| #![feature(rustc_attrs, const_transmute)] |
| #![allow(const_err, invalid_value)] // make sure we cannot allow away the errors tested here |
| |
| use std::mem; |
| use std::ptr::NonNull; |
| use std::num::{NonZeroU8, NonZeroUsize}; |
| |
| const NON_NULL: NonNull<u8> = unsafe { mem::transmute(1usize) }; |
| const NON_NULL_PTR: NonNull<u8> = unsafe { mem::transmute(&1) }; |
| |
| const NULL_PTR: NonNull<u8> = unsafe { mem::transmute(0usize) }; |
| //~^ ERROR it is undefined behavior to use this value |
| |
| #[deny(const_err)] // this triggers a `const_err` so validation does not even happen |
| const OUT_OF_BOUNDS_PTR: NonNull<u8> = { unsafe { |
| let ptr: &[u8; 256] = mem::transmute(&0u8); // &0 gets promoted so it does not dangle |
| // Use address-of-element for pointer arithmetic. This could wrap around to NULL! |
| let out_of_bounds_ptr = &ptr[255]; //~ ERROR any use of this value will cause an error |
| mem::transmute(out_of_bounds_ptr) |
| } }; |
| |
| 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() {} |