Totally, the point I was making was only that, for a type system, you have to validate the keys in order to “type” the map. If you don’t validate the keys the type system can’t guarantee they’re there, so you’re back to square one.
With that said, another case occurred to me: partial validation. If you wanted to guarantee that a struct has, say, %{"id" => String.t} but allow any other fields, mixing atom keys and string keys would be pretty gross. I think that’s a pretty good argument for string literal types, actually. Consider making a thread about it!
