#![feature(rustc_attrs)] use std::cell::Cell; #[rustc_layout_scalar_valid_range_start(1)] #[repr(transparent)] pub(crate) struct NonZero(pub(crate) T); fn main() { let mut x = unsafe { NonZero(Cell::new(1)) }; let y = &x.0; //~ ERROR borrow of layout constrained field with interior mutability }