The way append allocations work makes me think that you can't have classes on the stack? That seems at odds with the design goals of making the language suitabl

The way append allocations work makes me think that you can't have classes on the stack? That seems at odds with the design goals of making the language suitable for high performance applications - I mean sure you can use structs for everything but at that point you're kinda giving up the benefit of using a modern language.