(collection-tag x)
user=> (clojure.inspector/collection-tag (first {:a 1 :b 2}))
;;=> :entry
user=> (clojure.inspector/collection-tag {:a 1})
;;=> :seqable
user=> (clojure.inspector/collection-tag #{:a 1})
;;=> :seqable
user=> (clojure.inspector/collection-tag [1 2])
;;=> :seq
user=> (clojure.inspector/collection-tag :a)
;;=> :atom