As someone using Swift’s concurrency features on a daily basis, I don’t understand what “deep concurrency” is and what Swift 6 is supposed to change except for enforcing Sendable conformance for every symbol shared across concurrency contexts. The tools have all been there for a while.
I think the initial idea of concurrency safeguards at build time have grown a bit out of proportion. It's so much more than "sendable" conformance that my head is starting to spin just thinking about it. There is also the "sending" label for reference types (in addition to Actors, Tasks, Executors, isolation regions, context, preconcurrency...). It's becoming impractical. I don't think developers really asked for any of this.
