On 08/13/2015 06:05 PM, Steven Schveighoffer wrote:
On 8/13/15 11:59 AM, Steven Schveighoffer wrote:
That is definitely a bug. It's because typeid is looking up the derived
type via the vtable, but the compiler should rewrap it with 'shared'
afterwards.
Actually, now that I think about it, I'm not sure how the compiler can
figure this out.
There would have to be a way to construct a TypeInfo_Shared at runtime,
which the compiler shouldn't be doing. Alternatively, it could
proactively create a TypeInfo_Shared (and all the other flavors) for
each class type in the runtime, and then look it up using some hash
mechanism.
...
Can't the shared typeinfo be constructed for all superclasses of C at
the point where shared(C) is used? (Think: template instantiation.)
This likely isn't fixable.
...
I don't understand. It is evidently fixable. E.g. if TypeInfo was just a
template without the mostly redundant additional compiler support, this
would be a trivial fix.
