1 // revisions: mirunsafeck thirunsafeck
2 // [thirunsafeck]compile-flags: -Z thir-unsafeck
4 #![feature(rustc_attrs)]
6 #[rustc_layout_scalar_valid_range_start(1)]
8 pub(crate) struct NonZero<T>(pub(crate) T);
11 const fn foo() -> NonZero<u32> {
12 let mut x = unsafe { NonZero(1) };
14 //~^ ERROR mutation of layout constrained field is unsafe
18 const fn bar() -> NonZero<u32> {
19 let mut x = unsafe { NonZero(1) };
20 unsafe { x.0 = 0 }; // this is UB