Problem understanding covariance contravariance with generics in C#

Question

I can\'t understand why the following C# code doesn\'t compile.

As you can see, I have a static generic method Something with an IEnumerable parame

Answer 1

I just wanted to complement Eric's excellent insider answer with a code example for those that may not be that familiar with generic constraints.

Change Something's signature like this: The class constraint has to come first.

public static IList Something(IEnumerable foo) where T : class, IA