> If you really want an arena like behavior you could allocate a byte slice and use unsafe to cast it to literally any type.

Only if the type is not a pointer per se or does not contain any inner pointers.

Otherwise the garbage collector will bite you hard.

Types with inner pointers add difficulty to be sure, but it’s still possible to use them with this pattern. You have to make sure of three things to do so: 1) no pointers outside of the backing memory; 2) an explicit “clear()” function that manually nulls out inner pointers in the stored object (even inner pointers to other things in the backing slice); 3) clear() is called for all such objects that were ever stored before the backing slice is dropped and before those objects are garbage collected.