A big +1. This is an excellent proposal. I appreciate its technical care. I appreciate its attention to language ergonomics. I appreciate its motivating examples and thoughtfully stated rationale. And I especially appreciate how carefully it translates that rationale into recommendations about ongoing best practice. Some SE proposals are “Let’s see what people do with it!” proposals. Not this one. Swift developer norms — culture and habit — are going to be a crucial part of making this new feat...