Q: Should static interface members without implementation be allowed?

[ScottKane]

Doing this could then force opt in static implementation enforcement so that the derived class must implement the static member as static.

interface IA
{
    static void M();
}
class Derived: IA
{
    public static void M() { }
}

[DaZombieKiller]

You're looking for #164.

[333fred]

I would say it's a duplicate of #110 (type classes), not necessarily shapes. We also discussed this in LDM a couple months ago: https://github.com/dotnet/csharplang/blob/master/meetings/2020/LDM-2020-06-29.md. Closing this out, please redirect discussion to one of the linked places :).