src/test/ui/consts/const-eval/ub-nonnull.rs

#![feature(rustc_attrs, const_transmute)]
#![allow(const_err)] // make sure we cannot allow away the errors tested here

use std::mem;
use std::ptr::NonNull;
use std::num::{NonZeroU8, NonZeroUsize};

const NULL_PTR: NonNull<u8> = unsafe { mem::transmute(0usize) };
//~^ ERROR it is undefined behavior to use this value

const NULL_U8: NonZeroU8 = unsafe { mem::transmute(0u8) };
//~^ ERROR it is undefined behavior to use this value
const NULL_USIZE: NonZeroUsize = unsafe { mem::transmute(0usize) };
//~^ ERROR it is undefined behavior to use this value

union Transmute {
    uninit: (),
    out: NonZeroU8,
}
const UNINIT: NonZeroU8 = unsafe { Transmute { uninit: () }.out };
//~^ ERROR it is undefined behavior to use this value

// Also test other uses of rustc_layout_scalar_valid_range_start

#[rustc_layout_scalar_valid_range_start(10)]
#[rustc_layout_scalar_valid_range_end(30)]
struct RestrictedRange1(u32);
const BAD_RANGE1: RestrictedRange1 = unsafe { RestrictedRange1(42) };
//~^ ERROR it is undefined behavior to use this value

#[rustc_layout_scalar_valid_range_start(30)]
#[rustc_layout_scalar_valid_range_end(10)]
struct RestrictedRange2(u32);
const BAD_RANGE2: RestrictedRange2 = unsafe { RestrictedRange2(20) };
//~^ ERROR it is undefined behavior to use this value

fn main() {}