CLJS-2537: Negative fractional index in contains? on array

Author: mfikes

src/main/cljs/cljs/core.cljs

@@ -1952,12 +1952,12 @@ reduces them without incurring seq initialization"
         (-lookup o k not-found)
 
         (array? o)
-        (if (and (some? k) (>= k 0) (< k (.-length o)))
+        (if (and (some? k) (< -1 k (.-length o)))
           (aget o (int k))
           not-found)
 
         (string? o)
-        (if (and (some? k) (>= k 0) (< k (.-length o)))
+        (if (and (some? k) (< -1 k (.-length o)))
           (.charAt o (int k))
           not-found)
 

src/test/cljs/cljs/core_test.cljs

@@ -1537,6 +1537,14 @@
 (deftest test-cljs-2457
   (is (thrown-with-msg? js/Error #".* is not ISeqable" (seq #js {:a 1 :b 2}))))
 
+(deftest test-cljs-2537
+  (is (true?  (contains? (to-array [7 13 41]) -0.5)))
+  (is (== 7 (get (to-array [7 13 41]) -0.5)))
+  (is (== 7 (get (to-array [7 13 41]) -0.5 :not-found)))
+  (is (true? (contains? "ab" -0.5)))
+  (is (= \a (get "ab" -0.5)))
+  (is (= \a (get "ab" -0.5 :not-found))))
+
 (deftest test-cljs-2549
   (let [tap (fn [_])]
     (add-tap tap)