How does D improve design practices over C++?

[bearophile]

Janderson:
> D contracts take this one step futher then C++.  They allow one to 
> decouple the contracts from the code itself:

I think D contracts have to be improved to become really useful. I have used them very little so far in D because of that. At the moment the only contracts I see useful in D are the class invariants.
The good thing of contracts is that the compiler can use them to infer several useful things. You can look at Eiffel to see how much more useful they can become. If you want we can discuss a little about this topic, that seems too much ignored in the last discussion that pass in this newsgroup.

Bye,
bearophile