Merge remote-tracking branch 'origin/master'

Author: swannodette

src/main/cljs/cljs/core.cljs

@@ -6149,9 +6149,11 @@ reduces them without incurring seq initialization"
   ILookup
   (-lookup [coll k] (-lookup coll k nil))
 
-  (-lookup [coll k not-found] (if (number? k)
-                                (-nth coll k not-found)
-                                not-found))
+  (-lookup [coll k not-found]
+    (cond
+      (not ^boolean (.-edit root)) (throw (js/Error. "lookup after persistent!"))
+      (number? k) (-nth coll k not-found)
+      :else not-found))
 
   IFn
   (-invoke [coll k]

src/test/cljs/cljs/collections_test.cljs

@@ -1024,6 +1024,11 @@
               (chunk-append b 0)
               (next (chunk-cons (chunk b) nil))))))
 
+(deftest test-cljs-3124
+  (let [t (assoc! (transient []) 0 1)]
+    (persistent! t)
+    (is (= :fail (try (get t :a :not-found) (catch js/Error e :fail))))))
+
 (comment
 
   (run-tests)