diff --git a/src/main/clojure/cljs/core.cljc b/src/main/clojure/cljs/core.cljc
index 8ef2a3bb4b..d9da4618fa 100644
--- a/src/main/clojure/cljs/core.cljc
+++ b/src/main/clojure/cljs/core.cljc
@@ -755,7 +755,8 @@
           (iterate (core/fn [[p b]]
                      (if (core/== 2147483648 b)
                        [(core/inc p) 1]
-                       [p (core/bit-shift-left b 1)]))
+                       [p #?(:clj  (core/bit-shift-left b 1)
+                             :cljs (core/* 2 b))]))
                    [0 1])))
 
 (def fast-path-protocol-partitions-count
diff --git a/src/test/cljs/cljs/core_test.cljs b/src/test/cljs/cljs/core_test.cljs
index a6211735a9..aff60a69c0 100644
--- a/src/test/cljs/cljs/core_test.cljs
+++ b/src/test/cljs/cljs/core_test.cljs
@@ -1899,6 +1899,9 @@
 (defrecord C [a b c])
 (defrecord A' [x])
 (defrecord B' [x])
+(defrecord FooComparable [x]
+  IComparable
+  (-compare [_ o] (compare x (.-x o))))
 
 (deftest test-records
   (let [fred (Person. "Fred" "Mertz")
@@ -1939,7 +1942,8 @@
       (is (= (set (keys (dissoc more-letters :d))) #{:a :b :c :e :f}))
       (is (= (set (keys (dissoc more-letters :d :e))) #{:a :b :c :f}))
       (is (= (set (keys (dissoc more-letters :d :e :f))) #{:a :b :c}))
-      (is (not= (A'. nil) (B'. nil))))))
+      (is (not= (A'. nil) (B'. nil)))
+      (is (satisfies? IComparable (->FooComparable 1))))))
 
 (deftype FnLike []
   IFn