src/test/ui/consts/offset_from_ub.rs

   1 // ignore-x86 FIXME: missing sysroot spans (#53081)
   2
   3 #![feature(const_raw_ptr_deref)]
   4 #![feature(const_ptr_offset_from)]
   5 #![feature(ptr_offset_from)]
   6
   7 #[repr(C)]
   8 struct Struct {
   9     data: u8,
  10     field: u8,
  11 }
  12
  13 pub const DIFFERENT_ALLOC: usize = {
  14     //~^ NOTE
  15     let uninit = std::mem::MaybeUninit::<Struct>::uninit();
  16     let base_ptr: *const Struct = &uninit as *const _ as *const Struct;
  17     let uninit2 = std::mem::MaybeUninit::<Struct>::uninit();
  18     let field_ptr: *const Struct = &uninit2 as *const _ as *const Struct;
  19     let offset = unsafe { field_ptr.offset_from(base_ptr) };
  20     offset as usize
  21 };
  22
  23 pub const NOT_PTR: usize = {
  24     //~^ NOTE
  25     unsafe { (42 as *const u8).offset_from(&5u8) as usize }
  26 };
  27
  28 pub const NOT_MULTIPLE_OF_SIZE: isize = {
  29     //~^ NOTE
  30     let data = [5u8, 6, 7];
  31     let base_ptr = data.as_ptr();
  32     let field_ptr = &data[1] as *const u8 as *const u16;
  33     unsafe { field_ptr.offset_from(base_ptr as *const u16) }
  34 };
  35
  36 pub const OFFSET_FROM_NULL: isize = {
  37     //~^ NOTE
  38     let ptr = 0 as *const u8;
  39     unsafe { ptr.offset_from(ptr) }
  40 };
  41
  42 pub const DIFFERENT_INT: isize = { // offset_from with two different integers: like DIFFERENT_ALLOC
  43     //~^ NOTE
  44     let ptr1 = 8 as *const u8;
  45     let ptr2 = 16 as *const u8;
  46     unsafe { ptr2.offset_from(ptr1) }
  47 };
  48
  49 fn main() {}