[INFER] Mark generic scripted functions as having unknown properties / return type, bug 643285.

js/src/jit-test/tests/basic/bug643285.js

@@ -0,0 +1,4 @@
+function fun() {
+    (new Function ("function ff () { actual = '' + ff. caller; } function f () { ff (); } f ();")) ('function pf' + fun + '() {}');
+}
+fun();

js/src/jsfun.cpp

@@ -2756,6 +2756,14 @@ js_InitFunctionClass(JSContext *cx, JSObject *obj)
     if (!proto)
         return NULL;
 
+    /*
+     * The default 'new' object for Function.prototype has unknown properties.
+     * This will be used for generic scripted functions, e.g. from non-compileAndGo code.
+     */
+    TypeObject *newType = proto->getNewType(cx);
+    if (!newType || !cx->markTypeObjectUnknownProperties(newType))
+        return NULL;
+
     JSFunction *fun = js_NewFunction(cx, proto, NULL, 0, JSFUN_INTERPRETED, obj, NULL, NULL, NULL);
     if (!fun)
         return NULL;