns a type_info representing the static type of A, and typeid(B) returns 
a type_info representing the static type of B. In my example the static type 
of A is clearly different from that of B, but the two type_info objects 
result to be equal (or at least indistinguishible one from the other), and 
that's a violation of the above statement.

As for using tag names I agree with you, but I'm writing a 
reflection/introspection framework, so being unable to distinguish between 
two different types is a heavy deficiency for my project. I personally avoid 
using unnamed classes, but the library I'm writing must exhibit consistent 
behavior when used with foreign code I have no control on. :-/

Cheers,
Marco


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