An example of map-of and `in`

map_of.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-map (s/map-of string? int?))
(s/explain-data :foo/user-map {"hi" "foo"})
;; Actual value:
;; #:cljs.spec.alpha{:problems
;;                 ({:path [1],
;;                   :pred int?,
;;                   :val "foo", 
;;                   :via [:foo/user-map], 
;;                   :in ["hi" 1]})}
;; Expected: the `:in` value to be ["hi"] ? 
(s/explain-data :foo/user-map {:hi 2})
;; Actual value: 
;; #:cljs.spec.alpha{:problems
;;                 ({:path [0],
;;                   :pred string?,
;;                   :val :hi, 
;;                   :via [:foo/user-map], 
;;                   :in [:hi 0]})}
;; Expected: I'm not sure. I can see the trouble with identifying the key itself.
;; Perhaps `[:hi 0]` indicates something like "find the key-value pair for :hi, then
;; get the 0th element of that key-value pair (i.e. the key)" ???