Why shouldn't C#(or .NET) allow us to put a static/shared method inside an interface?

Question

Why shouldn\'t C#(or .NET) allow us to put a static/shared method inside an interface?

seemingly duplicate from here. but my idea is a bit different one, I just wan

Answer 1

The idea of an interface is to represent a contract, not implementation.

I can't remember offhand whether IL actually does allow static methods with implementations in interfaces - I've a sneaky suspicion that it does - but that muddies the concept somewhat.

I can see your point - it's sometimes useful to know what helper methods are available which are connected with an interface (and extension methods are particularly relevant there) but I would personally want to put those in a separate class anyway, just to keep the mental model clean.