some fix

src/interpreter/iter.cpp

@@ -77,7 +77,7 @@ PyVar Generator::next(VM* vm) {
         throw;
     }
 
-    if(ret->type == tp_op_yield) {
+    if(ret.type == tp_op_yield) {
         // backup the context
         lf = vm->callstack.popx();
         ret = vm->s_data.popx();