- ASSERT(cell->structure()->classInfo()->methodTable.copyBackingStore == JSObject::copyBackingStore);
- JSObject::copyBackingStore(cell, *this);
+ if (item.token() == ButterflyCopyToken) {
+ JSObject::copyBackingStore(item.cell(), *this, ButterflyCopyToken);
+ return;
+ }
+
+ item.cell()->methodTable()->copyBackingStore(item.cell(), *this, item.token());