Then you find real golang code littered with things like var _ Animal = (*Cat)(nil) var _ Animal = (*Dog)(nil) and you're back to the same place with

Then you find real golang code littered with things like var _ Animal = (*Cat)(nil) var _ Animal = (*Dog)(nil) and you're back to the same place with more verbosity, and with much more difficulty when trying to figure out which types implement which interfaces. Much more load on IDEs as well.