shouldn't override be obligatory?

[Jonathan M Davis]

div0 wrote:

> Strangely it doesn't give an error if A is an interface though.

Interfaces aren't overridden; they're implemented. You're providing 
functionality, not replacing it. By marking a function with override, you're 
clearly marking that it's polymorphic and intended to be so. If you force 
override for all cases when a function is overridden, then you avoid issues 
where you unknowingly override a function, changing the objects behavior. 
That's not a problem with interfaces since there's no behavior to change. 
The problem with interfaces is when you don't implement them completely, and 
they complain plenty when that happens.

- Jonathan M Davis