You're correct in your assumption you'd need to generate methods, from my quick investigation into how Sorbet handles it - see https://github.com/chanzuckerberg

You're correct in your assumption you'd need to generate methods, from my quick investigation into how Sorbet handles it - see https://github.com/chanzuckerberg/sorbet-rails https://github.com/chanzuckerberg/sorbet-rails for some details.