Nondescript Error in Interface

I have a weird bug in an Interface.

It is not the name Index, it is red with any other name too.
Hovering over the method name does not give any clue on what’s wrong.

I see the bug in gamma 2020.1.3 and beta40.
bug.vl (3.5 KB)

edit: Is maybe Create a reserved name, that cannot be used in an interface?

Yes, Create is the constructor and is not allowed in interfaces since you cannot create interface types directly, you can only create concrete types that implement an interface. Here is more about that:

Yes, I am aware that one cannot instanciate an interface in c#.

But since we are talking about Records here, and common method signatures, maybe it should be allowed in vl?
I mean, it is fully ok to have a Join in the interface, but having a Create fails hard without a proper error message. That is not ok.

Hi Velcrome, for an interface I’ve been making lately the constructor for those types is always different, though there are common parameters. If the constructor is going to be the same for all of your objects, maybe what would be handy is a template for them. The objects themselves could still inherit the Interface for later