Automatic conversion to base class when calling constructor.

[Belebele]

I would like to have the compiler bind a Base class const reference to
a temporary object of a Derived class when calling another class
constructor. Please see the code below:

class Base {};

class Derived: public Base {};

class Foo {
public:
Foo(Base const& );

void bar();
};

int main()
{
Foo foo(Derived());

foo.bar();
}



One compiler gives me the following error:
error: expression must have class type foo.bar();

Another compiler also complains:
error: request for member `bar' in `foo', which is of non-aggregate
type `Foo ()(Derived (*)())'

Any idea why?

[Piyo]

Re: Automatic conversion to base class when calling constructor.

Belebele wrote:

I would like to have the compiler bind a Base class const reference to
a temporary object of a Derived class when calling another class
constructor. Please see the code below:
>
class Base {};
>
class Derived: public Base {};
>
class Foo {
public:
Foo(Base const& );
>
void bar();
};
>
int main()
{
Foo foo(Derived());
>
foo.bar();
}
>
>
>
One compiler gives me the following error:
error: expression must have class type foo.bar();
>
Another compiler also complains:
error: request for member `bar' in `foo', which is of non-aggregate
type `Foo ()(Derived (*)())'
>
Any idea why?
>

This is the reason why you see that error.

http://www.parashift.com/c++-faq-lite/ctors.html#faq-10.19

HTH