Get only direct interface instead of all?

Question

I have a class like the below. GetInterfaces() says

If the current Type represents a type parameter in the definition of a generic type or generic

Answer 1

As far as I can tell, none of the posted solutions work for typeof(C1) and typeof(I3) in the example below.

I think the correct answer is that it is not possible to get the directly implemented interfaces using out-of-the-box framework calls.

private interface I1 { }

private interface I2 : I1 { }

private interface I3 : I2, I1 { }

public class C1 : I3, I1 { }