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Rename pointer field on Pin

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The internal, unstable field of `Pin` can conflict with fields from the
inner type accessed via the `Deref` impl. Rename it from `pointer` to
`__pointer`, to make it less likely to conflict with anything else.
This commit is contained in:
LegionMammal978 2024-01-16 14:58:42 -05:00
parent e64f8495e7
commit bc3fb5245a
8 changed files with 35 additions and 29 deletions
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2
compiler/rustc_hir_typeck/src/fn_ctxt/suggestions.rs
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@ -2038,7 +2038,7 @@ pub(crate) fn suggest_compatible_variants(
let field_is_local = sole_field.did.is_local();
let field_is_accessible =
sole_field.vis.is_accessible_from(expr.hir_id.owner.def_id, self.tcx)
// Skip suggestions for unstable public fields (for example `Pin::pointer`)
// Skip suggestions for unstable public fields (for example `Pin::__pointer`)
&& matches!(self.tcx.eval_stability(sole_field.did, None, expr.span, None), EvalResult::Allow | EvalResult::Unmarked);
if !field_is_local && !field_is_accessible {

46
library/core/src/pin.rs
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@ -1092,14 +1092,20 @@ pub struct Pin<Ptr> {
// - deter downstream users from accessing it (which would be unsound!),
// - let the `pin!` macro access it (such a macro requires using struct
// literal syntax in order to benefit from lifetime extension).
// Long-term, `unsafe` fields or macro hygiene are expected to offer more robust alternatives.
//
// However, if the `Deref` impl exposes a field with the same name as this
// field, then the two will collide, resulting in a confusing error when the
// user attempts to access the field through a `Pin<Ptr>`. Therefore, the
// name `__pointer` is designed to be unlikely to collide with any other
// field. Long-term, macro hygiene is expected to offer a more robust
// alternative, alongside `unsafe` fields.
#[unstable(feature = "unsafe_pin_internals", issue = "none")]
#[doc(hidden)]
pub pointer: Ptr,
pub __pointer: Ptr,
}
// The following implementations aren't derived in order to avoid soundness
// issues. `&self.pointer` should not be accessible to untrusted trait
// issues. `&self.__pointer` should not be accessible to untrusted trait
// implementations.
//
// See <https://internals.rust-lang.org/t/unsoundness-in-pin/11311/73> for more details.
@ -1212,7 +1218,7 @@ pub const fn new(pointer: Ptr) -> Pin<Ptr> {
#[rustc_const_unstable(feature = "const_pin", issue = "76654")]
#[stable(feature = "pin_into_inner", since = "1.39.0")]
pub const fn into_inner(pin: Pin<Ptr>) -> Ptr {
pin.pointer
pin.__pointer
}
}
@ -1349,7 +1355,7 @@ impl<Ptr: Deref> Pin<Ptr> {
#[rustc_const_unstable(feature = "const_pin", issue = "76654")]
#[stable(feature = "pin", since = "1.33.0")]
pub const unsafe fn new_unchecked(pointer: Ptr) -> Pin<Ptr> {
Pin { pointer }
Pin { __pointer: pointer }
}
/// Gets a shared reference to the pinned value this [`Pin`] points to.
@ -1363,7 +1369,7 @@ impl<Ptr: Deref> Pin<Ptr> {
#[inline(always)]
pub fn as_ref(&self) -> Pin<&Ptr::Target> {
// SAFETY: see documentation on this function
unsafe { Pin::new_unchecked(&*self.pointer) }
unsafe { Pin::new_unchecked(&*self.__pointer) }
}
/// Unwraps this `Pin<Ptr>`, returning the underlying `Ptr`.
@ -1388,7 +1394,7 @@ pub fn as_ref(&self) -> Pin<&Ptr::Target> {
#[rustc_const_unstable(feature = "const_pin", issue = "76654")]
#[stable(feature = "pin_into_inner", since = "1.39.0")]
pub const unsafe fn into_inner_unchecked(pin: Pin<Ptr>) -> Ptr {
pin.pointer
pin.__pointer
}
}
@ -1426,7 +1432,7 @@ impl<Ptr: DerefMut> Pin<Ptr> {
#[inline(always)]
pub fn as_mut(&mut self) -> Pin<&mut Ptr::Target> {
// SAFETY: see documentation on this function
unsafe { Pin::new_unchecked(&mut *self.pointer) }
unsafe { Pin::new_unchecked(&mut *self.__pointer) }
}
/// Assigns a new value to the memory location pointed to by the `Pin<Ptr>`.
@ -1455,7 +1461,7 @@ pub fn set(&mut self, value: Ptr::Target)
where
Ptr::Target: Sized,
{
*(self.pointer) = value;
*(self.__pointer) = value;
}
}
@ -1481,7 +1487,7 @@ pub unsafe fn map_unchecked<U, F>(self, func: F) -> Pin<&'a U>
U: ?Sized,
F: FnOnce(&T) -> &U,
{
let pointer = &*self.pointer;
let pointer = &*self.__pointer;
let new_pointer = func(pointer);
// SAFETY: the safety contract for `new_unchecked` must be
@ -1511,7 +1517,7 @@ pub unsafe fn map_unchecked<U, F>(self, func: F) -> Pin<&'a U>
#[rustc_const_unstable(feature = "const_pin", issue = "76654")]
#[stable(feature = "pin", since = "1.33.0")]
pub const fn get_ref(self) -> &'a T {
self.pointer
self.__pointer
}
}
@ -1522,7 +1528,7 @@ impl<'a, T: ?Sized> Pin<&'a mut T> {
#[rustc_const_unstable(feature = "const_pin", issue = "76654")]
#[stable(feature = "pin", since = "1.33.0")]
pub const fn into_ref(self) -> Pin<&'a T> {
Pin { pointer: self.pointer }
Pin { __pointer: self.__pointer }
}
/// Gets a mutable reference to the data inside of this `Pin`.
@ -1542,7 +1548,7 @@ pub const fn get_mut(self) -> &'a mut T
where
T: Unpin,
{
self.pointer
self.__pointer
}
/// Gets a mutable reference to the data inside of this `Pin`.
@ -1560,7 +1566,7 @@ pub const fn get_mut(self) -> &'a mut T
#[stable(feature = "pin", since = "1.33.0")]
#[rustc_const_unstable(feature = "const_pin", issue = "76654")]
pub const unsafe fn get_unchecked_mut(self) -> &'a mut T {
self.pointer
self.__pointer
}
/// Construct a new pin by mapping the interior value.
@ -1684,21 +1690,21 @@ impl<Ptr: Receiver> Receiver for Pin<Ptr> {}
#[stable(feature = "pin", since = "1.33.0")]
impl<Ptr: fmt::Debug> fmt::Debug for Pin<Ptr> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Debug::fmt(&self.pointer, f)
fmt::Debug::fmt(&self.__pointer, f)
}
}
#[stable(feature = "pin", since = "1.33.0")]
impl<Ptr: fmt::Display> fmt::Display for Pin<Ptr> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Display::fmt(&self.pointer, f)
fmt::Display::fmt(&self.__pointer, f)
}
}
#[stable(feature = "pin", since = "1.33.0")]
impl<Ptr: fmt::Pointer> fmt::Pointer for Pin<Ptr> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
fmt::Pointer::fmt(&self.pointer, f)
fmt::Pointer::fmt(&self.__pointer, f)
}
}
@ -1941,16 +1947,16 @@ impl<Ptr, U> DispatchFromDyn<Pin<U>> for Pin<Ptr> where Ptr: DispatchFromDyn<U>
// instead, dropped _at the end of the enscoping block_.
// For instance,
// ```rust
// let p = Pin { pointer: &mut <temporary> };
// let p = Pin { __pointer: &mut <temporary> };
// ```
// becomes:
// ```rust
// let mut anon = <temporary>;
// let p = Pin { pointer: &mut anon };
// let p = Pin { __pointer: &mut anon };
// ```
// which is *exactly* what we want.
//
// See https://doc.rust-lang.org/1.58.1/reference/destructors.html#temporary-lifetime-extension
// for more info.
$crate::pin::Pin::<&mut _> { pointer: &mut { $value } }
$crate::pin::Pin::<&mut _> { __pointer: &mut { $value } }
}

4
src/etc/natvis/libcore.natvis
View File

@ -99,9 +99,9 @@
</Type>
<Type Name="core::pin::Pin&lt;*&gt;">
<DisplayString>Pin({(void*)pointer}: {pointer})</DisplayString>
<DisplayString>Pin({(void*)__pointer}: {__pointer})</DisplayString>
<Expand>
<ExpandedItem>pointer</ExpandedItem>
<ExpandedItem>__pointer</ExpandedItem>
</Expand>
</Type>

2
tests/mir-opt/inline/inline_coroutine.main.Inline.panic-abort.diff
View File

@ -36,7 +36,7 @@
- _4 = g() -> [return: bb1, unwind unreachable];
+ _4 = {coroutine@$DIR/inline_coroutine.rs:19:5: 19:8 (#0)};
+ _3 = &mut _4;
+ _2 = Pin::<&mut {coroutine@$DIR/inline_coroutine.rs:19:5: 19:8}> { pointer: _3 };
+ _2 = Pin::<&mut {coroutine@$DIR/inline_coroutine.rs:19:5: 19:8}> { __pointer: _3 };
+ StorageDead(_3);
+ StorageLive(_5);
+ _5 = const false;

2
tests/mir-opt/inline/inline_coroutine.main.Inline.panic-unwind.diff
View File

@ -36,7 +36,7 @@
- _4 = g() -> [return: bb1, unwind continue];
+ _4 = {coroutine@$DIR/inline_coroutine.rs:19:5: 19:8 (#0)};
+ _3 = &mut _4;
+ _2 = Pin::<&mut {coroutine@$DIR/inline_coroutine.rs:19:5: 19:8}> { pointer: _3 };
+ _2 = Pin::<&mut {coroutine@$DIR/inline_coroutine.rs:19:5: 19:8}> { __pointer: _3 };
+ StorageDead(_3);
+ StorageLive(_5);
+ _5 = const false;

2
tests/ui/feature-gates/feature-gate-unsafe_pin_internals.rs
View File

@ -7,7 +7,7 @@
/// The `unsafe_pin_internals` is indeed unsound.
fn non_unsafe_pin_new_unchecked<T>(pointer: &mut T) -> Pin<&mut T> {
Pin { pointer }
Pin { __pointer: pointer }
}
fn main() {

2
tests/ui/pin-macro/cant_access_internals.rs
View File

@ -8,5 +8,5 @@
fn main() {
let mut phantom_pinned = pin!(PhantomPinned);
mem::take(phantom_pinned.pointer); //~ ERROR use of unstable library feature 'unsafe_pin_internals'
mem::take(phantom_pinned.__pointer); //~ ERROR use of unstable library feature 'unsafe_pin_internals'
}

4
tests/ui/pin-macro/cant_access_internals.stderr
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@ -1,8 +1,8 @@
error[E0658]: use of unstable library feature 'unsafe_pin_internals'
--> $DIR/cant_access_internals.rs:11:15
|
LL | mem::take(phantom_pinned.pointer);
| ^^^^^^^^^^^^^^^^^^^^^^
LL | mem::take(phantom_pinned.__pointer);
| ^^^^^^^^^^^^^^^^^^^^^^^^
|
= help: add `#![feature(unsafe_pin_internals)]` to the crate attributes to enable
= note: this compiler was built on YYYY-MM-DD; consider upgrading it if it is out of date