[ot]

`NoDestructor` just ensures that the destructor is not called on the wrapped object, but you still need to manage the lifetime. If you look at the example, its recommended usage is with a function static. In other words, it's a utility to implement leaky Meyers' singletons.

std::launder is a bit weird here. Technically it should be used every time you use placement new but access the object by casting the pointer to its storage (which NoDestructor does). However, very little code actually uses it. For example, every implementation of std::optional should use it? But when you do, it actually prevents important compiler optimizations that make std::optional a zero-cost abstraction (or it did last time I looked into this).