On Friday, 27 June 2014 at 21:23:52 UTC, Mark Isaacson wrote:
If I have a variable whose static type is an interface and I
call
typeid on it, I get the interface back, not the dynamic type.
This seems like confusing behavior. Is this the intended result?
I recognize that one needs some amount of state to perform the
dynamic type lookup, and so it is on that thought that a reason
for this might be based.
Interfaces are not necessarily Objects (particularly with the
case of IUnkown or extern(C++)), and are handled somewhat
differently from objects.
When you cast to Object, you're actually subtracting a few bytes
from the pointer to get back to the Object, so technically the
variable refers not to Object but to the interface. It is a bit
odd (along with some of the other side-effects), but it does make
some sense since you're referring to the interface and not to an
Object.
That being said, I'm not 100% sure whether this is the intended
behaviour when you actually do point to a class derived from
Object.
