Roadmap for Improving the Type Checker
Every time I tinker with languages like Rust or Crystal or Swift, I am amazed by their compilation times. OCaml and Pascal got this right aeons ago. I’m looking forward to a public release of Jai simply because compilation speed is one of its primary motivations. Having a fast feedback loop is crucial to my adhd-like development workflow.
I love the clean syntax of Swift, which allows you to omit a lot of syntactic noise. It's so much nicer to write and read than for example Rust with it's ugly wordiness. But the type checker performance really is inacceptable.
As someone who started doing SwiftUI recently, it absolutely boggles my mind that (1) this is even a thing and (2) Apple seem ok to treat it as an unsolvable problem. When you finally solve it is some stupid wrong type passed in somewhere. I agree with the other poster. This is so pathetic it makes me question the competence of the engineers working on Swift.
Smells like “we made a poor architectural / design choice and ain’t walking it back”.
Slava mentions both bidirectional inferencing and overloading as two of the big culprits.
I've been doing some language work recently, and I'm quite sympathetic to bidirectional inferencing. I think, though, that modern PLs need better solutions for adhoc overloading. It's notorious for its complexity, blowing up algorithmically, and confusing users with surprising results (why oh why did the compiler select this function over the one I intended). That said, I haven't discovered a good alternative (for my purposes) yet.
About time! Nothing kills productivity like waiting 30s for the compiler to tell you it can't infer a type on line 27437 (who needs to refactor?). The diagnostic improvements alone will be worth it really but...
Wow that `let url` example taking 10 seconds and only down to 6 seconds now is shockingly bad. As someone who recently started getting into iOS/macOS development and has noticed these wildly slow type checking times on my M2 Air, this is enough to make me reconsider if I want to invest in this platform...