#![feature(rustc_attrs)] | |
#[rustc_layout_scalar_valid_range_start(1)] | |
#[repr(transparent)] | |
pub(crate) struct NonZero<T>(pub(crate) T); | |
fn main() {} | |
const fn foo() -> NonZero<u32> { | |
let mut x = unsafe { NonZero(1) }; | |
x.0 = 0; | |
//~^ ERROR mutation of layout constrained field is unsafe | |
x | |
} | |
const fn bar() -> NonZero<u32> { | |
let mut x = unsafe { NonZero(1) }; | |
unsafe { x.0 = 0 }; // this is UB | |
x | |
} |