Changes for clojure.core/with-redefs

defn on Fri, 27 Apr 2012
user=> [(type []) (class [])]
[clojure.lang.PersistentVector clojure.lang.PersistentVector]

user=> (with-redefs [type (constantly java.lang.String)
                     class (constantly 10)]
         [(type [])
          (class [])])
[java.lang.String 10]