Re: Why is this ambiguous
James Kanze wrote:
loufoque wrote:
Eric B wrote :
Here is the scenario:
template <typename T>
class Base
{
protected:
Notify(T& msg);
};
struct msgA {};
struct msgB {};
class Impl : public Base<msgA>, public Base<msgB>
{
void Do()
{
msgA a;
Notify(a); // <----- AMBIGUOUS call
}
}
You should use virtual inheritance.
Where, how and why?
It's possible that he should use virtual inheritance somewhere.
Without seeing the rest of the hierarchy, especially classes
which derived from Impl, it's impossible to tell (and arguably,
unless you can be sure that it won't be needed later, e.g.
because Impl is logically a final class, and won't be derived
from, inheritance should be virtual by default). Virtual
inheritance is, however, irrelevant here, and would change
nothing.
What if Base was defined as:
class VBase {};
template <typename T>
class Base : public virtual VBase
{
protected:
Notify(T& msg);
};
would that allow the compiler to consider the bases as from the same
type?
Eric
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