Auto merge of #128761 - matthiaskrgr:rollup-5p1mlqq, r=matthiaskrgr

Rollup of 9 pull requests

Successful merges:

 - #124944 (On trait bound mismatch, detect multiple crate versions in dep tree)
 - #125048 (PinCoerceUnsized trait into core)
 - #128406 (implement BufReader::peek)
 - #128539 (Forbid unused unsafe in vxworks-specific std modules)
 - #128687 (interpret: refactor function call handling to be better-abstracted)
 - #128692 (Add a triagebot mention for `library/Cargo.lock`)
 - #128710 (Don't ICE when getting an input file name's stem fails)
 - #128718 (Consider `cfg_attr` checked by `CheckAttrVisitor`)
 - #128751 (std::thread: set_name implementation proposal for vxWorks.)

r? `@ghost`
`@rustbot` modify labels: rollup

8 files changed, 91 insertions, 2 deletions

diff --git a/library/alloc/src/boxed.rs b/library/alloc/src/boxed.rs
index 38f50955b12..7de41259599 100644
--- a/library/alloc/src/boxed.rs
+++ b/library/alloc/src/boxed.rs
@@ -200,7 +200,7 @@ use core::ops::{
     AsyncFn, AsyncFnMut, AsyncFnOnce, CoerceUnsized, Coroutine, CoroutineState, Deref, DerefMut,
     DerefPure, DispatchFromDyn, Receiver,
 };
-use core::pin::Pin;
+use core::pin::{Pin, PinCoerceUnsized};
 use core::ptr::{self, addr_of_mut, NonNull, Unique};
 use core::task::{Context, Poll};
 use core::{borrow, fmt, slice};
@@ -2726,3 +2726,6 @@ impl<T: core::error::Error> core::error::Error for Box<T> {
         core::error::Error::provide(&**self, request);
     }
 }
+
+#[unstable(feature = "pin_coerce_unsized_trait", issue = "123430")]
+unsafe impl<T: ?Sized, A: Allocator> PinCoerceUnsized for Box<T, A> {}
diff --git a/library/alloc/src/lib.rs b/library/alloc/src/lib.rs
index 28b08ef5611..3e44adf73f0 100644
--- a/library/alloc/src/lib.rs
+++ b/library/alloc/src/lib.rs
@@ -138,6 +138,7 @@
 #![feature(maybe_uninit_uninit_array_transpose)]
 #![feature(panic_internals)]
 #![feature(pattern)]
+#![feature(pin_coerce_unsized_trait)]
 #![feature(ptr_internals)]
 #![feature(ptr_metadata)]
 #![feature(ptr_sub_ptr)]
diff --git a/library/alloc/src/rc.rs b/library/alloc/src/rc.rs
index 13d218e43a7..bdee06154fa 100644
--- a/library/alloc/src/rc.rs
+++ b/library/alloc/src/rc.rs
@@ -256,6 +256,7 @@ use core::ops::{CoerceUnsized, Deref, DerefMut, DerefPure, DispatchFromDyn, Rece
 use core::panic::{RefUnwindSafe, UnwindSafe};
 #[cfg(not(no_global_oom_handling))]
 use core::pin::Pin;
+use core::pin::PinCoerceUnsized;
 use core::ptr::{self, drop_in_place, NonNull};
 #[cfg(not(no_global_oom_handling))]
 use core::slice::from_raw_parts_mut;
@@ -2177,6 +2178,12 @@ impl<T: ?Sized, A: Allocator> Deref for Rc<T, A> {
     }
 }
 
+#[unstable(feature = "pin_coerce_unsized_trait", issue = "123430")]
+unsafe impl<T: ?Sized, A: Allocator> PinCoerceUnsized for Rc<T, A> {}
+
+#[unstable(feature = "pin_coerce_unsized_trait", issue = "123430")]
+unsafe impl<T: ?Sized, A: Allocator> PinCoerceUnsized for Weak<T, A> {}
+
 #[unstable(feature = "deref_pure_trait", issue = "87121")]
 unsafe impl<T: ?Sized, A: Allocator> DerefPure for Rc<T, A> {}
 
@@ -3691,6 +3698,9 @@ impl<T: ?Sized, A: Allocator> Deref for UniqueRc<T, A> {
     }
 }
 
+#[unstable(feature = "pin_coerce_unsized_trait", issue = "123430")]
+unsafe impl<T: ?Sized> PinCoerceUnsized for UniqueRc<T> {}
+
 #[unstable(feature = "unique_rc_arc", issue = "112566")]
 impl<T: ?Sized, A: Allocator> DerefMut for UniqueRc<T, A> {
     fn deref_mut(&mut self) -> &mut T {
diff --git a/library/alloc/src/sync.rs b/library/alloc/src/sync.rs
index 3ad0dae77db..2c0d19b0ada 100644
--- a/library/alloc/src/sync.rs
+++ b/library/alloc/src/sync.rs
@@ -20,7 +20,7 @@ use core::marker::{PhantomData, Unsize};
 use core::mem::{self, align_of_val_raw, ManuallyDrop};
 use core::ops::{CoerceUnsized, Deref, DerefPure, DispatchFromDyn, Receiver};
 use core::panic::{RefUnwindSafe, UnwindSafe};
-use core::pin::Pin;
+use core::pin::{Pin, PinCoerceUnsized};
 use core::ptr::{self, NonNull};
 #[cfg(not(no_global_oom_handling))]
 use core::slice::from_raw_parts_mut;
@@ -2142,6 +2142,12 @@ impl<T: ?Sized, A: Allocator> Deref for Arc<T, A> {
     }
 }
 
+#[unstable(feature = "pin_coerce_unsized_trait", issue = "123430")]
+unsafe impl<T: ?Sized, A: Allocator> PinCoerceUnsized for Arc<T, A> {}
+
+#[unstable(feature = "pin_coerce_unsized_trait", issue = "123430")]
+unsafe impl<T: ?Sized, A: Allocator> PinCoerceUnsized for Weak<T, A> {}
+
 #[unstable(feature = "deref_pure_trait", issue = "87121")]
 unsafe impl<T: ?Sized, A: Allocator> DerefPure for Arc<T, A> {}
 
diff --git a/library/alloc/tests/arc.rs b/library/alloc/tests/arc.rs
index c37a80dca95..dc27c578b57 100644
--- a/library/alloc/tests/arc.rs
+++ b/library/alloc/tests/arc.rs
@@ -227,3 +227,17 @@ fn make_mut_unsized() {
     assert_eq!(*data, [11, 21, 31]);
     assert_eq!(*other_data, [110, 20, 30]);
 }
+
+#[allow(unused)]
+mod pin_coerce_unsized {
+    use alloc::sync::Arc;
+    use core::pin::Pin;
+
+    pub trait MyTrait {}
+    impl MyTrait for String {}
+
+    // Pin coercion should work for Arc
+    pub fn pin_arc(arg: Pin<Arc<String>>) -> Pin<Arc<dyn MyTrait>> {
+        arg
+    }
+}
diff --git a/library/alloc/tests/boxed.rs b/library/alloc/tests/boxed.rs
index 4cacee0414d..faee64b2f67 100644
--- a/library/alloc/tests/boxed.rs
+++ b/library/alloc/tests/boxed.rs
@@ -179,3 +179,40 @@ unsafe impl Allocator for ConstAllocator {
         self
     }
 }
+
+#[allow(unused)]
+mod pin_coerce_unsized {
+    use alloc::boxed::Box;
+    use core::pin::Pin;
+
+    trait MyTrait {
+        fn action(&self) -> &str;
+    }
+    impl MyTrait for String {
+        fn action(&self) -> &str {
+            &*self
+        }
+    }
+    struct MyStruct;
+    impl MyTrait for MyStruct {
+        fn action(&self) -> &str {
+            "MyStruct"
+        }
+    }
+
+    // Pin coercion should work for Box
+    fn pin_box<T: MyTrait + 'static>(arg: Pin<Box<T>>) -> Pin<Box<dyn MyTrait>> {
+        arg
+    }
+
+    #[test]
+    fn pin_coerce_unsized_box() {
+        let my_string = "my string";
+        let a_string = Box::pin(String::from(my_string));
+        let pin_box_str = pin_box(a_string);
+        assert_eq!(pin_box_str.as_ref().action(), my_string);
+        let a_struct = Box::pin(MyStruct);
+        let pin_box_struct = pin_box(a_struct);
+        assert_eq!(pin_box_struct.as_ref().action(), "MyStruct");
+    }
+}
diff --git a/library/alloc/tests/lib.rs b/library/alloc/tests/lib.rs
index 89538f272f0..3d4add6fae4 100644
--- a/library/alloc/tests/lib.rs
+++ b/library/alloc/tests/lib.rs
@@ -40,6 +40,7 @@
 #![feature(drain_keep_rest)]
 #![feature(local_waker)]
 #![feature(vec_pop_if)]
+#![feature(unique_rc_arc)]
 #![allow(internal_features)]
 #![deny(fuzzy_provenance_casts)]
 #![deny(unsafe_op_in_unsafe_fn)]
diff --git a/library/alloc/tests/rc.rs b/library/alloc/tests/rc.rs
index 499740e738a..29dbdcf225e 100644
--- a/library/alloc/tests/rc.rs
+++ b/library/alloc/tests/rc.rs
@@ -205,3 +205,20 @@ fn weak_may_dangle() {
     // `val` dropped here while still borrowed
     // borrow might be used here, when `val` is dropped and runs the `Drop` code for type `std::rc::Weak`
 }
+
+#[allow(unused)]
+mod pin_coerce_unsized {
+    use alloc::rc::{Rc, UniqueRc};
+    use core::pin::Pin;
+
+    pub trait MyTrait {}
+    impl MyTrait for String {}
+
+    // Pin coercion should work for Rc
+    pub fn pin_rc(arg: Pin<Rc<String>>) -> Pin<Rc<dyn MyTrait>> {
+        arg
+    }
+    pub fn pin_unique_rc(arg: Pin<UniqueRc<String>>) -> Pin<UniqueRc<dyn MyTrait>> {
+        arg
+    }
+}