Fix next() for reverse iter, it has to call into the reverse iter hasnext

src/runtime/iterobject.cpp

@@ -91,7 +91,13 @@ Box* seqiterNext(Box* s) {
     BoxedSeqIter* self = static_cast<BoxedSeqIter*>(s);
 
     if (!self->next) {
-        Box* hasnext = seqiterHasnext(s);
+        Box* hasnext = NULL;
+        if (s->cls == seqiter_cls)
+            hasnext = seqiterHasnext(s);
+        else if (s->cls == seqreviter_cls)
+            hasnext = seqreviterHasnext(s);
+        else
+            RELEASE_ASSERT(0, "");
         if (hasnext == False)
             raiseExcHelper(StopIteration, "");
     }

test/tests/itertools_test.py

@@ -12,3 +12,5 @@ for i in xrange(10):
     for it in its:
         print it.next(),
     print
+
+print list(itertools.dropwhile(lambda x: x == 0, reversed((1, 2, 3))))

test/tests/reversed.py

@@ -20,3 +20,10 @@ print list(reversed(RevIterTest()))
 # xrange and list have __reversed__ methods
 print list(xrange(0,9).__reversed__())
 print list([1,2,3,4,5,6].__reversed__())
+
+r = reversed((1, 2, 3))
+try:
+    while True:
+        print r.next(),
+except StopIteration:
+    print ""