We believe that the main goal of a typechecker is to give you nice error messages. We've found giving names to things makes it easier for folks to reason about their errors, and introducing names for interfaces isn't that onerous at Stripe or with our beta testers.
We aren't opposed to eventually support it, but we'd like to see how it goes with the current form first.
We aren't opposed to eventually support it, but we'd like to see how it goes with the current form first.