This doesn't take into account the alignment of the type though (you'd want to use std::aligned_storage<sizeof(T), alignof(T)>), but that requires knowing enoug

This doesn't take into account the alignment of the type though (you'd want to use std::aligned_storage<sizeof(T), alignof(T)>), but that requires knowing enough about T to be able to use sizeof() and alignof(), which means no incomplete types, bringing us back to where we started.