1 use std::marker::PhantomPinned; 2 3 use pin_project::pin_project; 4 5 #[pin_project] 6 struct S<T> { 7 #[pin] 8 f: T, 9 } 10 11 struct __S {} 12 13 impl Unpin for __S {} 14 is_unpin<T: Unpin>()15fn is_unpin<T: Unpin>() {} 16 main()17fn main() { 18 is_unpin::<S<PhantomPinned>>(); //~ ERROR E0277 19 } 20