1 2 3 4 5 6
use std::cell::{Cell, UnsafeCell}; use std::marker::PhantomData; pub type NoRefUnwindSafe = PhantomData<UnsafeCell<()>>; pub type NoUnwindSafe = PhantomData<*mut NoRefUnwindSafe>; pub type Invariant<'a> = PhantomData<Cell<&'a ()>>;