polymorphism: overloading vs. overriding

[Mike Parker]

Bruno Medeiros wrote:
> Mike Parker wrote:
>>
>> This line is the key:
>>
>> Foo foo = new Bar();
>>
>> foo is an instance of Foo, not an instance of Bar, 
> 
> No, that is wrong, foo *is* an instance of Bar. (yet, it's type contract 
> is only that it is a Foo)
> 

Yes, yes. Underneath the foo is an instance of Bar. But because, as you 
say, the type contract is that of Foo then you are effectively dealing 
with a Foo and not a Bar. It should only be treated as a Bar when you 
downcast.