Which is why I prefer only being able to opt-in to late-binding where it makes sense: implementations that are late-bound in have to at least satisfy the type c

Which is why I prefer only being able to opt-in to late-binding where it makes sense: implementations that are late-bound in have to at least satisfy the type checker. Also, depending on environment, some sort of metadata may indicate to future readers/maintainers that late-binding is happening.