For simple predicates, expound reports "unknown" spec

[bhb]

(expound/expound string? 1)

Actual:

-- Spec failed --------------------

  1

should satisfy

  unknown

Expected:

-- Spec failed --------------------

  1

should satisfy

  string?

We are looking just for the predicate, which is unknown in this case. We should look at the :clojure.spec.alpha/spec key (top-level)