Broken contract programing

[via Digitalmars-d]

On Wednesday, 13 May 2015 at 23:49:51 UTC, Idan Arye wrote:
> That a type system can solve this problem if it supports 
> covariant and contravariant generic/template parameters.

Not if someone else provided the super class, and generics simply 
bypasses the OO-inheritance model. Anyway, the key point was that 
uses of type systems that are workable (not overly tedious) can 
only catch the most obvious bugs at compile time. Therefore it is 
useful to be able to constrain invariants to a point where they 
ensure correctness, not type-soundness.