CLJS-3125: set! emits invalid js when used as expression

Author: mfikes

src/main/clojure/cljs/compiler.cljc

@@ -1237,7 +1237,7 @@
 
 (defmethod emit* :set!
   [{:keys [target val env]}]
-  (emit-wrap env (emits target " = " val)))
+  (emit-wrap env (emits "(" target " = " val ")")))
 
 (defn emit-global-export [ns-name global-exports lib]
   (emitln (munge ns-name) "."

src/test/cljs/cljs/specials_test.cljs

@@ -0,0 +1,25 @@
+;; Copyright (c) Rich Hickey. All rights reserved.
+;; The use and distribution terms for this software are covered by the
+;; Eclipse Public License 1.0 (http://opensource.org/licenses/eclipse-1.0.php)
+;; which can be found in the file epl-v10.html at the root of this distribution.
+;; By using this software in any fashion, you are agreeing to be bound by
+;; the terms of this license.
+;; You must not remove this notice, or any other, from this software.
+
+(ns cljs.specials-test
+  (:require [cljs.test :refer-macros [deftest is]]))
+
+(defprotocol IFoo3125
+  (-mutate [this]))
+
+(defrecord Foo3125 [^:mutable x]
+  IFoo3125
+  (-mutate [this] (* 3 (set! x (inc x)))))
+
+(def ^:dynamic *test-cljs-3125* 4)
+
+(deftest test-cljs-3125
+  (is (== 12 (let [o #js {}] (* 6 (set! (.-a o) 2)))))
+  (is (== 12 (let [o #js {}] (* 6 (set! o -a 2)))))
+  (is (== 15 (* 3 (set! *test-cljs-3125* (inc *test-cljs-3125*)))))
+  (is (== 18 (-mutate (->Foo3125 5)))))

src/test/cljs/test_runner.cljs

@@ -37,6 +37,7 @@
             [cljs.pprint]
             [cljs.pprint-test]
             [cljs.spec-test]
+            [cljs.specials-test]
             [cljs.spec.test-test]
             [cljs.clojure-alias-test]
             [cljs.hash-map-test]
@@ -85,6 +86,7 @@
   'cljs.import-test
   'cljs.pprint
   'cljs.spec-test
+  'cljs.specials-test
   'cljs.spec.test-test
   'cljs.clojure-alias-test
   'cljs.hash-map-test

src/test/self/self_parity/test.cljs

@@ -303,6 +303,7 @@
                  [cljs.pprint]
                  [cljs.pprint-test]
                  [cljs.spec-test]
+                 [cljs.specials-test]
                  [cljs.spec.test-test]
                  [cljs.clojure-alias-test]
                  [cljs.hash-map-test]
@@ -351,6 +352,7 @@
              'cljs.pprint
              'cljs.pprint-test
              'cljs.spec-test
+             'cljs.specials-test
              'cljs.spec.test-test
              'cljs.clojure-alias-test
              'cljs.hash-map-test