It's not quite that simple, OP is right, pace on Swift improvement slowed to a crawl for 3? years now as they played whack-a-mole with type inference and got to stable ABI. It was only supposed to take a year, and, it's utterly __shocking__ to find out the type inference whack-a-mole intractable _after_ pushing the stable ABI.

Working at FAANG is an abject lesson in learning that assuming 'competence' (i.e. knowing mastery-level detail, taking responsibility everywhere, and going off on world-creating tangents rather than fixing bugs) is damn rare, nearly all of my career's achievements have come of accepting that and doing deep dives into problems.

The issue OP mentioned is certainly not intractable to fix, and in general type inference doesn't have much to do with the stable ABI. The ABI work was about refactoring some compiler internals and implementing library evolution support, which as far as I'm aware is unique among statically-compiled languages: https://swift.org/blog/library-evolution/. There was also a lot of work on code size improvements, runtime memory usage, and compilation time. The pace at which language features are added is not the only valid measure of language development.

Those are all arguments your team has been repeating for a while, and I used to be amenable to, but am no longer given the amount of time that has elapsed.

Something is pretty broken over there, and it's especially not charming to read the team chiming in with 'lol haskell too!' - can I bill you for the type inference crashes and workarounds I've had to do because no one bothered saying anything until August 2020? https://twitter.com/krzyzanowskim/status/1305579668104331264...

I'll be happy to admit I'm wrong when Swift UI 2021 is rendering lazy lists just fine on Mac and iOS, otherwise, its just me hearing about ARC optimizations for the 50th time and trusting it. https://twitter.com/jckarter/status/1305562770859933696?s=20

> can I bill you for the type inference crashes and workarounds I've had to do because no one bothered saying anything until August 2020?

That's not related to the decidability of that specific algorithm in the generics implementation, though.

Did you file bugs for the type checker problems you found? (I’m not being snarky; I’d love to take a look at them)

> it's actually rather hard to ensure decidability

How is it that a single person named Edwin Brady can think of, implement and have a programming language with a decidable type system that is more complex than Swift, working on it part-time?

I'm sorry, I consider a company worth a trillion dollars, sitting on billions of dollars it doesn't know what to spend on, that spends billions per year on R&D, to know the basic properties of the type system their most actively developed programming language uses.

That's just me.

By focusing entirely on the type system rather than building a programming language usable for actually building applications. Idris is a wonderful research language, but is awful as a language to write production software in.