CLJS-2736: Elements returned from sets as functions are not the actual elements in the set

Author: swannodette

src/main/cljs/cljs/core.cljs

@@ -9102,8 +9102,8 @@ reduces them without incurring seq initialization"
   (-lookup [coll v]
     (-lookup coll v nil))
   (-lookup [coll v not-found]
-    (if (-contains-key? hash-map v)
-      v
+    (if-let [entry (-find hash-map v)]
+      (key entry)
       not-found))
 
   ISet

src/test/cljs/cljs/collections_test.cljs

@@ -8,7 +8,7 @@
 
 (ns cljs.collections-test
   (:refer-clojure :exclude [iter])
-  (:require [cljs.test :refer-macros [deftest testing is are]]
+  (:require [cljs.test :refer-macros [deftest testing is are run-tests]]
             [clojure.string :as s]
             [clojure.set :as set]))
 
@@ -998,3 +998,13 @@
     (is (not (realized? xs)))
     (is (not (realized? ys)))
     (is (= () xs ys))))
+
+(deftest test-cljs-2736
+  (let [s #{(with-meta [:a] {:n 42})}]
+    (is (= {:n 42} (meta (s [:a]))))))
+
+(comment
+
+  (run-tests)
+
+  )