C# generic “where constraint” with “any generic type” definition?

Question

Let me give example:

1. I have some generic class/interface definition:

   interface IGenericCar< T > {...}

2. I have another class/interface that I want to relate with class above, for example:

   interface IGarrage< TCar > : where TCar: IGenericCar< (**any type here**) > {...}

Basically, I want my generic IGarrage to be dependent on IGenericCar, regardless if it's IGenericCar<int> or IGenericCar<System.Color>, because I don't have any dependency to that type.

Answer 1

There are typically 2 ways to achieve this.

Option1: Add another parameter to IGarrage representing the T which should be passed into the IGenericCar<T> constraint:

interface IGarrage<TCar,TOther> where TCar : IGenericCar<TOther> { ... }

Option2: Define a base interface for IGenericCar<T> which is not generic and constrain against that interface

interface IGenericCar { ... }
interface IGenericCar<T> : IGenericCar { ... }
interface IGarrage<TCar> where TCar : IGenericCar { ... }

Answer 2

Would it make any sense to do something like:

interface IGenericCar< T > {...}
interface IGarrage< TCar, TCarType > 
    where TCar: IGenericCar< TCarType > {...}