Just learnt about dependent function types in Scala 3. This is what I want most of the core annotations to look like, so functions can work with both simple and complex (heterogenous) types without needing extra annotations https://docs.scala-lang.org/scala3/book/types-dependent-function.html This is the type I want to give clojure.core/seq:

(t/All [[x :< (t/Seqable t/Any)]]
       [x :-> (t/SeqOn x) :object {:id 0 :path [Seq]}])