//@ edition:2018 #![forbid(internal_features, unsafe_code)] #![feature(unsafe_pin_internals)] //~^ ERROR the feature `unsafe_pin_internals` is internal to the compiler or standard library use core::{marker::PhantomPinned, pin::Pin}; /// The `unsafe_pin_internals` is indeed unsound. fn non_unsafe_pin_new_unchecked(pointer: &mut T) -> Pin<&mut T> { Pin { __pointer: pointer } } fn main() { let mut self_referential = PhantomPinned; let _: Pin<&mut PhantomPinned> = non_unsafe_pin_new_unchecked(&mut self_referential); }