Base class constraint on generic class specifying the class itself

Question

Yesterday, I was explaining C#\'s generic constraints to my friends. When demonstrating the where T : CLASSNAME constraint, I whipped up something like this:

Answer 1

If any of these is possible, what would the type of T be?

They are all possible, and you are the one who is gonna determine what is the type of T.For example let's assume there is a type that inherits from UnusableClass

class Foo : UnusableClass { }

Now you can instantiate UnusableClass because Foo satisfies the constraint:

UnusableClass f = new UnusableClass();

Then the type of T become Foo and if you try to call method you need to pass an instance of Foo.