What is the name of this pattern (interface inheritance)?

Question

We recently had an issue in C# when working with DI containers and I wanted a clean solution, but I didn't find any resources for my approach.

We are using DryIoc heavily and whenever we need a collection of items, there is a Repository or Registry or whatever to keep the items in one place.

This approach has some downsides:

• A developer has to know where he has to register it's class.

• The registry and its purpose have to be documented

• Some objects have to be resolved by another object (Object A relies on Object B) as a feature, so almost duplicate registries or repositories and even more dependencies.

My approach is to create generic interfaces like this:

interface IBeverage { }

interface IBeverage<out T> : IBeverage where T : IBeverage{ }

This is quite equal to CRTP, but slightly different as I have a base interface and work solely with Interfaces. The advantage is that I have a strong hierarchy, but can use this to express Features or Meta Information without inheritance:

interface ICaffeine { }

interface ICaffeine<out T> : ICaffeine where T : ICaffeine{ }

Both a coffee and an energy drink are implementing both interfaces, while water only implements the first one:

class Coffee : IBeverage<Coffee>, ICaffeine<Coffee> { }

class EnergyDrink : IBeverage<EnergyDrink>, ICaffeine<EnergyDrink> { }

class Water : IBeverage<Water> { }

class CaffeineTablet : ICaffeine<CaffeineTablet> { }

When I now want to resolve all beverages, I can resolve with

container.Resolve<IEnumerable<IBeverage>>();

Or all caffeine:

container.Resolve<IEnumerable<ICaffeine>>();

Now, I've changed the Interfaces a little bit more to:

interface IBeverage { }

interface IBeverage<out T> : IBeverage { }

interface ICaffeine { }

interface ICaffeine<out T> : ICaffeine { }

Because both interfaces are simply features and can now request them from DryIoc like this:

//Returns coffee, energy drink, and water

var allBeverages = container.Resolve<IEnumerable<IBeverage>>();

//Returns coffee, energy drink, and caffeine tablet

var allCaffeine = container.Resolve<IEnumerable<ICaffeine>>();

//Returns coffee and energy drink

var allBeveragesWithCaffeine = container.Resolve<IEnumerable<IBeverage<ICaffeine>>>();

I could even add a third feature or add a feature like HotBeverage : Beverage and it still works like a charm.

I was stunned after I found out about this feature, but how is my pattern called? I really would like to find more information about it.