Async-await is due to hit stable in the 1.39 release (only a month away!), and as announced in the ["Async Foundations Update: Time for polish!"][previous_post] post last month, the Async Foundations WG has shifted its focus to polish. This post will highlight one aspect of that focus, diagnostic improvements, and in particular, the improvements that the working group has been making to the once-unhelpful "future is not send" diagnostic. # Why doesn't my future implement `Send`? One of the maj