1 #![feature(rustc_attrs, const_transmute)]
2 #![allow(const_err, invalid_value)] // make sure we cannot allow away the errors tested here
6 use std::num::{NonZeroU8, NonZeroUsize};
8 const NON_NULL: NonNull<u8> = unsafe { mem::transmute(1usize) };
9 const NON_NULL_PTR: NonNull<u8> = unsafe { mem::transmute(&1) };
11 const NULL_PTR: NonNull<u8> = unsafe { mem::transmute(0usize) };
12 //~^ ERROR it is undefined behavior to use this value
14 #[deny(const_err)] // this triggers a `const_err` so validation does not even happen
15 const OUT_OF_BOUNDS_PTR: NonNull<u8> = { unsafe {
16 let ptr: &[u8; 256] = mem::transmute(&0u8); // &0 gets promoted so it does not dangle
17 // Use address-of-element for pointer arithmetic. This could wrap around to NULL!
18 let out_of_bounds_ptr = &ptr[255]; //~ ERROR any use of this value will cause an error
19 mem::transmute(out_of_bounds_ptr)
22 const NULL_U8: NonZeroU8 = unsafe { mem::transmute(0u8) };
23 //~^ ERROR it is undefined behavior to use this value
24 const NULL_USIZE: NonZeroUsize = unsafe { mem::transmute(0usize) };
25 //~^ ERROR it is undefined behavior to use this value
28 union MaybeUninit<T: Copy> {
32 const UNINIT: NonZeroU8 = unsafe { MaybeUninit { uninit: () }.init };
33 //~^ ERROR it is undefined behavior to use this value
35 // Also test other uses of rustc_layout_scalar_valid_range_start
37 #[rustc_layout_scalar_valid_range_start(10)]
38 #[rustc_layout_scalar_valid_range_end(30)]
39 struct RestrictedRange1(u32);
40 const BAD_RANGE1: RestrictedRange1 = unsafe { RestrictedRange1(42) };
41 //~^ ERROR it is undefined behavior to use this value
43 #[rustc_layout_scalar_valid_range_start(30)]
44 #[rustc_layout_scalar_valid_range_end(10)]
45 struct RestrictedRange2(u32);
46 const BAD_RANGE2: RestrictedRange2 = unsafe { RestrictedRange2(20) };
47 //~^ ERROR it is undefined behavior to use this value