From 1dd77cd24acd5a960c4ddaa7a368d1518a995407 Mon Sep 17 00:00:00 2001
From: Mara Bos <m-ou.se@m-ou.se>
Date: Thu, 27 Mar 2025 18:30:51 +0100
Subject: [PATCH 1/4] Implement `pin!()` using `super let`.
---
compiler/rustc_span/src/symbol.rs | 1 -
library/core/src/pin.rs | 137 +++++-------------
library/coretests/tests/pin_macro.rs | 1 +
.../feature-gate-unsafe_pin_internals.rs | 16 --
.../feature-gate-unsafe_pin_internals.stderr | 15 --
tests/ui/pin-macro/cant_access_internals.rs | 12 --
.../ui/pin-macro/cant_access_internals.stderr | 12 --
7 files changed, 36 insertions(+), 158 deletions(-)
delete mode 100644 tests/ui/feature-gates/feature-gate-unsafe_pin_internals.rs
delete mode 100644 tests/ui/feature-gates/feature-gate-unsafe_pin_internals.stderr
delete mode 100644 tests/ui/pin-macro/cant_access_internals.rs
delete mode 100644 tests/ui/pin-macro/cant_access_internals.stderr
diff --git a/compiler/rustc_span/src/symbol.rs b/compiler/rustc_span/src/symbol.rs
index d1f3eb16e4e4a..4f6e64dc12710 100644
--- a/compiler/rustc_span/src/symbol.rs
+++ b/compiler/rustc_span/src/symbol.rs
@@ -2215,7 +2215,6 @@ symbols! {
unsafe_extern_blocks,
unsafe_fields,
unsafe_no_drop_flag,
- unsafe_pin_internals,
unsafe_pinned,
unsafe_unpin,
unsize,
diff --git a/library/core/src/pin.rs b/library/core/src/pin.rs
index 48ed5ae451e40..9e6acf04bf722 100644
--- a/library/core/src/pin.rs
+++ b/library/core/src/pin.rs
@@ -1092,24 +1092,15 @@ pub use self::unsafe_pinned::UnsafePinned;
#[rustc_pub_transparent]
#[derive(Copy, Clone)]
pub struct Pin<Ptr> {
- // FIXME(#93176): this field is made `#[unstable] #[doc(hidden)] pub` to:
- // - 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).
- //
- // 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,
+ /// Only public for bootstrap.
+ #[cfg(bootstrap)]
+ pub pointer: Ptr,
+ #[cfg(not(bootstrap))]
+ 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.
@@ -1223,7 +1214,7 @@ impl<Ptr: Deref<Target: Unpin>> Pin<Ptr> {
#[rustc_const_stable(feature = "const_pin", since = "1.84.0")]
#[stable(feature = "pin_into_inner", since = "1.39.0")]
pub const fn into_inner(pin: Pin<Ptr>) -> Ptr {
- pin.__pointer
+ pin.pointer
}
}
@@ -1360,7 +1351,7 @@ impl<Ptr: Deref> Pin<Ptr> {
#[rustc_const_stable(feature = "const_pin", since = "1.84.0")]
#[stable(feature = "pin", since = "1.33.0")]
pub const unsafe fn new_unchecked(pointer: Ptr) -> Pin<Ptr> {
- Pin { __pointer: pointer }
+ Pin { pointer }
}
/// Gets a shared reference to the pinned value this [`Pin`] points to.
@@ -1374,7 +1365,7 @@ 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) }
}
}
@@ -1418,7 +1409,7 @@ 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) }
}
/// Gets `Pin<&mut T>` to the underlying pinned value from this nested `Pin`-pointer.
@@ -1485,7 +1476,7 @@ impl<Ptr: DerefMut> Pin<Ptr> {
where
Ptr::Target: Sized,
{
- *(self.__pointer) = value;
+ *(self.pointer) = value;
}
}
@@ -1513,7 +1504,7 @@ impl<Ptr: Deref> Pin<Ptr> {
#[rustc_const_stable(feature = "const_pin", since = "1.84.0")]
#[stable(feature = "pin_into_inner", since = "1.39.0")]
pub const unsafe fn into_inner_unchecked(pin: Pin<Ptr>) -> Ptr {
- pin.__pointer
+ pin.pointer
}
}
@@ -1539,7 +1530,7 @@ impl<'a, T: ?Sized> Pin<&'a T> {
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
@@ -1569,7 +1560,7 @@ impl<'a, T: ?Sized> Pin<&'a T> {
#[rustc_const_stable(feature = "const_pin", since = "1.84.0")]
#[stable(feature = "pin", since = "1.33.0")]
pub const fn get_ref(self) -> &'a T {
- self.__pointer
+ self.pointer
}
}
@@ -1580,7 +1571,7 @@ impl<'a, T: ?Sized> Pin<&'a mut T> {
#[rustc_const_stable(feature = "const_pin", since = "1.84.0")]
#[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`.
@@ -1600,7 +1591,7 @@ impl<'a, T: ?Sized> Pin<&'a mut T> {
where
T: Unpin,
{
- self.__pointer
+ self.pointer
}
/// Gets a mutable reference to the data inside of this `Pin`.
@@ -1618,7 +1609,7 @@ impl<'a, T: ?Sized> Pin<&'a mut T> {
#[stable(feature = "pin", since = "1.33.0")]
#[rustc_const_stable(feature = "const_pin", since = "1.84.0")]
pub const unsafe fn get_unchecked_mut(self) -> &'a mut T {
- self.__pointer
+ self.pointer
}
/// Constructs a new pin by mapping the interior value.
@@ -1705,21 +1696,21 @@ impl<Ptr: LegacyReceiver> LegacyReceiver 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)
}
}
@@ -1945,80 +1936,22 @@ unsafe impl<T: ?Sized> PinCoerceUnsized for *mut T {}
/// constructor.
///
/// [`Box::pin`]: ../../std/boxed/struct.Box.html#method.pin
+#[cfg(not(bootstrap))]
#[stable(feature = "pin_macro", since = "1.68.0")]
#[rustc_macro_transparency = "semitransparent"]
-#[allow_internal_unstable(unsafe_pin_internals)]
-#[rustc_macro_edition_2021]
+#[allow_internal_unstable(super_let)]
pub macro pin($value:expr $(,)?) {
- // This is `Pin::new_unchecked(&mut { $value })`, so, for starters, let's
- // review such a hypothetical macro (that any user-code could define):
- //
- // ```rust
- // macro_rules! pin {( $value:expr ) => (
- // match &mut { $value } { at_value => unsafe { // Do not wrap `$value` in an `unsafe` block.
- // $crate::pin::Pin::<&mut _>::new_unchecked(at_value)
- // }}
- // )}
- // ```
- //
- // Safety:
- // - `type P = &mut _`. There are thus no pathological `Deref{,Mut}` impls
- // that would break `Pin`'s invariants.
- // - `{ $value }` is braced, making it a _block expression_, thus **moving**
- // the given `$value`, and making it _become an **anonymous** temporary_.
- // By virtue of being anonymous, it can no longer be accessed, thus
- // preventing any attempts to `mem::replace` it or `mem::forget` it, _etc._
- //
- // This gives us a `pin!` definition that is sound, and which works, but only
- // in certain scenarios:
- // - If the `pin!(value)` expression is _directly_ fed to a function call:
- // `let poll = pin!(fut).poll(cx);`
- // - If the `pin!(value)` expression is part of a scrutinee:
- // ```rust
- // match pin!(fut) { pinned_fut => {
- // pinned_fut.as_mut().poll(...);
- // pinned_fut.as_mut().poll(...);
- // }} // <- `fut` is dropped here.
- // ```
- // Alas, it doesn't work for the more straight-forward use-case: `let` bindings.
- // ```rust
- // let pinned_fut = pin!(fut); // <- temporary value is freed at the end of this statement
- // pinned_fut.poll(...) // error[E0716]: temporary value dropped while borrowed
- // // note: consider using a `let` binding to create a longer lived value
- // ```
- // - Issues such as this one are the ones motivating https://github.com/rust-lang/rfcs/pull/66
- //
- // This makes such a macro incredibly unergonomic in practice, and the reason most macros
- // out there had to take the path of being a statement/binding macro (_e.g._, `pin!(future);`)
- // instead of featuring the more intuitive ergonomics of an expression macro.
- //
- // Luckily, there is a way to avoid the problem. Indeed, the problem stems from the fact that a
- // temporary is dropped at the end of its enclosing statement when it is part of the parameters
- // given to function call, which has precisely been the case with our `Pin::new_unchecked()`!
- // For instance,
- // ```rust
- // let p = Pin::new_unchecked(&mut <temporary>);
- // ```
- // becomes:
- // ```rust
- // let p = { let mut anon = <temporary>; &mut anon };
- // ```
- //
- // However, when using a literal braced struct to construct the value, references to temporaries
- // can then be taken. This makes Rust change the lifespan of such temporaries so that they are,
- // instead, dropped _at the end of the enscoping block_.
- // For instance,
- // ```rust
- // let p = Pin { __pointer: &mut <temporary> };
- // ```
- // becomes:
- // ```rust
- // let mut anon = <temporary>;
- // 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 } }
+ {
+ super let mut pinned = $value;
+ // SAFETY: The value is pinned: it is the local above which cannot be named outside this macro.
+ unsafe { $crate::pin::Pin::new_unchecked(&mut pinned) }
+ }
+}
+
+/// Only for bootstrap.
+#[cfg(bootstrap)]
+#[stable(feature = "pin_macro", since = "1.68.0")]
+#[rustc_macro_transparency = "semitransparent"]
+pub macro pin($value:expr $(,)?) {
+ $crate::pin::Pin::<&mut _> { pointer: &mut { $value } }
}
diff --git a/library/coretests/tests/pin_macro.rs b/library/coretests/tests/pin_macro.rs
index bfbfa8d280fa1..3174c91a6498b 100644
--- a/library/coretests/tests/pin_macro.rs
+++ b/library/coretests/tests/pin_macro.rs
@@ -38,6 +38,7 @@ fn rust_2024_expr() {
}
#[test]
+#[cfg(not(bootstrap))]
fn temp_lifetime() {
// Check that temporary lifetimes work as in Rust 2021.
// Regression test for https://github.com/rust-lang/rust/issues/138596
diff --git a/tests/ui/feature-gates/feature-gate-unsafe_pin_internals.rs b/tests/ui/feature-gates/feature-gate-unsafe_pin_internals.rs
deleted file mode 100644
index deb5a2f691b8e..0000000000000
--- a/tests/ui/feature-gates/feature-gate-unsafe_pin_internals.rs
+++ /dev/null
@@ -1,16 +0,0 @@
-//@ edition:2018
-#![forbid(internal_features, unsafe_code)]
-#![feature(unsafe_pin_internals)]
-//~^ ERROR the feature `unsafe_pin_internals` is internal to the compiler or standard library
-
-use core::{marker::PhantomPinned, pin::Pin};
-
-/// The `unsafe_pin_internals` is indeed unsound.
-fn non_unsafe_pin_new_unchecked<T>(pointer: &mut T) -> Pin<&mut T> {
- Pin { __pointer: pointer }
-}
-
-fn main() {
- let mut self_referential = PhantomPinned;
- let _: Pin<&mut PhantomPinned> = non_unsafe_pin_new_unchecked(&mut self_referential);
-}
diff --git a/tests/ui/feature-gates/feature-gate-unsafe_pin_internals.stderr b/tests/ui/feature-gates/feature-gate-unsafe_pin_internals.stderr
deleted file mode 100644
index fc9bcd90e52ee..0000000000000
--- a/tests/ui/feature-gates/feature-gate-unsafe_pin_internals.stderr
+++ /dev/null
@@ -1,15 +0,0 @@
-error: the feature `unsafe_pin_internals` is internal to the compiler or standard library
- --> $DIR/feature-gate-unsafe_pin_internals.rs:3:12
- |
-LL | #![feature(unsafe_pin_internals)]
- | ^^^^^^^^^^^^^^^^^^^^
- |
- = note: using it is strongly discouraged
-note: the lint level is defined here
- --> $DIR/feature-gate-unsafe_pin_internals.rs:2:11
- |
-LL | #![forbid(internal_features, unsafe_code)]
- | ^^^^^^^^^^^^^^^^^
-
-error: aborting due to 1 previous error
-
diff --git a/tests/ui/pin-macro/cant_access_internals.rs b/tests/ui/pin-macro/cant_access_internals.rs
deleted file mode 100644
index 36a47d0fdf937..0000000000000
--- a/tests/ui/pin-macro/cant_access_internals.rs
+++ /dev/null
@@ -1,12 +0,0 @@
-//@ edition:2018
-
-use core::{
- marker::PhantomPinned,
- mem,
- pin::{pin, Pin},
-};
-
-fn main() {
- let mut phantom_pinned = pin!(PhantomPinned);
- mem::take(phantom_pinned.__pointer); //~ ERROR use of unstable library feature `unsafe_pin_internals`
-}
diff --git a/tests/ui/pin-macro/cant_access_internals.stderr b/tests/ui/pin-macro/cant_access_internals.stderr
deleted file mode 100644
index 8ad897bbbb951..0000000000000
--- a/tests/ui/pin-macro/cant_access_internals.stderr
+++ /dev/null
@@ -1,12 +0,0 @@
-error[E0658]: use of unstable library feature `unsafe_pin_internals`
- --> $DIR/cant_access_internals.rs:11:15
- |
-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
-
-error: aborting due to 1 previous error
-
-For more information about this error, try `rustc --explain E0658`.
From d20b270b4e431a010e9149a64e816a9ff2b3dec9 Mon Sep 17 00:00:00 2001
From: Mara Bos <m-ou.se@m-ou.se>
Date: Fri, 28 Mar 2025 09:41:31 +0100
Subject: [PATCH 2/4] Don't name macro internals in "does not live long enough"
errors.
---
.../src/diagnostics/conflict_errors.rs | 16 +++++++++++-----
.../src/diagnostics/explain_borrow.rs | 4 +++-
2 files changed, 14 insertions(+), 6 deletions(-)
diff --git a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
index 8a8ecc3b96e3c..2853ae0239e77 100644
--- a/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/conflict_errors.rs
@@ -2959,21 +2959,27 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
}
}
- let mut err = self.path_does_not_live_long_enough(borrow_span, &format!("`{name}`"));
+ let name = if borrow_span.in_external_macro(self.infcx.tcx.sess.source_map()) {
+ // Don't name local variables in external macros.
+ "value".to_string()
+ } else {
+ format!("`{name}`")
+ };
+
+ let mut err = self.path_does_not_live_long_enough(borrow_span, &name);
if let Some(annotation) = self.annotate_argument_and_return_for_borrow(borrow) {
let region_name = annotation.emit(self, &mut err);
err.span_label(
borrow_span,
- format!("`{name}` would have to be valid for `{region_name}`..."),
+ format!("{name} would have to be valid for `{region_name}`..."),
);
err.span_label(
drop_span,
format!(
- "...but `{}` will be dropped here, when the {} returns",
- name,
+ "...but {name} will be dropped here, when the {} returns",
self.infcx
.tcx
.opt_item_name(self.mir_def_id().to_def_id())
@@ -3011,7 +3017,7 @@ impl<'infcx, 'tcx> MirBorrowckCtxt<'_, 'infcx, 'tcx> {
}
} else {
err.span_label(borrow_span, "borrowed value does not live long enough");
- err.span_label(drop_span, format!("`{name}` dropped here while still borrowed"));
+ err.span_label(drop_span, format!("{name} dropped here while still borrowed"));
borrow_spans.args_subdiag(&mut err, |args_span| {
crate::session_diagnostics::CaptureArgLabel::Capture {
diff --git a/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs b/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
index f77dda0d386aa..a845431facac1 100644
--- a/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
+++ b/compiler/rustc_borrowck/src/diagnostics/explain_borrow.rs
@@ -95,7 +95,9 @@ impl<'tcx> BorrowExplanation<'tcx> {
&& let hir::def::Res::Local(hir_id) = p.res
&& let hir::Node::Pat(pat) = tcx.hir_node(hir_id)
{
- err.span_label(pat.span, format!("binding `{ident}` declared here"));
+ if !ident.span.in_external_macro(tcx.sess.source_map()) {
+ err.span_label(pat.span, format!("binding `{ident}` declared here"));
+ }
}
}
}
From 1ca930098911d5059b810b473941a94185cb29ff Mon Sep 17 00:00:00 2001
From: Mara Bos <m-ou.se@m-ou.se>
Date: Thu, 27 Mar 2025 18:32:53 +0100
Subject: [PATCH 3/4] Update tests.
---
...ine_coroutine.main.Inline.panic-abort.diff | 2 +-
...ne_coroutine.main.Inline.panic-unwind.diff | 2 +-
...y.run2-{closure#0}.Inline.panic-abort.diff | 6 +++---
....run2-{closure#0}.Inline.panic-unwind.diff | 6 +++---
tests/pretty/postfix-yield.rs | 3 ++-
.../pin-ergonomics/reborrow-once.stderr | 2 +-
tests/ui/coroutine/postfix-yield.rs | 2 +-
.../lifetime_errors_on_promotion_misusage.rs | 4 ++--
...fetime_errors_on_promotion_misusage.stderr | 20 +++++++------------
tests/ui/pin-macro/pin_move.stderr | 5 +++++
10 files changed, 26 insertions(+), 26 deletions(-)
diff --git a/tests/mir-opt/inline/inline_coroutine.main.Inline.panic-abort.diff b/tests/mir-opt/inline/inline_coroutine.main.Inline.panic-abort.diff
index 56d4d50e967e2..151580da19e09 100644
--- a/tests/mir-opt/inline/inline_coroutine.main.Inline.panic-abort.diff
+++ b/tests/mir-opt/inline/inline_coroutine.main.Inline.panic-abort.diff
@@ -33,7 +33,7 @@
- _4 = g() -> [return: bb1, unwind unreachable];
+ _4 = {coroutine@$DIR/inline_coroutine.rs:20:5: 20:8 (#0)};
+ _3 = &mut _4;
-+ _2 = Pin::<&mut {coroutine@$DIR/inline_coroutine.rs:20:5: 20:8}> { __pointer: copy _3 };
++ _2 = Pin::<&mut {coroutine@$DIR/inline_coroutine.rs:20:5: 20:8}> { pointer: copy _3 };
+ StorageDead(_3);
+ StorageLive(_5);
+ _5 = const false;
diff --git a/tests/mir-opt/inline/inline_coroutine.main.Inline.panic-unwind.diff b/tests/mir-opt/inline/inline_coroutine.main.Inline.panic-unwind.diff
index 751916a00f14d..6196fc0d0c6bf 100644
--- a/tests/mir-opt/inline/inline_coroutine.main.Inline.panic-unwind.diff
+++ b/tests/mir-opt/inline/inline_coroutine.main.Inline.panic-unwind.diff
@@ -33,7 +33,7 @@
- _4 = g() -> [return: bb1, unwind continue];
+ _4 = {coroutine@$DIR/inline_coroutine.rs:20:5: 20:8 (#0)};
+ _3 = &mut _4;
-+ _2 = Pin::<&mut {coroutine@$DIR/inline_coroutine.rs:20:5: 20:8}> { __pointer: copy _3 };
++ _2 = Pin::<&mut {coroutine@$DIR/inline_coroutine.rs:20:5: 20:8}> { pointer: copy _3 };
+ StorageDead(_3);
+ StorageLive(_5);
+ _5 = const false;
diff --git a/tests/mir-opt/inline_coroutine_body.run2-{closure#0}.Inline.panic-abort.diff b/tests/mir-opt/inline_coroutine_body.run2-{closure#0}.Inline.panic-abort.diff
index e49d7cea28e58..1e9a6dd4f5c8f 100644
--- a/tests/mir-opt/inline_coroutine_body.run2-{closure#0}.Inline.panic-abort.diff
+++ b/tests/mir-opt/inline_coroutine_body.run2-{closure#0}.Inline.panic-abort.diff
@@ -121,7 +121,7 @@
- }
-
- bb2: {
-+ _4 = Pin::<&mut {async fn body of ActionPermit<'_, T>::perform()}> { __pointer: copy _5 };
++ _4 = Pin::<&mut {async fn body of ActionPermit<'_, T>::perform()}> { pointer: copy _5 };
StorageDead(_5);
StorageLive(_6);
StorageLive(_7);
@@ -218,7 +218,7 @@
+ _37 = deref_copy (_8.0: &mut {async fn body of ActionPermit<'_, T>::perform()});
+ _21 = &mut (((*_37) as variant#3).1: std::future::Ready<()>);
+ _20 = &mut (*_21);
-+ _19 = Pin::<&mut std::future::Ready<()>> { __pointer: copy _20 };
++ _19 = Pin::<&mut std::future::Ready<()>> { pointer: copy _20 };
+ StorageDead(_20);
+ StorageLive(_22);
+ StorageLive(_23);
@@ -239,7 +239,7 @@
+ _48 = &mut (_19.0: &mut std::future::Ready<()>);
+ _45 = copy (_19.0: &mut std::future::Ready<()>);
+ StorageDead(_48);
-+ _47 = Pin::<&mut std::future::Ready<()>> { __pointer: copy _45 };
++ _47 = Pin::<&mut std::future::Ready<()>> { pointer: copy _45 };
+ StorageDead(_47);
+ _44 = &mut ((*_45).0: std::option::Option<()>);
+ StorageLive(_49);
diff --git a/tests/mir-opt/inline_coroutine_body.run2-{closure#0}.Inline.panic-unwind.diff b/tests/mir-opt/inline_coroutine_body.run2-{closure#0}.Inline.panic-unwind.diff
index e7aed556f2d71..94b89a310baa8 100644
--- a/tests/mir-opt/inline_coroutine_body.run2-{closure#0}.Inline.panic-unwind.diff
+++ b/tests/mir-opt/inline_coroutine_body.run2-{closure#0}.Inline.panic-unwind.diff
@@ -123,7 +123,7 @@
- }
-
- bb2: {
-+ _4 = Pin::<&mut {async fn body of ActionPermit<'_, T>::perform()}> { __pointer: copy _5 };
++ _4 = Pin::<&mut {async fn body of ActionPermit<'_, T>::perform()}> { pointer: copy _5 };
StorageDead(_5);
StorageLive(_6);
StorageLive(_7);
@@ -235,7 +235,7 @@
+ _37 = deref_copy (_8.0: &mut {async fn body of ActionPermit<'_, T>::perform()});
+ _21 = &mut (((*_37) as variant#3).1: std::future::Ready<()>);
+ _20 = &mut (*_21);
-+ _19 = Pin::<&mut std::future::Ready<()>> { __pointer: copy _20 };
++ _19 = Pin::<&mut std::future::Ready<()>> { pointer: copy _20 };
+ StorageDead(_20);
+ StorageLive(_22);
+ StorageLive(_23);
@@ -256,7 +256,7 @@
+ _50 = &mut (_19.0: &mut std::future::Ready<()>);
+ _47 = copy (_19.0: &mut std::future::Ready<()>);
+ StorageDead(_50);
-+ _49 = Pin::<&mut std::future::Ready<()>> { __pointer: copy _47 };
++ _49 = Pin::<&mut std::future::Ready<()>> { pointer: copy _47 };
+ StorageDead(_49);
+ _46 = &mut ((*_47).0: std::option::Option<()>);
+ StorageLive(_51);
diff --git a/tests/pretty/postfix-yield.rs b/tests/pretty/postfix-yield.rs
index f76e8142ae86c..60380a4071c54 100644
--- a/tests/pretty/postfix-yield.rs
+++ b/tests/pretty/postfix-yield.rs
@@ -2,7 +2,8 @@
//@ edition: 2024
//@ pp-exact
-#![feature(gen_blocks, coroutines, coroutine_trait, yield_expr)]
+#![feature(gen_blocks, coroutines, coroutine_trait, yield_expr,
+stmt_expr_attributes)]
use std::ops::{Coroutine, CoroutineState};
use std::pin::pin;
diff --git a/tests/ui/async-await/pin-ergonomics/reborrow-once.stderr b/tests/ui/async-await/pin-ergonomics/reborrow-once.stderr
index a1ea2b4a57a70..dc8e424ad2a42 100644
--- a/tests/ui/async-await/pin-ergonomics/reborrow-once.stderr
+++ b/tests/ui/async-await/pin-ergonomics/reborrow-once.stderr
@@ -1,4 +1,4 @@
-error[E0499]: cannot borrow `*x.__pointer` as mutable more than once at a time
+error[E0499]: cannot borrow `*x.pointer` as mutable more than once at a time
--> $DIR/reborrow-once.rs:12:14
|
LL | twice(x, x);
diff --git a/tests/ui/coroutine/postfix-yield.rs b/tests/ui/coroutine/postfix-yield.rs
index ff843138c8c2c..f2fdcebdaa9a9 100644
--- a/tests/ui/coroutine/postfix-yield.rs
+++ b/tests/ui/coroutine/postfix-yield.rs
@@ -3,7 +3,7 @@
//@ run-pass
//@ edition: 2024
-#![feature(gen_blocks, coroutines, coroutine_trait, yield_expr)]
+#![feature(gen_blocks, coroutines, coroutine_trait, yield_expr, stmt_expr_attributes)]
use std::ops::{Coroutine, CoroutineState};
use std::pin::pin;
diff --git a/tests/ui/pin-macro/lifetime_errors_on_promotion_misusage.rs b/tests/ui/pin-macro/lifetime_errors_on_promotion_misusage.rs
index 8a0244e8145a7..e505fe435207c 100644
--- a/tests/ui/pin-macro/lifetime_errors_on_promotion_misusage.rs
+++ b/tests/ui/pin-macro/lifetime_errors_on_promotion_misusage.rs
@@ -9,14 +9,14 @@ use core::{
fn function_call_stops_borrow_extension() {
let phantom_pinned = identity(pin!(PhantomPinned));
- //~^ ERROR temporary value dropped while borrowed
+ //~^ ERROR does not live long enough
stuff(phantom_pinned)
}
fn promotion_only_works_for_the_innermost_block() {
let phantom_pinned = {
let phantom_pinned = pin!(PhantomPinned);
- //~^ ERROR temporary value dropped while borrowed
+ //~^ ERROR does not live long enough
phantom_pinned
};
stuff(phantom_pinned)
diff --git a/tests/ui/pin-macro/lifetime_errors_on_promotion_misusage.stderr b/tests/ui/pin-macro/lifetime_errors_on_promotion_misusage.stderr
index 9df7f0ffd0c3f..43fb82be7c2f0 100644
--- a/tests/ui/pin-macro/lifetime_errors_on_promotion_misusage.stderr
+++ b/tests/ui/pin-macro/lifetime_errors_on_promotion_misusage.stderr
@@ -1,35 +1,29 @@
-error[E0716]: temporary value dropped while borrowed
+error[E0597]: value does not live long enough
--> $DIR/lifetime_errors_on_promotion_misusage.rs:11:35
|
LL | let phantom_pinned = identity(pin!(PhantomPinned));
- | ^^^^^^^^^^^^^^^^^^^ - temporary value is freed at the end of this statement
+ | ^^^^^^^^^^^^^^^^^^^ - value dropped here while still borrowed
| |
- | creates a temporary value which is freed while still in use
+ | borrowed value does not live long enough
LL |
LL | stuff(phantom_pinned)
| -------------- borrow later used here
|
= note: this error originates in the macro `pin` (in Nightly builds, run with -Z macro-backtrace for more info)
-help: consider using a `let` binding to create a longer lived value
- |
-LL ~ let binding = pin!(PhantomPinned);
-LL ~ let phantom_pinned = identity(binding);
- |
-error[E0716]: temporary value dropped while borrowed
+error[E0597]: value does not live long enough
--> $DIR/lifetime_errors_on_promotion_misusage.rs:18:30
|
LL | let phantom_pinned = {
| -------------- borrow later stored here
LL | let phantom_pinned = pin!(PhantomPinned);
- | ^^^^^^^^^^^^^^^^^^^ creates a temporary value which is freed while still in use
+ | ^^^^^^^^^^^^^^^^^^^ borrowed value does not live long enough
...
LL | };
- | - temporary value is freed at the end of this statement
+ | - value dropped here while still borrowed
|
- = note: consider using a `let` binding to create a longer lived value
= note: this error originates in the macro `pin` (in Nightly builds, run with -Z macro-backtrace for more info)
error: aborting due to 2 previous errors
-For more information about this error, try `rustc --explain E0716`.
+For more information about this error, try `rustc --explain E0597`.
diff --git a/tests/ui/pin-macro/pin_move.stderr b/tests/ui/pin-macro/pin_move.stderr
index c9b8ad9b2021f..3f46602098850 100644
--- a/tests/ui/pin-macro/pin_move.stderr
+++ b/tests/ui/pin-macro/pin_move.stderr
@@ -31,6 +31,11 @@ LL | struct NotCopy<T>(T);
LL | let mut pointee = NotCopy(PhantomPinned);
LL | pin!(*&mut pointee);
| ------------- you could clone this value
+help: consider removing the dereference here
+ |
+LL - pin!(*&mut pointee);
+LL + pin!(&mut pointee);
+ |
error: aborting due to 2 previous errors
From 5523c87c41b357fe3c3047dabf603f18830eeaf8 Mon Sep 17 00:00:00 2001
From: Mara Bos <m-ou.se@m-ou.se>
Date: Thu, 17 Apr 2025 21:16:58 +0200
Subject: [PATCH 4/4] Update libcore.natvis for Pin.
---
src/etc/natvis/libcore.natvis | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/src/etc/natvis/libcore.natvis b/src/etc/natvis/libcore.natvis
index 8a441cf209356..8fe87a999895c 100644
--- a/src/etc/natvis/libcore.natvis
+++ b/src/etc/natvis/libcore.natvis
@@ -69,9 +69,9 @@
</Type>
<Type Name="core::pin::Pin<*>">
- <DisplayString>Pin({(void*)__pointer}: {__pointer})</DisplayString>
+ <DisplayString>Pin({(void*)pointer}: {pointer})</DisplayString>
<Expand>
- <ExpandedItem>__pointer</ExpandedItem>
+ <ExpandedItem>pointer</ExpandedItem>
</Expand>
</Type>