CLJS-3307: Allow extending IAssociative -contains-key? to native

Author: mfikes

src/main/cljs/cljs/core.cljs

@@ -2364,6 +2364,9 @@ reduces them without incurring seq initialization"
     (implements? IAssociative coll)
     (-contains-key? coll v)
 
+    (native-satisfies? IAssociative coll)
+    (-contains-key? coll v)
+
     (identical? (get coll v lookup-sentinel) lookup-sentinel)
     false
 

src/test/cljs/cljs/extend_to_native_test.cljs

@@ -144,3 +144,11 @@
 
 (deftest test-protocol-with-slash
   (is (=  "result" (/ ""))))
+
+(deftest test-cljs-3307
+  (extend-type object
+    IAssociative
+    (-contains-key? [_ k] (= k :valid)))
+
+  (is (contains? #js {} :valid))
+  (is (not (contains? #js {} :invalid))))