[bjr-]

I believe that's where core.typed is going: http://frenchy64.github.io/2015/06/19/gradual-typing.html

Typed and untyped code must (and will soon) be able to cooperate in providing compile-time and run-time type checking in Clojure.

[mattrepl]

There are also tentative plans to integrate core.typed with the Clojure compiler so type annotations can be used during compilation (e.g., type hints through inference).

There was a post about it, but the best I could find is a recent paper: http://frenchy64.github.io/papers/typed-clojure-draft.pdf