Plain old covariance and contravariance

[BCS]

Jari-Matti Mäkelä wrote:
> BCS wrote:
> 
>>
>>
>>This would also allow a single class to implement several (3rd party)
>>interface that have methods with the same signature but different
>>semantics.
[...]
> 
> 
> It's better to use naming conventions to avoid these kind of semantic
> collisions.

Yes that is the first solution, but some times that isn't an option, 
consider using 3rd party, closed source libs.