Covariance and Contravariance FAQ

In this post I’ll try to answer the most common questions I find on forums and in documentation feedback about C# covariance and contravariance. It’s a big topic for a single blog post, so expect to see a lot of “more information” links. Special thanks to Eric Lippert and Chris Burrows for reviewing and providing helpful comments.What are covariance and contravariance?In C#, covariance and