* remove the circularity that str has with IndexedSeq

Author: swannodette

src/main/cljs/cljs/core.cljs

@@ -3050,16 +3050,27 @@ reduces them without incurring seq initialization"
 (defn str
   "With no args, returns the empty string. With one arg x, returns
   x.toString().  (str nil) returns the empty string. With more than
-  one arg, returns the concatenation of the str values of the args."
-  ([] "")
-  ([x] (if (nil? x)
-         ""
-         (.join #js [x] "")))
-  ([x & ys]
-    (loop [sb (StringBuffer. (str x)) more ys]
-      (if more
-        (recur (. sb  (append (str (first more)))) (next more))
-        (.toString sb)))))
+  one arg, returns the concatenation of the str values of the args.
+  @param x
+  @param {...*} var_args"
+  [x var-args]
+  (cond
+    ;; works whether x is undefined or null (cljs nil)
+    (nil? x) ""
+    ;; if we have no more parameters, return
+    (undefined? var-args) (.join #js [x] "")
+    ;; var arg case without relying on CLJS fn machinery which creates
+    ;; a circularity via IndexedSeq
+    :else
+    (let [sb   (StringBuffer.)
+          args (js-arguments)
+          len  (alength args)]
+      (loop [i 1]
+        (if (< i len)
+          (do
+            (.append sb (cljs.core/str (aget args i)))
+            (recur (inc i)))
+          (.toString sb))))))
 
 (defn subs
   "Returns the substring of s beginning at start inclusive, and ending

src/main/clojure/cljs/core.cljc

@@ -854,12 +854,12 @@
   ([x]
    (if (typed-expr? &env x '#{string})
      x
-     (string-expr (core/list 'js* "cljs.core.str.cljs$core$IFn$_invoke$arity$1(~{})" x))))
+     (string-expr (core/list 'js* "cljs.core.str(~{})" x))))
   ([x & ys]
    (core/let [interpolate (core/fn [x]
                             (if (typed-expr? &env x '#{string clj-nil})
                               "~{}"
-                              "cljs.core.str.cljs$core$IFn$_invoke$arity$1(~{})"))
+                              "cljs.core.str(~{})"))
               strs        (core/->> (core/list* x ys)
                             (map interpolate)
                             (interpose ",")