Roadmap for improving the type checker In the past, we've released various "manifestos" and "roadmaps" to discuss planned improvements to the language. This post is also a roadmap of sorts, but instead, the focus is on the implementation rather than user-visible language changes (however, I will briefly mention a few potential language changes at the very end). Specifically, I'm going to talk about some work we are doing to improve expression type checking in the Swift compiler. This includes c...