Auto merge of #149775 - WaffleLapkin:core-mem-maybe-dangling, r=Mark-Simulacrum

Add `MaybeDangling` to `core`

This is the library part of adding `MaybeDangling`. Note that it doesn't actually do anything described in its docs (yet), I'll make a separate PR for that.

Tracking issue: https://github.com/rust-lang/rust/issues/118166.

r? libs
cc `@RalfJung`
This commit is contained in:
bors 2025-12-27 09:45:21 +00:00
commit 0850949213
12 changed files with 410 additions and 218 deletions

View file

@ -1,4 +1,7 @@
use crate::marker::Destruct;
use crate::cmp::Ordering;
use crate::hash::{Hash, Hasher};
use crate::marker::{Destruct, StructuralPartialEq};
use crate::mem::MaybeDangling;
use crate::ops::{Deref, DerefMut, DerefPure};
use crate::ptr;
@ -152,11 +155,11 @@ use crate::ptr;
/// [`MaybeUninit`]: crate::mem::MaybeUninit
#[stable(feature = "manually_drop", since = "1.20.0")]
#[lang = "manually_drop"]
#[derive(Copy, Clone, Debug, Default, PartialEq, Eq, PartialOrd, Ord, Hash)]
#[derive(Copy, Clone, Debug, Default)]
#[repr(transparent)]
#[rustc_pub_transparent]
pub struct ManuallyDrop<T: ?Sized> {
value: T,
value: MaybeDangling<T>,
}
impl<T> ManuallyDrop<T> {
@ -179,7 +182,7 @@ impl<T> ManuallyDrop<T> {
#[rustc_const_stable(feature = "const_manually_drop", since = "1.32.0")]
#[inline(always)]
pub const fn new(value: T) -> ManuallyDrop<T> {
ManuallyDrop { value }
ManuallyDrop { value: MaybeDangling::new(value) }
}
/// Extracts the value from the `ManuallyDrop` container.
@ -197,7 +200,7 @@ impl<T> ManuallyDrop<T> {
#[rustc_const_stable(feature = "const_manually_drop", since = "1.32.0")]
#[inline(always)]
pub const fn into_inner(slot: ManuallyDrop<T>) -> T {
slot.value
slot.value.into_inner()
}
/// Takes the value from the `ManuallyDrop<T>` container out.
@ -222,7 +225,7 @@ impl<T> ManuallyDrop<T> {
pub const unsafe fn take(slot: &mut ManuallyDrop<T>) -> T {
// SAFETY: we are reading from a reference, which is guaranteed
// to be valid for reads.
unsafe { ptr::read(&slot.value) }
unsafe { ptr::read(slot.value.as_ref()) }
}
}
@ -259,7 +262,7 @@ impl<T: ?Sized> ManuallyDrop<T> {
// SAFETY: we are dropping the value pointed to by a mutable reference
// which is guaranteed to be valid for writes.
// It is up to the caller to make sure that `slot` isn't dropped again.
unsafe { ptr::drop_in_place(&mut slot.value) }
unsafe { ptr::drop_in_place(slot.value.as_mut()) }
}
}
@ -269,7 +272,7 @@ impl<T: ?Sized> const Deref for ManuallyDrop<T> {
type Target = T;
#[inline(always)]
fn deref(&self) -> &T {
&self.value
self.value.as_ref()
}
}
@ -278,9 +281,43 @@ impl<T: ?Sized> const Deref for ManuallyDrop<T> {
impl<T: ?Sized> const DerefMut for ManuallyDrop<T> {
#[inline(always)]
fn deref_mut(&mut self) -> &mut T {
&mut self.value
self.value.as_mut()
}
}
#[unstable(feature = "deref_pure_trait", issue = "87121")]
unsafe impl<T: ?Sized> DerefPure for ManuallyDrop<T> {}
#[stable(feature = "manually_drop", since = "1.20.0")]
impl<T: ?Sized + Eq> Eq for ManuallyDrop<T> {}
#[stable(feature = "manually_drop", since = "1.20.0")]
impl<T: ?Sized + PartialEq> PartialEq for ManuallyDrop<T> {
fn eq(&self, other: &Self) -> bool {
self.value.as_ref().eq(other.value.as_ref())
}
}
#[stable(feature = "manually_drop", since = "1.20.0")]
impl<T: ?Sized> StructuralPartialEq for ManuallyDrop<T> {}
#[stable(feature = "manually_drop", since = "1.20.0")]
impl<T: ?Sized + Ord> Ord for ManuallyDrop<T> {
fn cmp(&self, other: &Self) -> Ordering {
self.value.as_ref().cmp(other.value.as_ref())
}
}
#[stable(feature = "manually_drop", since = "1.20.0")]
impl<T: ?Sized + PartialOrd> PartialOrd for ManuallyDrop<T> {
fn partial_cmp(&self, other: &Self) -> Option<Ordering> {
self.value.as_ref().partial_cmp(other.value.as_ref())
}
}
#[stable(feature = "manually_drop", since = "1.20.0")]
impl<T: ?Sized + Hash> Hash for ManuallyDrop<T> {
fn hash<H: Hasher>(&self, state: &mut H) {
self.value.as_ref().hash(state);
}
}

View file

@ -0,0 +1,113 @@
#![unstable(feature = "maybe_dangling", issue = "118166")]
use crate::{mem, ptr};
/// Allows wrapped [references] and [boxes] to dangle.
///
/// <section class="warning">
/// This type is not properly implemented yet, and the documentation below is thus not accurate.
/// </section>
///
/// That is, if a reference (or a `Box`) is wrapped in `MaybeDangling` (including when in a
/// (nested) field of a compound type wrapped in `MaybeDangling`), it does not have to follow
/// pointer aliasing rules or be dereferenceable.
///
/// This can be useful when the value can become dangling while the function holding it is still
/// executing (particularly in concurrent code). As a somewhat absurd example, consider this code:
///
/// ```rust,no_run
/// #![feature(box_as_ptr)]
/// # use std::alloc::{dealloc, Layout};
/// # use std::mem;
///
/// let mut boxed = Box::new(0_u32);
/// let ptr = Box::as_mut_ptr(&mut boxed);
///
/// // Safety: the pointer comes from a box and thus was allocated before; `box` is not used afterwards
/// unsafe { dealloc(ptr.cast(), Layout::new::<u32>()) };
///
/// mem::forget(boxed); // <-- this is UB!
/// ```
///
/// Even though the `Box`e's destructor is not run (and thus we don't have a double free bug), this
/// code is still UB. This is because when moving `boxed` into `forget`, its validity invariants
/// are asserted, causing UB since the `Box` is dangling. The safety comment is as such wrong, as
/// moving the `boxed` variable as part of the `forget` call *is* a use.
///
/// To fix this we could use `MaybeDangling`:
///
/// ```rust
/// #![feature(maybe_dangling, box_as_ptr)]
/// # use std::alloc::{dealloc, Layout};
/// # use std::mem::{self, MaybeDangling};
///
/// let mut boxed = MaybeDangling::new(Box::new(0_u32));
/// let ptr = Box::as_mut_ptr(boxed.as_mut());
///
/// // Safety: the pointer comes from a box and thus was allocated before; `box` is not used afterwards
/// unsafe { dealloc(ptr.cast(), Layout::new::<u32>()) };
///
/// mem::forget(boxed); // <-- this is OK!
/// ```
///
/// Note that the bit pattern must still be valid for the wrapped type. That is, [references]
/// (and [boxes]) still must be aligned and non-null.
///
/// Additionally note that safe code can still assume that the inner value in a `MaybeDangling` is
/// **not** dangling -- functions like [`as_ref`] and [`into_inner`] are safe. It is not sound to
/// return a dangling reference in a `MaybeDangling` to safe code. However, it *is* sound
/// to hold such values internally inside your code -- and there's no way to do that without
/// this type. Note that other types can use this type and thus get the same effect; in particular,
/// [`ManuallyDrop`] will use `MaybeDangling`.
///
/// Note that `MaybeDangling` doesn't prevent drops from being run, which can lead to UB if the
/// drop observes a dangling value. If you need to prevent drops from being run use [`ManuallyDrop`]
/// instead.
///
/// [references]: prim@reference
/// [boxes]: ../../std/boxed/struct.Box.html
/// [`into_inner`]: MaybeDangling::into_inner
/// [`as_ref`]: MaybeDangling::as_ref
/// [`ManuallyDrop`]: crate::mem::ManuallyDrop
#[repr(transparent)]
#[rustc_pub_transparent]
#[derive(Debug, Copy, Clone, Default)]
pub struct MaybeDangling<P: ?Sized>(P);
impl<P: ?Sized> MaybeDangling<P> {
/// Wraps a value in a `MaybeDangling`, allowing it to dangle.
pub const fn new(x: P) -> Self
where
P: Sized,
{
MaybeDangling(x)
}
/// Returns a reference to the inner value.
///
/// Note that this is UB if the inner value is currently dangling.
pub const fn as_ref(&self) -> &P {
&self.0
}
/// Returns a mutable reference to the inner value.
///
/// Note that this is UB if the inner value is currently dangling.
pub const fn as_mut(&mut self) -> &mut P {
&mut self.0
}
/// Extracts the value from the `MaybeDangling` container.
///
/// Note that this is UB if the inner value is currently dangling.
pub const fn into_inner(self) -> P
where
P: Sized,
{
// FIXME: replace this with `self.0` when const checker can figure out that `self` isn't actually dropped
// SAFETY: this is equivalent to `self.0`
let x = unsafe { ptr::read(&self.0) };
mem::forget(self);
x
}
}

View file

@ -19,6 +19,10 @@ mod maybe_uninit;
#[stable(feature = "maybe_uninit", since = "1.36.0")]
pub use maybe_uninit::MaybeUninit;
mod maybe_dangling;
#[unstable(feature = "maybe_dangling", issue = "118166")]
pub use maybe_dangling::MaybeDangling;
mod transmutability;
#[unstable(feature = "transmutability", issue = "99571")]
pub use transmutability::{Assume, TransmuteFrom};

View file

@ -298,7 +298,7 @@ def children_of_btree_map(map):
for i in xrange(0, length + 1):
if height > 0:
child_ptr = edges[i]["value"]["value"]
child_ptr = edges[i]["value"]["value"][ZERO_FIELD]
for child in children_of_node(child_ptr, height - 1):
yield child
if i < length:
@ -306,12 +306,12 @@ def children_of_btree_map(map):
key_type_size = keys.type.sizeof
val_type_size = vals.type.sizeof
key = (
keys[i]["value"]["value"]
keys[i]["value"]["value"][ZERO_FIELD]
if key_type_size > 0
else gdb.parse_and_eval("()")
)
val = (
vals[i]["value"]["value"]
vals[i]["value"]["value"][ZERO_FIELD]
if val_type_size > 0
else gdb.parse_and_eval("()")
)

View file

@ -35,9 +35,9 @@
</Type>
<Type Name="core::mem::manually_drop::ManuallyDrop&lt;*&gt;">
<DisplayString>{value}</DisplayString>
<DisplayString>{value.__0}</DisplayString>
<Expand>
<ExpandedItem>value</ExpandedItem>
<ExpandedItem>value.__0</ExpandedItem>
</Expand>
</Type>

View file

@ -1,6 +1,6 @@
0..1: [ SharedReadWrite<TAG> ]
0..1: [ SharedReadWrite<TAG> ]
0..1: [ SharedReadWrite<TAG> ]
0..1: [ SharedReadWrite<TAG> Unique<TAG> Unique<TAG> Unique<TAG> Unique<TAG> Unique<TAG> Unique<TAG> Unique<TAG> ]
0..1: [ SharedReadWrite<TAG> Disabled<TAG> Disabled<TAG> Disabled<TAG> Disabled<TAG> Disabled<TAG> Disabled<TAG> Disabled<TAG> SharedReadOnly<TAG> ]
0..1: [ SharedReadWrite<TAG> Unique<TAG> Unique<TAG> Unique<TAG> Unique<TAG> Unique<TAG> Unique<TAG> Unique<TAG> Unique<TAG> Unique<TAG> Unique<TAG> Unique<TAG> ]
0..1: [ SharedReadWrite<TAG> Disabled<TAG> Disabled<TAG> Disabled<TAG> Disabled<TAG> Disabled<TAG> Disabled<TAG> Disabled<TAG> Disabled<TAG> Disabled<TAG> Disabled<TAG> Disabled<TAG> SharedReadOnly<TAG> ]
0..1: [ unknown-bottom(..<TAG>) ]

View file

@ -3,304 +3,322 @@
fn vec_move(_1: Vec<impl Sized>) -> () {
debug v => _1;
let mut _0: ();
let mut _21: std::vec::IntoIter<impl Sized>;
let mut _22: std::vec::IntoIter<impl Sized>;
let mut _23: &mut std::vec::IntoIter<impl Sized>;
let mut _24: std::option::Option<impl Sized>;
let mut _25: isize;
let _27: ();
let mut _23: std::vec::IntoIter<impl Sized>;
let mut _24: &mut std::vec::IntoIter<impl Sized>;
let mut _25: std::option::Option<impl Sized>;
let mut _26: isize;
let _28: ();
scope 1 {
debug iter => _22;
let _26: impl Sized;
debug iter => _23;
let _27: impl Sized;
scope 2 {
debug x => _26;
debug x => _27;
}
}
scope 3 (inlined <Vec<impl Sized> as IntoIterator>::into_iter) {
debug self => _1;
let _2: std::mem::ManuallyDrop<std::vec::Vec<impl Sized>>;
let mut _3: *const std::alloc::Global;
let mut _8: usize;
let mut _10: *mut impl Sized;
let mut _11: *const impl Sized;
let mut _12: usize;
let _28: &std::vec::Vec<impl Sized>;
let mut _29: &std::mem::ManuallyDrop<std::vec::Vec<impl Sized>>;
let mut _30: &alloc::raw_vec::RawVec<impl Sized>;
let mut _31: &std::mem::ManuallyDrop<std::vec::Vec<impl Sized>>;
let _32: &std::vec::Vec<impl Sized>;
let mut _33: &std::mem::ManuallyDrop<std::vec::Vec<impl Sized>>;
let _34: &std::vec::Vec<impl Sized>;
let mut _35: &std::mem::ManuallyDrop<std::vec::Vec<impl Sized>>;
let mut _36: &alloc::raw_vec::RawVec<impl Sized>;
let mut _37: &std::mem::ManuallyDrop<std::vec::Vec<impl Sized>>;
let _3: std::mem::ManuallyDrop<std::vec::Vec<impl Sized>>;
let mut _4: *const std::alloc::Global;
let mut _9: usize;
let mut _11: *mut impl Sized;
let mut _12: *const impl Sized;
let mut _13: usize;
let _29: &std::vec::Vec<impl Sized>;
let mut _30: &std::mem::ManuallyDrop<std::vec::Vec<impl Sized>>;
let mut _31: &alloc::raw_vec::RawVec<impl Sized>;
let mut _32: &std::mem::ManuallyDrop<std::vec::Vec<impl Sized>>;
let _33: &std::vec::Vec<impl Sized>;
let mut _34: &std::mem::ManuallyDrop<std::vec::Vec<impl Sized>>;
let _35: &std::vec::Vec<impl Sized>;
let mut _36: &std::mem::ManuallyDrop<std::vec::Vec<impl Sized>>;
let mut _37: &alloc::raw_vec::RawVec<impl Sized>;
let mut _38: &std::mem::ManuallyDrop<std::vec::Vec<impl Sized>>;
scope 4 {
debug me => _2;
debug me => _3;
scope 5 {
debug alloc => const ManuallyDrop::<std::alloc::Global> {{ value: std::alloc::Global }};
let _6: std::ptr::NonNull<impl Sized>;
debug alloc => const ManuallyDrop::<std::alloc::Global> {{ value: MaybeDangling::<std::alloc::Global>(std::alloc::Global) }};
let _7: std::ptr::NonNull<impl Sized>;
scope 6 {
debug buf => _6;
let _7: *mut impl Sized;
debug buf => _7;
let _8: *mut impl Sized;
scope 7 {
debug begin => _7;
debug begin => _8;
scope 8 {
debug end => _11;
let _19: usize;
debug end => _12;
let _20: usize;
scope 9 {
debug cap => _19;
debug cap => _20;
}
scope 39 (inlined <ManuallyDrop<Vec<impl Sized>> as Deref>::deref) {
debug self => _37;
}
scope 40 (inlined alloc::raw_vec::RawVec::<impl Sized>::capacity) {
debug self => _36;
let mut _38: &alloc::raw_vec::RawVecInner;
scope 41 (inlined std::mem::size_of::<impl Sized>) {
scope 45 (inlined <ManuallyDrop<Vec<impl Sized>> as Deref>::deref) {
debug self => _38;
scope 46 (inlined MaybeDangling::<Vec<impl Sized>>::as_ref) {
}
scope 42 (inlined alloc::raw_vec::RawVecInner::capacity) {
debug self => _38;
}
scope 47 (inlined alloc::raw_vec::RawVec::<impl Sized>::capacity) {
debug self => _37;
let mut _39: &alloc::raw_vec::RawVecInner;
scope 48 (inlined std::mem::size_of::<impl Sized>) {
}
scope 49 (inlined alloc::raw_vec::RawVecInner::capacity) {
debug self => _39;
debug elem_size => const <impl Sized as std::mem::SizedTypeProperties>::SIZE;
let mut _20: core::num::niche_types::UsizeNoHighBit;
scope 43 (inlined core::num::niche_types::UsizeNoHighBit::as_inner) {
debug self => _20;
let mut _21: core::num::niche_types::UsizeNoHighBit;
scope 50 (inlined core::num::niche_types::UsizeNoHighBit::as_inner) {
debug self => _21;
}
}
}
}
scope 25 (inlined <ManuallyDrop<Vec<impl Sized>> as Deref>::deref) {
debug self => _33;
}
scope 26 (inlined Vec::<impl Sized>::len) {
debug self => _32;
let mut _13: bool;
scope 27 {
}
}
scope 28 (inlined std::ptr::mut_ptr::<impl *mut impl Sized>::wrapping_byte_add) {
debug self => _7;
debug count => _12;
let mut _14: *mut u8;
let mut _18: *mut u8;
scope 29 (inlined std::ptr::mut_ptr::<impl *mut impl Sized>::cast::<u8>) {
debug self => _7;
}
scope 30 (inlined std::ptr::mut_ptr::<impl *mut u8>::wrapping_add) {
debug self => _14;
debug count => _12;
let mut _15: isize;
scope 31 (inlined std::ptr::mut_ptr::<impl *mut u8>::wrapping_offset) {
debug self => _14;
debug count => _15;
let mut _16: *const u8;
let mut _17: *const u8;
}
}
scope 32 (inlined std::ptr::mut_ptr::<impl *mut u8>::with_metadata_of::<impl Sized>) {
debug self => _18;
debug meta => _5;
scope 33 (inlined std::ptr::metadata::<impl Sized>) {
debug ptr => _5;
}
scope 34 (inlined std::ptr::from_raw_parts_mut::<impl Sized, ()>) {
}
}
}
scope 35 (inlined <ManuallyDrop<Vec<impl Sized>> as Deref>::deref) {
debug self => _35;
}
scope 36 (inlined Vec::<impl Sized>::len) {
scope 29 (inlined <ManuallyDrop<Vec<impl Sized>> as Deref>::deref) {
debug self => _34;
let mut _9: bool;
scope 37 {
scope 30 (inlined MaybeDangling::<Vec<impl Sized>>::as_ref) {
}
}
scope 38 (inlined #[track_caller] std::ptr::mut_ptr::<impl *mut impl Sized>::add) {
debug self => _7;
debug count => _8;
scope 31 (inlined Vec::<impl Sized>::len) {
debug self => _33;
let mut _14: bool;
scope 32 {
}
}
}
scope 24 (inlined NonNull::<impl Sized>::as_ptr) {
debug self => _6;
}
}
scope 17 (inlined <ManuallyDrop<Vec<impl Sized>> as Deref>::deref) {
debug self => _31;
}
scope 18 (inlined alloc::raw_vec::RawVec::<impl Sized>::non_null) {
debug self => _30;
scope 19 (inlined alloc::raw_vec::RawVecInner::non_null::<impl Sized>) {
let mut _4: std::ptr::NonNull<u8>;
scope 20 (inlined Unique::<u8>::cast::<impl Sized>) {
scope 21 (inlined NonNull::<u8>::cast::<impl Sized>) {
let mut _5: *const impl Sized;
scope 22 (inlined NonNull::<u8>::as_ptr) {
scope 33 (inlined std::ptr::mut_ptr::<impl *mut impl Sized>::wrapping_byte_add) {
debug self => _8;
debug count => _13;
let mut _15: *mut u8;
let mut _19: *mut u8;
scope 34 (inlined std::ptr::mut_ptr::<impl *mut impl Sized>::cast::<u8>) {
debug self => _8;
}
scope 35 (inlined std::ptr::mut_ptr::<impl *mut u8>::wrapping_add) {
debug self => _15;
debug count => _13;
let mut _16: isize;
scope 36 (inlined std::ptr::mut_ptr::<impl *mut u8>::wrapping_offset) {
debug self => _15;
debug count => _16;
let mut _17: *const u8;
let mut _18: *const u8;
}
}
scope 37 (inlined std::ptr::mut_ptr::<impl *mut u8>::with_metadata_of::<impl Sized>) {
debug self => _19;
debug meta => _6;
scope 38 (inlined std::ptr::metadata::<impl Sized>) {
debug ptr => _6;
}
scope 39 (inlined std::ptr::from_raw_parts_mut::<impl Sized, ()>) {
}
}
}
scope 23 (inlined Unique::<impl Sized>::as_non_null_ptr) {
scope 40 (inlined <ManuallyDrop<Vec<impl Sized>> as Deref>::deref) {
debug self => _36;
scope 41 (inlined MaybeDangling::<Vec<impl Sized>>::as_ref) {
}
}
scope 42 (inlined Vec::<impl Sized>::len) {
debug self => _35;
let mut _10: bool;
scope 43 {
}
}
scope 44 (inlined #[track_caller] std::ptr::mut_ptr::<impl *mut impl Sized>::add) {
debug self => _8;
debug count => _9;
}
}
scope 28 (inlined NonNull::<impl Sized>::as_ptr) {
debug self => _7;
}
}
scope 20 (inlined <ManuallyDrop<Vec<impl Sized>> as Deref>::deref) {
debug self => _32;
scope 21 (inlined MaybeDangling::<Vec<impl Sized>>::as_ref) {
}
}
scope 22 (inlined alloc::raw_vec::RawVec::<impl Sized>::non_null) {
debug self => _31;
scope 23 (inlined alloc::raw_vec::RawVecInner::non_null::<impl Sized>) {
let mut _5: std::ptr::NonNull<u8>;
scope 24 (inlined Unique::<u8>::cast::<impl Sized>) {
scope 25 (inlined NonNull::<u8>::cast::<impl Sized>) {
let mut _6: *const impl Sized;
scope 26 (inlined NonNull::<u8>::as_ptr) {
}
}
}
scope 27 (inlined Unique::<impl Sized>::as_non_null_ptr) {
}
}
}
}
scope 11 (inlined <ManuallyDrop<Vec<impl Sized>> as Deref>::deref) {
debug self => _29;
scope 12 (inlined <ManuallyDrop<Vec<impl Sized>> as Deref>::deref) {
debug self => _30;
scope 13 (inlined MaybeDangling::<Vec<impl Sized>>::as_ref) {
}
}
scope 12 (inlined Vec::<impl Sized>::allocator) {
debug self => _28;
scope 13 (inlined alloc::raw_vec::RawVec::<impl Sized>::allocator) {
scope 14 (inlined alloc::raw_vec::RawVecInner::allocator) {
scope 14 (inlined Vec::<impl Sized>::allocator) {
debug self => _29;
scope 15 (inlined alloc::raw_vec::RawVec::<impl Sized>::allocator) {
scope 16 (inlined alloc::raw_vec::RawVecInner::allocator) {
}
}
}
scope 15 (inlined #[track_caller] std::ptr::read::<std::alloc::Global>) {
debug src => _3;
scope 17 (inlined #[track_caller] std::ptr::read::<std::alloc::Global>) {
debug src => _4;
}
scope 16 (inlined ManuallyDrop::<std::alloc::Global>::new) {
scope 18 (inlined ManuallyDrop::<std::alloc::Global>::new) {
debug value => const std::alloc::Global;
scope 19 (inlined MaybeDangling::<std::alloc::Global>::new) {
}
}
}
scope 10 (inlined ManuallyDrop::<Vec<impl Sized>>::new) {
debug value => _1;
let mut _2: std::mem::MaybeDangling<std::vec::Vec<impl Sized>>;
scope 11 (inlined MaybeDangling::<Vec<impl Sized>>::new) {
}
}
}
bb0: {
StorageLive(_21);
StorageLive(_6);
StorageLive(_22);
StorageLive(_7);
StorageLive(_11);
StorageLive(_19);
StorageLive(_8);
StorageLive(_12);
StorageLive(_20);
StorageLive(_6);
StorageLive(_5);
StorageLive(_4);
StorageLive(_17);
StorageLive(_2);
_2 = ManuallyDrop::<Vec<impl Sized>> { value: copy _1 };
StorageLive(_18);
StorageLive(_3);
// DBG: _29 = &_2;
// DBG: _28 = &(_2.0: std::vec::Vec<impl Sized>);
_3 = &raw const ((((_2.0: std::vec::Vec<impl Sized>).0: alloc::raw_vec::RawVec<impl Sized>).0: alloc::raw_vec::RawVecInner).2: std::alloc::Global);
StorageDead(_3);
// DBG: _31 = &_2;
// DBG: _30 = &((_2.0: std::vec::Vec<impl Sized>).0: alloc::raw_vec::RawVec<impl Sized>);
_4 = copy (((((_2.0: std::vec::Vec<impl Sized>).0: alloc::raw_vec::RawVec<impl Sized>).0: alloc::raw_vec::RawVecInner).0: std::ptr::Unique<u8>).0: std::ptr::NonNull<u8>);
_5 = copy _4 as *const impl Sized (Transmute);
_6 = NonNull::<impl Sized> { pointer: copy _5 };
_7 = copy _4 as *mut impl Sized (Transmute);
StorageLive(_2);
_2 = MaybeDangling::<Vec<impl Sized>>(copy _1);
_3 = ManuallyDrop::<Vec<impl Sized>> { value: move _2 };
StorageDead(_2);
StorageLive(_4);
// DBG: _30 = &_3;
// DBG: _29 = &((_3.0: std::mem::MaybeDangling<std::vec::Vec<impl Sized>>).0: std::vec::Vec<impl Sized>);
_4 = &raw const (((((_3.0: std::mem::MaybeDangling<std::vec::Vec<impl Sized>>).0: std::vec::Vec<impl Sized>).0: alloc::raw_vec::RawVec<impl Sized>).0: alloc::raw_vec::RawVecInner).2: std::alloc::Global);
StorageDead(_4);
// DBG: _32 = &_3;
// DBG: _31 = &(((_3.0: std::mem::MaybeDangling<std::vec::Vec<impl Sized>>).0: std::vec::Vec<impl Sized>).0: alloc::raw_vec::RawVec<impl Sized>);
_5 = copy ((((((_3.0: std::mem::MaybeDangling<std::vec::Vec<impl Sized>>).0: std::vec::Vec<impl Sized>).0: alloc::raw_vec::RawVec<impl Sized>).0: alloc::raw_vec::RawVecInner).0: std::ptr::Unique<u8>).0: std::ptr::NonNull<u8>);
_6 = copy _5 as *const impl Sized (Transmute);
_7 = NonNull::<impl Sized> { pointer: copy _6 };
_8 = copy _5 as *mut impl Sized (Transmute);
switchInt(const <impl Sized as std::mem::SizedTypeProperties>::IS_ZST) -> [0: bb1, otherwise: bb2];
}
bb1: {
StorageLive(_10);
StorageLive(_8);
// DBG: _35 = &_2;
// DBG: _34 = &(_2.0: std::vec::Vec<impl Sized>);
_8 = copy ((_2.0: std::vec::Vec<impl Sized>).1: usize);
StorageLive(_11);
StorageLive(_9);
_9 = Le(copy _8, const <impl Sized as std::mem::SizedTypeProperties>::MAX_SLICE_LEN);
assume(move _9);
StorageDead(_9);
_10 = Offset(copy _7, copy _8);
_11 = copy _10 as *const impl Sized (PtrToPtr);
StorageDead(_8);
// DBG: _36 = &_3;
// DBG: _35 = &((_3.0: std::mem::MaybeDangling<std::vec::Vec<impl Sized>>).0: std::vec::Vec<impl Sized>);
_9 = copy (((_3.0: std::mem::MaybeDangling<std::vec::Vec<impl Sized>>).0: std::vec::Vec<impl Sized>).1: usize);
StorageLive(_10);
_10 = Le(copy _9, const <impl Sized as std::mem::SizedTypeProperties>::MAX_SLICE_LEN);
assume(move _10);
StorageDead(_10);
_11 = Offset(copy _8, copy _9);
_12 = copy _11 as *const impl Sized (PtrToPtr);
StorageDead(_9);
StorageDead(_11);
goto -> bb4;
}
bb2: {
StorageLive(_12);
// DBG: _33 = &_2;
// DBG: _32 = &(_2.0: std::vec::Vec<impl Sized>);
_12 = copy ((_2.0: std::vec::Vec<impl Sized>).1: usize);
StorageLive(_13);
_13 = Le(copy _12, const <impl Sized as std::mem::SizedTypeProperties>::MAX_SLICE_LEN);
assume(move _13);
StorageDead(_13);
StorageLive(_18);
// DBG: _34 = &_3;
// DBG: _33 = &((_3.0: std::mem::MaybeDangling<std::vec::Vec<impl Sized>>).0: std::vec::Vec<impl Sized>);
_13 = copy (((_3.0: std::mem::MaybeDangling<std::vec::Vec<impl Sized>>).0: std::vec::Vec<impl Sized>).1: usize);
StorageLive(_14);
_14 = copy _4 as *mut u8 (Transmute);
_14 = Le(copy _13, const <impl Sized as std::mem::SizedTypeProperties>::MAX_SLICE_LEN);
assume(move _14);
StorageDead(_14);
StorageLive(_19);
StorageLive(_15);
_15 = copy _12 as isize (IntToInt);
_15 = copy _5 as *mut u8 (Transmute);
StorageLive(_16);
_16 = copy _4 as *const u8 (Transmute);
_17 = arith_offset::<u8>(move _16, move _15) -> [return: bb3, unwind unreachable];
_16 = copy _13 as isize (IntToInt);
StorageLive(_17);
_17 = copy _5 as *const u8 (Transmute);
_18 = arith_offset::<u8>(move _17, move _16) -> [return: bb3, unwind unreachable];
}
bb3: {
StorageDead(_17);
_19 = copy _18 as *mut u8 (PtrToPtr);
StorageDead(_16);
_18 = copy _17 as *mut u8 (PtrToPtr);
StorageDead(_15);
StorageDead(_14);
StorageDead(_18);
StorageDead(_12);
_11 = copy _17 as *const impl Sized (PtrToPtr);
StorageDead(_19);
StorageDead(_13);
_12 = copy _18 as *const impl Sized (PtrToPtr);
goto -> bb4;
}
bb4: {
// DBG: _37 = &_2;
// DBG: _36 = &((_2.0: std::vec::Vec<impl Sized>).0: alloc::raw_vec::RawVec<impl Sized>);
// DBG: _38 = &(((_2.0: std::vec::Vec<impl Sized>).0: alloc::raw_vec::RawVec<impl Sized>).0: alloc::raw_vec::RawVecInner);
// DBG: _38 = &_3;
// DBG: _37 = &(((_3.0: std::mem::MaybeDangling<std::vec::Vec<impl Sized>>).0: std::vec::Vec<impl Sized>).0: alloc::raw_vec::RawVec<impl Sized>);
// DBG: _39 = &((((_3.0: std::mem::MaybeDangling<std::vec::Vec<impl Sized>>).0: std::vec::Vec<impl Sized>).0: alloc::raw_vec::RawVec<impl Sized>).0: alloc::raw_vec::RawVecInner);
switchInt(const <impl Sized as std::mem::SizedTypeProperties>::SIZE) -> [0: bb5, otherwise: bb6];
}
bb5: {
_19 = const usize::MAX;
_20 = const usize::MAX;
goto -> bb7;
}
bb6: {
StorageLive(_20);
_20 = copy ((((_2.0: std::vec::Vec<impl Sized>).0: alloc::raw_vec::RawVec<impl Sized>).0: alloc::raw_vec::RawVecInner).1: core::num::niche_types::UsizeNoHighBit);
_19 = copy _20 as usize (Transmute);
StorageDead(_20);
StorageLive(_21);
_21 = copy (((((_3.0: std::mem::MaybeDangling<std::vec::Vec<impl Sized>>).0: std::vec::Vec<impl Sized>).0: alloc::raw_vec::RawVec<impl Sized>).0: alloc::raw_vec::RawVecInner).1: core::num::niche_types::UsizeNoHighBit);
_20 = copy _21 as usize (Transmute);
StorageDead(_21);
goto -> bb7;
}
bb7: {
_21 = std::vec::IntoIter::<impl Sized> { buf: copy _6, phantom: const ZeroSized: PhantomData<impl Sized>, cap: move _19, alloc: const ManuallyDrop::<std::alloc::Global> {{ value: std::alloc::Global }}, ptr: copy _6, end: copy _11 };
StorageDead(_2);
StorageDead(_17);
StorageDead(_4);
_22 = std::vec::IntoIter::<impl Sized> { buf: copy _7, phantom: const ZeroSized: PhantomData<impl Sized>, cap: move _20, alloc: const ManuallyDrop::<std::alloc::Global> {{ value: MaybeDangling::<std::alloc::Global>(std::alloc::Global) }}, ptr: copy _7, end: copy _12 };
StorageDead(_3);
StorageDead(_18);
StorageDead(_5);
StorageDead(_19);
StorageDead(_11);
StorageDead(_7);
StorageDead(_6);
StorageLive(_22);
_22 = move _21;
StorageDead(_20);
StorageDead(_12);
StorageDead(_8);
StorageDead(_7);
StorageLive(_23);
_23 = move _22;
goto -> bb8;
}
bb8: {
StorageLive(_24);
_23 = &mut _22;
_24 = <std::vec::IntoIter<impl Sized> as Iterator>::next(move _23) -> [return: bb9, unwind: bb15];
StorageLive(_25);
_24 = &mut _23;
_25 = <std::vec::IntoIter<impl Sized> as Iterator>::next(move _24) -> [return: bb9, unwind: bb15];
}
bb9: {
_25 = discriminant(_24);
switchInt(move _25) -> [0: bb10, 1: bb12, otherwise: bb14];
_26 = discriminant(_25);
switchInt(move _26) -> [0: bb10, 1: bb12, otherwise: bb14];
}
bb10: {
StorageDead(_24);
drop(_22) -> [return: bb11, unwind continue];
StorageDead(_25);
drop(_23) -> [return: bb11, unwind continue];
}
bb11: {
StorageDead(_23);
StorageDead(_22);
StorageDead(_21);
return;
}
bb12: {
_26 = move ((_24 as Some).0: impl Sized);
_27 = opaque::<impl Sized>(move _26) -> [return: bb13, unwind: bb15];
_27 = move ((_25 as Some).0: impl Sized);
_28 = opaque::<impl Sized>(move _27) -> [return: bb13, unwind: bb15];
}
bb13: {
StorageDead(_24);
StorageDead(_25);
goto -> bb8;
}
@ -309,7 +327,7 @@ fn vec_move(_1: Vec<impl Sized>) -> () {
}
bb15 (cleanup): {
drop(_22) -> [return: bb16, unwind terminate(cleanup)];
drop(_23) -> [return: bb16, unwind terminate(cleanup)];
}
bb16 (cleanup): {

View file

@ -7,6 +7,8 @@ print-type-size variant `Returned`: 0 bytes
print-type-size variant `Panicked`: 0 bytes
print-type-size type: `std::mem::ManuallyDrop<{async fn body of calls_fut<{async fn body of big_fut()}>()}>`: 3077 bytes, alignment: 1 bytes
print-type-size field `.value`: 3077 bytes
print-type-size type: `std::mem::MaybeDangling<{async fn body of calls_fut<{async fn body of big_fut()}>()}>`: 3077 bytes, alignment: 1 bytes
print-type-size field `.0`: 3077 bytes
print-type-size type: `std::mem::MaybeUninit<{async fn body of calls_fut<{async fn body of big_fut()}>()}>`: 3077 bytes, alignment: 1 bytes
print-type-size variant `MaybeUninit`: 3077 bytes
print-type-size field `.uninit`: 0 bytes
@ -36,6 +38,8 @@ print-type-size variant `Panicked`: 1025 bytes
print-type-size upvar `.fut`: 1025 bytes
print-type-size type: `std::mem::ManuallyDrop<{async fn body of big_fut()}>`: 1025 bytes, alignment: 1 bytes
print-type-size field `.value`: 1025 bytes
print-type-size type: `std::mem::MaybeDangling<{async fn body of big_fut()}>`: 1025 bytes, alignment: 1 bytes
print-type-size field `.0`: 1025 bytes
print-type-size type: `std::mem::MaybeUninit<{async fn body of big_fut()}>`: 1025 bytes, alignment: 1 bytes
print-type-size variant `MaybeUninit`: 1025 bytes
print-type-size field `.uninit`: 0 bytes
@ -85,6 +89,10 @@ print-type-size type: `std::mem::ManuallyDrop<bool>`: 1 bytes, alignment: 1 byte
print-type-size field `.value`: 1 bytes
print-type-size type: `std::mem::ManuallyDrop<{async fn body of wait()}>`: 1 bytes, alignment: 1 bytes
print-type-size field `.value`: 1 bytes
print-type-size type: `std::mem::MaybeDangling<bool>`: 1 bytes, alignment: 1 bytes
print-type-size field `.0`: 1 bytes
print-type-size type: `std::mem::MaybeDangling<{async fn body of wait()}>`: 1 bytes, alignment: 1 bytes
print-type-size field `.0`: 1 bytes
print-type-size type: `std::mem::MaybeUninit<bool>`: 1 bytes, alignment: 1 bytes
print-type-size variant `MaybeUninit`: 1 bytes
print-type-size field `.uninit`: 0 bytes

View file

@ -7,6 +7,8 @@ print-type-size variant `Returned`: 0 bytes
print-type-size variant `Panicked`: 0 bytes
print-type-size type: `std::mem::ManuallyDrop<{async fn body of a<[u8; 1024]>()}>`: 3075 bytes, alignment: 1 bytes
print-type-size field `.value`: 3075 bytes
print-type-size type: `std::mem::MaybeDangling<{async fn body of a<[u8; 1024]>()}>`: 3075 bytes, alignment: 1 bytes
print-type-size field `.0`: 3075 bytes
print-type-size type: `std::mem::MaybeUninit<{async fn body of a<[u8; 1024]>()}>`: 3075 bytes, alignment: 1 bytes
print-type-size variant `MaybeUninit`: 3075 bytes
print-type-size field `.uninit`: 0 bytes
@ -24,6 +26,8 @@ print-type-size variant `Panicked`: 1024 bytes
print-type-size upvar `.t`: 1024 bytes
print-type-size type: `std::mem::ManuallyDrop<{async fn body of b<[u8; 1024]>()}>`: 2050 bytes, alignment: 1 bytes
print-type-size field `.value`: 2050 bytes
print-type-size type: `std::mem::MaybeDangling<{async fn body of b<[u8; 1024]>()}>`: 2050 bytes, alignment: 1 bytes
print-type-size field `.0`: 2050 bytes
print-type-size type: `std::mem::MaybeUninit<{async fn body of b<[u8; 1024]>()}>`: 2050 bytes, alignment: 1 bytes
print-type-size variant `MaybeUninit`: 2050 bytes
print-type-size field `.uninit`: 0 bytes
@ -41,6 +45,8 @@ print-type-size variant `Panicked`: 1024 bytes
print-type-size upvar `.t`: 1024 bytes
print-type-size type: `std::mem::ManuallyDrop<{async fn body of c<[u8; 1024]>()}>`: 1025 bytes, alignment: 1 bytes
print-type-size field `.value`: 1025 bytes
print-type-size type: `std::mem::MaybeDangling<{async fn body of c<[u8; 1024]>()}>`: 1025 bytes, alignment: 1 bytes
print-type-size field `.0`: 1025 bytes
print-type-size type: `std::mem::MaybeUninit<{async fn body of c<[u8; 1024]>()}>`: 1025 bytes, alignment: 1 bytes
print-type-size variant `MaybeUninit`: 1025 bytes
print-type-size field `.uninit`: 0 bytes

View file

@ -12,6 +12,8 @@ print-type-size variant `Panicked`: 8192 bytes
print-type-size upvar `.arg`: 8192 bytes
print-type-size type: `std::mem::ManuallyDrop<[u8; 8192]>`: 8192 bytes, alignment: 1 bytes
print-type-size field `.value`: 8192 bytes
print-type-size type: `std::mem::MaybeDangling<[u8; 8192]>`: 8192 bytes, alignment: 1 bytes
print-type-size field `.0`: 8192 bytes
print-type-size type: `std::mem::MaybeUninit<[u8; 8192]>`: 8192 bytes, alignment: 1 bytes
print-type-size variant `MaybeUninit`: 8192 bytes
print-type-size field `.uninit`: 0 bytes
@ -47,6 +49,8 @@ print-type-size type: `std::ptr::NonNull<std::ptr::metadata::VTable>`: 8 bytes,
print-type-size field `.pointer`: 8 bytes
print-type-size type: `std::mem::ManuallyDrop<{async fn body of wait()}>`: 1 bytes, alignment: 1 bytes
print-type-size field `.value`: 1 bytes
print-type-size type: `std::mem::MaybeDangling<{async fn body of wait()}>`: 1 bytes, alignment: 1 bytes
print-type-size field `.0`: 1 bytes
print-type-size type: `std::mem::MaybeUninit<{async fn body of wait()}>`: 1 bytes, alignment: 1 bytes
print-type-size variant `MaybeUninit`: 1 bytes
print-type-size field `.uninit`: 0 bytes

View file

@ -11,6 +11,8 @@ print-type-size variant `Returned`: 0 bytes
print-type-size variant `Panicked`: 0 bytes
print-type-size type: `std::mem::ManuallyDrop<i32>`: 4 bytes, alignment: 4 bytes
print-type-size field `.value`: 4 bytes
print-type-size type: `std::mem::MaybeDangling<i32>`: 4 bytes, alignment: 4 bytes
print-type-size field `.0`: 4 bytes
print-type-size type: `std::mem::MaybeUninit<i32>`: 4 bytes, alignment: 4 bytes
print-type-size variant `MaybeUninit`: 4 bytes
print-type-size field `.uninit`: 0 bytes

View file

@ -68,7 +68,7 @@ body:
)
else_block: None
lint_level: Explicit(HirId(DefId(offset_of::concrete).10))
span: $DIR/offset_of.rs:37:5: 1433:57 (#0)
span: $DIR/offset_of.rs:37:5: 1437:57 (#0)
}
}
Stmt {
@ -117,7 +117,7 @@ body:
)
else_block: None
lint_level: Explicit(HirId(DefId(offset_of::concrete).20))
span: $DIR/offset_of.rs:38:5: 1433:57 (#0)
span: $DIR/offset_of.rs:38:5: 1437:57 (#0)
}
}
Stmt {
@ -166,7 +166,7 @@ body:
)
else_block: None
lint_level: Explicit(HirId(DefId(offset_of::concrete).30))
span: $DIR/offset_of.rs:39:5: 1433:57 (#0)
span: $DIR/offset_of.rs:39:5: 1437:57 (#0)
}
}
Stmt {
@ -215,7 +215,7 @@ body:
)
else_block: None
lint_level: Explicit(HirId(DefId(offset_of::concrete).40))
span: $DIR/offset_of.rs:40:5: 1433:57 (#0)
span: $DIR/offset_of.rs:40:5: 1437:57 (#0)
}
}
Stmt {
@ -264,7 +264,7 @@ body:
)
else_block: None
lint_level: Explicit(HirId(DefId(offset_of::concrete).50))
span: $DIR/offset_of.rs:41:5: 1433:57 (#0)
span: $DIR/offset_of.rs:41:5: 1437:57 (#0)
}
}
]
@ -864,7 +864,7 @@ body:
)
else_block: None
lint_level: Explicit(HirId(DefId(offset_of::generic).12))
span: $DIR/offset_of.rs:45:5: 1433:57 (#0)
span: $DIR/offset_of.rs:45:5: 1437:57 (#0)
}
}
Stmt {
@ -913,7 +913,7 @@ body:
)
else_block: None
lint_level: Explicit(HirId(DefId(offset_of::generic).24))
span: $DIR/offset_of.rs:46:5: 1433:57 (#0)
span: $DIR/offset_of.rs:46:5: 1437:57 (#0)
}
}
Stmt {
@ -962,7 +962,7 @@ body:
)
else_block: None
lint_level: Explicit(HirId(DefId(offset_of::generic).36))
span: $DIR/offset_of.rs:47:5: 1433:57 (#0)
span: $DIR/offset_of.rs:47:5: 1437:57 (#0)
}
}
Stmt {
@ -1011,7 +1011,7 @@ body:
)
else_block: None
lint_level: Explicit(HirId(DefId(offset_of::generic).48))
span: $DIR/offset_of.rs:48:5: 1433:57 (#0)
span: $DIR/offset_of.rs:48:5: 1437:57 (#0)
}
}
]