I see what you mean, but uninstantiated also means unused. So we're not talking about anything that could possibly lead to runtime errors. It's not an issue wit

I see what you mean, but uninstantiated also means unused. So we're not talking about anything that could possibly lead to runtime errors. It's not an issue with type safety. It definitely has a downside for the development process, especially when it comes to writing libraries. But it is also to some degree inevitable if you want structural typing. Maybe there is a better way to do it though.