diff --git a/src/clj/cljs/compiler.clj b/src/clj/cljs/compiler.clj
index 01f23ce8fe..26dd5e64cc 100644
--- a/src/clj/cljs/compiler.clj
+++ b/src/clj/cljs/compiler.clj
@@ -421,7 +421,7 @@
 
 (defn safe-test? [e]
   (let [tag (infer-tag e)]
-    (or (= tag 'boolean)
+    (or (#{'boolean 'seq} tag)
         (when (= (:op e) :constant)
           (let [form (:form e)]
             (not (or (and (string? form) (= form ""))
diff --git a/src/cljs/cljs/core.cljs b/src/cljs/cljs/core.cljs
index 5621ad5d2d..5119222566 100644
--- a/src/cljs/cljs/core.cljs
+++ b/src/cljs/cljs/core.cljs
@@ -570,12 +570,12 @@ reduces them without incurring seq initialization"
   IHash
   (-hash [coll] (hash-coll coll)))
 
-(defn seq
+(defn ^seq seq
   "Returns a seq on the collection. If the collection is
   empty, returns nil.  (seq nil) returns nil. seq also works on
   Strings."
   [coll]
-  (if-not (nil? coll)
+  (when-not (nil? coll)
     (if (satisfies? ASeq coll)
       coll
       (-seq coll))))
@@ -591,7 +591,7 @@ reduces them without incurring seq initialization"
         (when-not (nil? s)
           (-first s))))))
 
-(defn rest
+(defn ^seq rest
   "Returns a possibly empty seq of the items after the first. Calls seq on its
   argument."
   [coll]
@@ -604,7 +604,7 @@ reduces them without incurring seq initialization"
           ())))
     ()))
 
-(defn next
+(defn ^seq next
   "Returns a seq of the items after the first. Calls seq on its
   argument.  If there are no more items, returns nil"
   [coll]