A case where the `:in` value is not a path to the value

map_of_ex.cljs

;;[org.clojure/clojure "1.9.0-alpha17"]
;;[org.clojure/clojurescript "1.9.542"]
;;[org.clojure/spec.alpha "0.1.123"]

(s/def :foo.user/name string?)
(s/def :foo/user (s/keys :req-un [:foo.user/name]))
(s/def :foo/user-map (s/map-of :foo.user/name :foo/user))
(s/explain-data :foo/user-map {"bob" {:age 2 :city "chicago"}})
;; returns the following...
(comment
  #:cljs.spec.alpha{:problems
                    ({:path [1],
                      :pred (contains? % :name),
                      :val {:age 2 :city "chicago"},
                      :via [:foo/user-map :foo/user], 
                      :in ["bob" 1]})})

;; I would (perhaps mistakenly?) expect the `:in` value to be just ["bob"] since
;; (get-in {"bob" {:age 2 :city "chicago"}} ["bob"]) is {:age 2 :city "chicago"}