> It's easy to understate how big of a deal this is for the compiler. This work resolves a major piece of technical debt that a lot of compiler developers dreamed about for years.
No kidding. I’ve been waiting for the solver at least half that decade now. Hopefully it and Polonius unblock specialization which has been in purgatory for years.
There's some movement on specialization as well: https://goals.rust-lang.org/2026/specialization.html
It's not directly blocked on the solver, but getting the type system into a better shape definitely helps reasoning about the soundness issues involved.
More precisely: it wasn't known to be blocked on the new solver (unlike some other features), because nobody dared to touch it until recently... (more seriously, there wasn't enough investment).