Skip writes to |f.arguments| if |f| cannot have an argsobj (bug 592927, r=brendan).

--HG--
extra : rebase_source : 8e53abcec2739585d5b3ee2fd0c80f5532a685e0

js/src/jsfun.cpp

@@ -576,7 +576,9 @@ ArgSetter(JSContext *cx, JSObject *obj, jsid id, Value *vp)
         if (arg < obj->getArgsInitialLength()) {
             JSStackFrame *fp = (JSStackFrame *) obj->getPrivate();
             if (fp) {
-                fp->canonicalActualArg(arg) = *vp;
+                JSScript *script = fp->functionScript();
+                if (script->usesArguments)
+                    fp->canonicalActualArg(arg) = *vp;
                 return true;
             }
         }

js/src/trace-test/tests/basic/bug592927.js

@@ -0,0 +1,27 @@
+// vim: set ts=4 sw=4 tw=99 et:
+function f(x, y) {
+    x(f);
+    assertEq(y, "hello");
+}
+
+function g(x) {
+    assertEq(x.arguments[1], "hello");
+    x.arguments[1] = "bye";
+    assertEq(x.arguments[1], "hello");
+}
+
+function f2(x, y) {
+    arguments;
+    x(f2);
+    assertEq(y, "bye");
+}
+
+function g2(x) {
+    assertEq(x.arguments[1], "hello");
+    x.arguments[1] = "bye";
+    assertEq(x.arguments[1], "bye");
+}
+
+f(g, "hello");
+f2(g2, "hello");
+