1 use core::cell::RefCell;
2 use core::mem::{self, MaybeUninit};
3 use core::num::NonZeroUsize;
6 use std::fmt::{Debug, Display};
9 fn test_const_from_raw_parts() {
10 const SLICE: &[u8] = &[1, 2, 3, 4];
11 const FROM_RAW: &[u8] = unsafe { &*slice_from_raw_parts(SLICE.as_ptr(), SLICE.len()) };
12 assert_eq!(SLICE, FROM_RAW);
14 let slice = &[1, 2, 3, 4, 5];
15 let from_raw = unsafe { &*slice_from_raw_parts(slice.as_ptr(), 2) };
16 assert_eq!(&slice[..2], from_raw);
27 let mut p = Pair { fst: 10, snd: 20 };
28 let pptr: *mut Pair = &mut p;
29 let iptr: *mut isize = pptr as *mut isize;
30 assert_eq!(*iptr, 10);
32 assert_eq!(*iptr, 30);
33 assert_eq!(p.fst, 30);
35 *pptr = Pair { fst: 50, snd: 60 };
36 assert_eq!(*iptr, 50);
37 assert_eq!(p.fst, 50);
38 assert_eq!(p.snd, 60);
40 let v0 = vec![32000u16, 32001u16, 32002u16];
41 let mut v1 = vec![0u16, 0u16, 0u16];
43 copy(v0.as_ptr().offset(1), v1.as_mut_ptr().offset(1), 1);
44 assert!((v1[0] == 0u16 && v1[1] == 32001u16 && v1[2] == 0u16));
45 copy(v0.as_ptr().offset(2), v1.as_mut_ptr(), 1);
46 assert!((v1[0] == 32002u16 && v1[1] == 32001u16 && v1[2] == 0u16));
47 copy(v0.as_ptr(), v1.as_mut_ptr().offset(2), 1);
48 assert!((v1[0] == 32002u16 && v1[1] == 32001u16 && v1[2] == 32000u16));
54 let p: *const isize = null();
57 let q = p.wrapping_offset(1);
58 assert!(!q.is_null());
60 let mp: *mut isize = null_mut();
61 assert!(mp.is_null());
63 let mq = mp.wrapping_offset(1);
64 assert!(!mq.is_null());
66 // Pointers to unsized types -- slices
67 let s: &mut [u8] = &mut [1, 2, 3];
68 let cs: *const [u8] = s;
69 assert!(!cs.is_null());
71 let ms: *mut [u8] = s;
72 assert!(!ms.is_null());
74 let cz: *const [u8] = &[];
75 assert!(!cz.is_null());
77 let mz: *mut [u8] = &mut [];
78 assert!(!mz.is_null());
80 let ncs: *const [u8] = null::<[u8; 3]>();
81 assert!(ncs.is_null());
83 let nms: *mut [u8] = null_mut::<[u8; 3]>();
84 assert!(nms.is_null());
86 // Pointers to unsized types -- trait objects
87 let ci: *const dyn ToString = &3;
88 assert!(!ci.is_null());
90 let mi: *mut dyn ToString = &mut 3;
91 assert!(!mi.is_null());
93 let nci: *const dyn ToString = null::<isize>();
94 assert!(nci.is_null());
96 let nmi: *mut dyn ToString = null_mut::<isize>();
97 assert!(nmi.is_null());
102 let ec: *const Extern = null::<Extern>();
103 assert!(ec.is_null());
105 let em: *mut Extern = null_mut::<Extern>();
106 assert!(em.is_null());
112 let p: *const isize = null();
113 assert_eq!(p.as_ref(), None);
115 let q: *const isize = &2;
116 assert_eq!(q.as_ref().unwrap(), &2);
118 let p: *mut isize = null_mut();
119 assert_eq!(p.as_ref(), None);
121 let q: *mut isize = &mut 2;
122 assert_eq!(q.as_ref().unwrap(), &2);
124 // Lifetime inference
127 let p = &u as *const isize;
128 assert_eq!(p.as_ref().unwrap(), &2);
131 // Pointers to unsized types -- slices
132 let s: &mut [u8] = &mut [1, 2, 3];
133 let cs: *const [u8] = s;
134 assert_eq!(cs.as_ref(), Some(&*s));
136 let ms: *mut [u8] = s;
137 assert_eq!(ms.as_ref(), Some(&*s));
139 let cz: *const [u8] = &[];
140 assert_eq!(cz.as_ref(), Some(&[][..]));
142 let mz: *mut [u8] = &mut [];
143 assert_eq!(mz.as_ref(), Some(&[][..]));
145 let ncs: *const [u8] = null::<[u8; 3]>();
146 assert_eq!(ncs.as_ref(), None);
148 let nms: *mut [u8] = null_mut::<[u8; 3]>();
149 assert_eq!(nms.as_ref(), None);
151 // Pointers to unsized types -- trait objects
152 let ci: *const dyn ToString = &3;
153 assert!(ci.as_ref().is_some());
155 let mi: *mut dyn ToString = &mut 3;
156 assert!(mi.as_ref().is_some());
158 let nci: *const dyn ToString = null::<isize>();
159 assert!(nci.as_ref().is_none());
161 let nmi: *mut dyn ToString = null_mut::<isize>();
162 assert!(nmi.as_ref().is_none());
169 let p: *mut isize = null_mut();
170 assert!(p.as_mut() == None);
172 let q: *mut isize = &mut 2;
173 assert!(q.as_mut().unwrap() == &mut 2);
175 // Lifetime inference
178 let p = &mut u as *mut isize;
179 assert!(p.as_mut().unwrap() == &mut 2);
182 // Pointers to unsized types -- slices
183 let s: &mut [u8] = &mut [1, 2, 3];
184 let ms: *mut [u8] = s;
185 assert_eq!(ms.as_mut(), Some(&mut [1, 2, 3][..]));
187 let mz: *mut [u8] = &mut [];
188 assert_eq!(mz.as_mut(), Some(&mut [][..]));
190 let nms: *mut [u8] = null_mut::<[u8; 3]>();
191 assert_eq!(nms.as_mut(), None);
193 // Pointers to unsized types -- trait objects
194 let mi: *mut dyn ToString = &mut 3;
195 assert!(mi.as_mut().is_some());
197 let nmi: *mut dyn ToString = null_mut::<isize>();
198 assert!(nmi.as_mut().is_none());
203 fn test_ptr_addition() {
205 let xs = vec![5; 16];
206 let mut ptr = xs.as_ptr();
207 let end = ptr.offset(16);
215 let mut m_ptr = xs_mut.as_mut_ptr();
216 let m_end = m_ptr.offset(16);
218 while m_ptr < m_end {
220 m_ptr = m_ptr.offset(1);
223 assert!(xs_mut == vec![10; 16]);
228 fn test_ptr_subtraction() {
230 let xs = vec![0, 1, 2, 3, 4, 5, 6, 7, 8, 9];
232 let ptr = xs.as_ptr();
235 assert_eq!(*(ptr.offset(idx as isize)), idx as isize);
240 let m_start = xs_mut.as_mut_ptr();
241 let mut m_ptr = m_start.offset(9);
245 if m_ptr == m_start {
248 m_ptr = m_ptr.offset(-1);
251 assert_eq!(xs_mut, [0, 2, 4, 6, 8, 10, 12, 14, 16, 18]);
256 fn test_set_memory() {
257 let mut xs = [0u8; 20];
258 let ptr = xs.as_mut_ptr();
260 write_bytes(ptr, 5u8, xs.len());
262 assert!(xs == [5u8; 20]);
266 fn test_set_memory_const() {
267 const XS: [u8; 20] = {
268 let mut xs = [0u8; 20];
269 let ptr = xs.as_mut_ptr();
271 ptr.write_bytes(5u8, xs.len());
276 assert!(XS == [5u8; 20]);
280 fn test_unsized_nonnull() {
281 let xs: &[i32] = &[1, 2, 3];
282 let ptr = unsafe { NonNull::new_unchecked(xs as *const [i32] as *mut [i32]) };
283 let ys = unsafe { ptr.as_ref() };
284 let zs: &[i32] = &[1, 2, 3];
289 fn test_const_nonnull_new() {
291 assert!(NonNull::new(core::ptr::null_mut::<()>()).is_none());
293 let value = &mut 0u32;
294 let mut ptr = NonNull::new(value).unwrap();
295 unsafe { *ptr.as_mut() = 42 };
297 let reference = unsafe { &*ptr.as_ref() };
298 assert!(*reference == *value);
299 assert!(*reference == 42);
304 #[cfg(unix)] // printf may not be available on other platforms
305 #[allow(deprecated)] // For SipHasher
306 pub fn test_variadic_fnptr() {
308 use core::hash::{Hash, SipHasher};
310 // This needs to use the correct function signature even though it isn't called as some
311 // codegen backends make it UB to declare a function with multiple conflicting signatures
312 // (like LLVM) while others straight up return an error (like Cranelift).
313 fn printf(_: *const ffi::c_char, ...) -> ffi::c_int;
315 let p: unsafe extern "C" fn(*const ffi::c_char, ...) -> ffi::c_int = printf;
319 let mut s = SipHasher::new();
320 assert_eq!(p.hash(&mut s), q.hash(&mut s));
324 fn write_unaligned_drop() {
326 static DROPS: RefCell<Vec<u32>> = RefCell::new(Vec::new());
331 impl Drop for Dropper {
333 DROPS.with(|d| d.borrow_mut().push(self.0));
339 let mut t = Dropper(1);
341 write_unaligned(&mut t, c);
344 DROPS.with(|d| assert_eq!(*d.borrow(), [0]));
348 fn align_offset_zst() {
349 // For pointers of stride = 0, the pointer is already aligned or it cannot be aligned at
350 // all, because no amount of elements will align the pointer.
353 assert_eq!(ptr::invalid::<()>(p).align_offset(p), 0);
355 assert_eq!(ptr::invalid::<()>(p + 1).align_offset(p), !0);
357 p = (p + 1).next_power_of_two();
362 fn align_offset_stride_one() {
363 // For pointers of stride = 1, the pointer can always be aligned. The offset is equal to
367 for ptr in 1..2 * align {
368 let expected = ptr % align;
369 let offset = if expected == 0 { 0 } else { align - expected };
371 ptr::invalid::<u8>(ptr).align_offset(align),
373 "ptr = {}, align = {}, size = 1",
378 align = (align + 1).next_power_of_two();
383 fn align_offset_various_strides() {
384 unsafe fn test_stride<T>(ptr: *const T, align: usize) -> bool {
385 let numptr = ptr as usize;
386 let mut expected = usize::MAX;
387 // Naive but definitely correct way to find the *first* aligned element of stride::<T>.
389 if (numptr + el * ::std::mem::size_of::<T>()) % align == 0 {
394 let got = ptr.align_offset(align);
397 "aligning {:p} (with stride of {}) to {}, expected {}, got {}",
399 ::std::mem::size_of::<T>(),
409 // For pointers of stride != 1, we verify the algorithm against the naivest possible
414 let limit = if cfg!(miri) { 32 } else { 1024 };
415 while align < limit {
416 for ptr in 1usize..4 * align {
420 x |= test_stride::<A3>(ptr::invalid::<A3>(ptr), align);
423 x |= test_stride::<A4>(ptr::invalid::<A4>(ptr), align);
427 x |= test_stride::<A5>(ptr::invalid::<A5>(ptr), align);
431 x |= test_stride::<A6>(ptr::invalid::<A6>(ptr), align);
434 struct A7(u32, u16, u8);
435 x |= test_stride::<A7>(ptr::invalid::<A7>(ptr), align);
439 x |= test_stride::<A8>(ptr::invalid::<A8>(ptr), align);
442 struct A9(u32, u32, u8);
443 x |= test_stride::<A9>(ptr::invalid::<A9>(ptr), align);
446 struct A10(u32, u32, u16);
447 x |= test_stride::<A10>(ptr::invalid::<A10>(ptr), align);
449 x |= test_stride::<u32>(ptr::invalid::<u32>(ptr), align);
450 x |= test_stride::<u128>(ptr::invalid::<u128>(ptr), align);
453 align = (align + 1).next_power_of_two();
461 let ptr1: *mut i32 = &mut a[1];
462 let ptr2: *mut i32 = &mut a[3];
464 assert_eq!(ptr2.offset_from(ptr1), 2);
465 assert_eq!(ptr1.offset_from(ptr2), -2);
466 assert_eq!(ptr1.offset(2), ptr2);
467 assert_eq!(ptr2.offset(-2), ptr1);
474 struct Pair<A, B: ?Sized>(A, B);
478 let () = metadata(&());
479 let () = metadata(&Unit);
480 let () = metadata(&4_u32);
481 let () = metadata(&String::new());
482 let () = metadata(&Some(4_u32));
483 let () = metadata(&ptr_metadata);
484 let () = metadata(&|| {});
485 let () = metadata(&[4, 7]);
486 let () = metadata(&(4, String::new()));
487 let () = metadata(&Pair(4, String::new()));
488 let () = metadata(ptr::null::<()>() as *const Extern);
489 let () = metadata(ptr::null::<()>() as *const <&u32 as std::ops::Deref>::Target);
491 assert_eq!(metadata("foo"), 3_usize);
492 assert_eq!(metadata(&[4, 7][..]), 2_usize);
494 let dst_tuple: &(bool, [u8]) = &(true, [0x66, 0x6F, 0x6F]);
495 let dst_struct: &Pair<bool, [u8]> = &Pair(true, [0x66, 0x6F, 0x6F]);
496 assert_eq!(metadata(dst_tuple), 3_usize);
497 assert_eq!(metadata(dst_struct), 3_usize);
499 let dst_tuple: &(bool, str) = std::mem::transmute(dst_tuple);
500 let dst_struct: &Pair<bool, str> = std::mem::transmute(dst_struct);
501 assert_eq!(&dst_tuple.1, "foo");
502 assert_eq!(&dst_struct.1, "foo");
503 assert_eq!(metadata(dst_tuple), 3_usize);
504 assert_eq!(metadata(dst_struct), 3_usize);
507 let vtable_1: DynMetadata<dyn Debug> = metadata(&4_u16 as &dyn Debug);
508 let vtable_2: DynMetadata<dyn Display> = metadata(&4_u16 as &dyn Display);
509 let vtable_3: DynMetadata<dyn Display> = metadata(&4_u32 as &dyn Display);
510 let vtable_4: DynMetadata<dyn Display> = metadata(&(true, 7_u32) as &(bool, dyn Display));
511 let vtable_5: DynMetadata<dyn Display> =
512 metadata(&Pair(true, 7_u32) as &Pair<bool, dyn Display>);
514 let address_1: *const () = std::mem::transmute(vtable_1);
515 let address_2: *const () = std::mem::transmute(vtable_2);
516 let address_3: *const () = std::mem::transmute(vtable_3);
517 let address_4: *const () = std::mem::transmute(vtable_4);
518 let address_5: *const () = std::mem::transmute(vtable_5);
519 // Different trait => different vtable pointer
520 assert_ne!(address_1, address_2);
521 // Different erased type => different vtable pointer
522 assert_ne!(address_2, address_3);
523 // Same erased type and same trait => same vtable pointer
524 assert_eq!(address_3, address_4);
525 assert_eq!(address_3, address_5);
530 fn ptr_metadata_bounds() {
531 fn metadata_eq_method_address<T: ?Sized>() -> usize {
532 // The `Metadata` associated type has an `Ord` bound, so this is valid:
533 <<T as Pointee>::Metadata as PartialEq>::eq as usize
535 // "Synthetic" trait impls generated by the compiler like those of `Pointee`
536 // are not checked for bounds of associated type.
537 // So with a buggy libcore we could have both:
538 // * `<dyn Display as Pointee>::Metadata == DynMetadata`
539 // * `DynMetadata: !PartialEq`
540 // … and cause an ICE here:
541 metadata_eq_method_address::<dyn Display>();
543 // For this reason, let’s check here that bounds are satisfied:
545 let _ = static_assert_expected_bounds_for_metadata::<()>;
546 let _ = static_assert_expected_bounds_for_metadata::<usize>;
547 let _ = static_assert_expected_bounds_for_metadata::<DynMetadata<dyn Display>>;
548 fn _static_assert_associated_type<T: ?Sized>() {
549 let _ = static_assert_expected_bounds_for_metadata::<<T as Pointee>::Metadata>;
552 fn static_assert_expected_bounds_for_metadata<Meta>()
554 // Keep this in sync with the associated type in `library/core/src/ptr/metadata.rs`
555 Meta: Copy + Send + Sync + Ord + std::hash::Hash + Unpin,
564 struct Something([u8; 47]);
566 let value = Something([0; 47]);
567 let trait_object: &dyn Debug = &value;
568 let meta = metadata(trait_object);
570 assert_eq!(meta.size_of(), 64);
571 assert_eq!(meta.size_of(), std::mem::size_of::<Something>());
572 assert_eq!(meta.align_of(), 32);
573 assert_eq!(meta.align_of(), std::mem::align_of::<Something>());
574 assert_eq!(meta.layout(), std::alloc::Layout::new::<Something>());
576 assert!(format!("{meta:?}").starts_with("DynMetadata(0x"));
580 fn from_raw_parts() {
581 let mut value = 5_u32;
582 let address = &mut value as *mut _ as *mut ();
583 let trait_object: &dyn Display = &mut value;
584 let vtable = metadata(trait_object);
585 let trait_object = NonNull::from(trait_object);
587 assert_eq!(ptr::from_raw_parts(address, vtable), trait_object.as_ptr());
588 assert_eq!(ptr::from_raw_parts_mut(address, vtable), trait_object.as_ptr());
589 assert_eq!(NonNull::from_raw_parts(NonNull::new(address).unwrap(), vtable), trait_object);
591 let mut array = [5_u32, 5, 5, 5, 5];
592 let address = &mut array as *mut _ as *mut ();
593 let array_ptr = NonNull::from(&mut array);
594 let slice_ptr = NonNull::from(&mut array[..]);
596 assert_eq!(ptr::from_raw_parts(address, ()), array_ptr.as_ptr());
597 assert_eq!(ptr::from_raw_parts_mut(address, ()), array_ptr.as_ptr());
598 assert_eq!(NonNull::from_raw_parts(NonNull::new(address).unwrap(), ()), array_ptr);
600 assert_eq!(ptr::from_raw_parts(address, 5), slice_ptr.as_ptr());
601 assert_eq!(ptr::from_raw_parts_mut(address, 5), slice_ptr.as_ptr());
602 assert_eq!(NonNull::from_raw_parts(NonNull::new(address).unwrap(), 5), slice_ptr);
607 let foo = ThinBox::<dyn Display>::new(4);
608 assert_eq!(foo.to_string(), "4");
610 let bar = ThinBox::<dyn Display>::new(7);
611 assert_eq!(bar.to_string(), "7");
613 // A slightly more interesting library that could be built on top of metadata APIs.
615 // * It could be generalized to any `T:Â ?Sized` (not just trait object)
616 // if `{size,align}_of_for_meta<T:Â ?Sized>(T::Metadata)` are added.
617 // * Constructing a `ThinBox` without consuming and deallocating a `Box`
618 // requires either the unstable `Unsize` marker trait,
619 // or the unstable `unsized_locals`Â language feature,
620 // or taking `&dyn T` and restricting to `T: Copy`.
623 use std::marker::PhantomData;
627 T: ?Sized + Pointee<Metadata = DynMetadata<T>>,
629 ptr: NonNull<DynMetadata<T>>,
630 phantom: PhantomData<T>,
635 T: ?Sized + Pointee<Metadata = DynMetadata<T>>,
637 pub fn new<Value: std::marker::Unsize<T>>(value: Value) -> Self {
638 let unsized_: &T = &value;
639 let meta = metadata(unsized_);
640 let meta_layout = Layout::for_value(&meta);
641 let value_layout = Layout::for_value(&value);
642 let (layout, offset) = meta_layout.extend(value_layout).unwrap();
643 // `DynMetadata` is pointer-sized:
644 assert!(layout.size() > 0);
645 // If `ThinBox<T>` is generalized to any `T: ?Sized`,
646 // handle ZSTs with a dangling pointer without going through `alloc()`,
647 // like `Box<T>` does.
649 let ptr = NonNull::new(alloc(layout))
650 .unwrap_or_else(|| handle_alloc_error(layout))
651 .cast::<DynMetadata<T>>();
652 ptr.as_ptr().write(meta);
653 ptr.as_ptr().byte_add(offset).cast::<Value>().write(value);
654 Self { ptr, phantom: PhantomData }
658 fn meta(&self) -> DynMetadata<T> {
659 unsafe { *self.ptr.as_ref() }
662 fn layout(&self) -> (Layout, usize) {
663 let meta = self.meta();
664 Layout::for_value(&meta).extend(meta.layout()).unwrap()
667 fn value_ptr(&self) -> *const T {
668 let (_, offset) = self.layout();
669 let data_ptr = unsafe { self.ptr.cast::<u8>().as_ptr().add(offset) };
670 ptr::from_raw_parts(data_ptr.cast(), self.meta())
673 fn value_mut_ptr(&mut self) -> *mut T {
674 let (_, offset) = self.layout();
675 // FIXME: can this line be shared with the same in `value_ptr()`
676 // without upsetting Stacked Borrows?
677 let data_ptr = unsafe { self.ptr.cast::<u8>().as_ptr().add(offset) };
678 from_raw_parts_mut(data_ptr.cast(), self.meta())
682 impl<T> std::ops::Deref for ThinBox<T>
684 T: ?Sized + Pointee<Metadata = DynMetadata<T>>,
688 fn deref(&self) -> &T {
689 unsafe { &*self.value_ptr() }
693 impl<T> std::ops::DerefMut for ThinBox<T>
695 T: ?Sized + Pointee<Metadata = DynMetadata<T>>,
697 fn deref_mut(&mut self) -> &mut T {
698 unsafe { &mut *self.value_mut_ptr() }
702 impl<T> std::ops::Drop for ThinBox<T>
704 T: ?Sized + Pointee<Metadata = DynMetadata<T>>,
707 let (layout, _) = self.layout();
709 drop_in_place::<T>(&mut **self);
710 dealloc(self.ptr.cast().as_ptr(), layout);
717 fn nonnull_tagged_pointer_with_provenance() {
718 let raw_pointer = Box::into_raw(Box::new(10));
720 let mut p = TaggedPointer::new(raw_pointer).unwrap();
721 assert_eq!(p.tag(), 0);
724 assert_eq!(p.tag(), 1);
725 assert_eq!(unsafe { *p.pointer().as_ptr() }, 10);
728 assert_eq!(p.tag(), 3);
729 assert_eq!(unsafe { *p.pointer().as_ptr() }, 10);
731 unsafe { Box::from_raw(p.pointer().as_ptr()) };
733 /// A non-null pointer type which carries several bits of metadata and maintains provenance.
735 pub struct TaggedPointer<T>(NonNull<T>);
737 impl<T> Clone for TaggedPointer<T> {
738 fn clone(&self) -> Self {
743 impl<T> Copy for TaggedPointer<T> {}
745 impl<T> TaggedPointer<T> {
746 /// The ABI-required minimum alignment of the `P` type.
747 pub const ALIGNMENT: usize = core::mem::align_of::<T>();
748 /// A mask for data-carrying bits of the address.
749 pub const DATA_MASK: usize = !Self::ADDRESS_MASK;
750 /// Number of available bits of storage in the address.
751 pub const NUM_BITS: u32 = Self::ALIGNMENT.trailing_zeros();
752 /// A mask for the non-data-carrying bits of the address.
753 pub const ADDRESS_MASK: usize = usize::MAX << Self::NUM_BITS;
755 /// Create a new tagged pointer from a possibly null pointer.
756 pub fn new(pointer: *mut T) -> Option<TaggedPointer<T>> {
757 Some(TaggedPointer(NonNull::new(pointer)?))
760 /// Consume this tagged pointer and produce a raw mutable pointer to the
762 pub fn pointer(self) -> NonNull<T> {
763 // SAFETY: The `addr` guaranteed to have bits set in the Self::ADDRESS_MASK, so the result will be non-null.
764 self.0.map_addr(|addr| unsafe {
765 NonZeroUsize::new_unchecked(addr.get() & Self::ADDRESS_MASK)
769 /// Consume this tagged pointer and produce the data it carries.
770 pub fn tag(&self) -> usize {
771 self.0.addr().get() & Self::DATA_MASK
774 /// Update the data this tagged pointer carries to a new value.
775 pub fn set_tag(&mut self, data: usize) {
777 data & Self::ADDRESS_MASK,
779 "cannot set more data beyond the lowest NUM_BITS"
781 let data = data & Self::DATA_MASK;
783 // SAFETY: This value will always be non-zero because the upper bits (from
784 // ADDRESS_MASK) will always be non-zero. This a property of the type and its
786 self.0 = self.0.map_addr(|addr| unsafe {
787 NonZeroUsize::new_unchecked((addr.get() & Self::ADDRESS_MASK) | data)
794 fn swap_copy_untyped() {
795 // We call `{swap,copy}{,_nonoverlapping}` at `bool` type on data that is not a valid bool.
796 // These should all do untyped copies, so this should work fine.
800 let ptr1 = &mut x as *mut u8 as *mut bool;
801 let ptr2 = &mut y as *mut u8 as *mut bool;
804 ptr::swap(ptr1, ptr2);
805 ptr::swap_nonoverlapping(ptr1, ptr2, 1);
811 ptr::copy(ptr1, ptr2, 1);
812 ptr::copy_nonoverlapping(ptr1, ptr2, 1);
819 fn test_const_copy() {
824 // Copy ptr1 to ptr2, bytewise.
827 &ptr1 as *const _ as *const MaybeUninit<u8>,
828 &mut ptr2 as *mut _ as *mut MaybeUninit<u8>,
829 mem::size_of::<&i32>(),
833 // Make sure they still work.
842 // Copy ptr1 to ptr2, bytewise.
844 ptr::copy_nonoverlapping(
845 &ptr1 as *const _ as *const MaybeUninit<u8>,
846 &mut ptr2 as *mut _ as *mut MaybeUninit<u8>,
847 mem::size_of::<&i32>(),
851 // Make sure they still work.