It's not. If you implement this strategy in a garbage collected language, you can end up with use-after-frees or double frees (though with the advantage of typ

It's not. If you implement this strategy in a garbage collected language, you can end up with use-after-frees or double frees (though with the advantage of type safety—if you use a handle of type Foo after freeing it, you'll never stomp on the memory of an object of type Bar, for any Bar≠Foo).