Generic List of Generic Interfaces not allowed, any alternative approaches?

Question

I am trying to find the right way to use a Generic List of Generic Interfaces as a variable.

Here is an example. It is probably not the best, but hopefully you will get

Answer 1

You say it won't work because you don't define T. So define it:

public class Holder
{
    public List> Primitives {get;set;}
}