More fixes

src/runtime/classobj.cpp

@@ -510,7 +510,6 @@ template Box* instanceGetattroInternal<CAPI>(Box*, Box*, GetattrRewriteArgs*) no
 template Box* instanceGetattroInternal<CXX>(Box*, Box*, GetattrRewriteArgs*);
 
 void instanceSetattroInternal(Box* _inst, Box* _attr, STOLEN(Box*) value, SetattrRewriteArgs* rewrite_args) {
-    assert(0 && "check refcounting");
     STAT_TIMER(t0, "us_timer_instance_setattro", 0);
 
     RELEASE_ASSERT(_inst->cls == instance_cls, "");
@@ -530,7 +529,9 @@ void instanceSetattroInternal(Box* _inst, Box* _attr, STOLEN(Box*) value, Setatt
             if (value->cls != classobj_cls)
                 raiseExcHelper(TypeError, "__class__ must be set to a class");
 
+            auto old_cls = inst->inst_cls;
             inst->inst_cls = static_cast<BoxedClassobj*>(value);
+            Py_DECREF(old_cls);
             return;
         }
     }

src/runtime/objmodel.cpp

@@ -6847,10 +6847,9 @@ extern "C" Box* importStar(Box* _from_module, Box* to_globals) {
     static BoxedString* all_str = getStaticString("__all__");
     Box* all = from_module->getattr(all_str);
 
-    Py_INCREF(all);
-    AUTO_DECREF(all);
-
     if (all) {
+        KEEP_ALIVE(all);
+
         static BoxedString* getitem_str = getStaticString("__getitem__");
         Box* all_getitem = typeLookup(all->cls, getitem_str);
         if (!all_getitem)

src/runtime/types.cpp

@@ -688,7 +688,7 @@ static Box* unicodeNewHelper(BoxedClass* type, Box* string, Box* encoding_obj, B
 
     Box* args;
     if (!string)
-        args = EmptyTuple;
+        args = incref(EmptyTuple);
     else if (!encoding_obj)
         args = BoxedTuple::create1(string);
     else if (!errors_obj)
@@ -696,6 +696,8 @@ static Box* unicodeNewHelper(BoxedClass* type, Box* string, Box* encoding_obj, B
     else
         args = BoxedTuple::create3(string, encoding_obj, errors_obj);
 
+    AUTO_DECREF(args);
+
     int init_code = r->cls->tp_init(r, args, NULL);
     if (init_code == -1)
         throwCAPIException();
@@ -772,7 +774,7 @@ static Box* typeCallInner(CallRewriteArgs* rewrite_args, ArgPassSpec argspec, Bo
         if (rewrite_args) {
             rewrite_args->out_rtn
                 = rewrite_args->rewriter->call(true, (void*)unicodeNewHelper, rewrite_args->arg1, rewrite_args->arg2,
-                                               rewrite_args->arg3, rewrite_args->args);
+                                               rewrite_args->arg3, rewrite_args->args)->setType(RefType::OWNED);
             rewrite_args->out_success = true;
         }