string vs number tempids pairity in pull api

[Dustin Getz]

Is this a bug? I can't pull a string tempid, but I can pull a num tempid.

(d/pull (d/db root-dbconn) ['*] -1)
=> #:db{:id -1}

(d/pull (d/db root-dbconn) ['*] "a")
IllegalArgumentExceptionInfo :db.error/not-a-keyword Cannot interpret as a
keyword: a, no leading : datomic.error/arg (error.clj:57)

(d/pull (d/db root-dbconn) ['*] (d/tempid :db.part/user -1))
=> #:db{:id -9223350046622220289}

(d/pull (d/db root-dbconn) ['*] (d/tempid :db.part/user "a"))
ClassCastException java.lang.String cannot be cast to java.lang.Number
datomic.api/tempid (api.clj:41)