Auto merge of rust-lang#80422 - RalfJung:weak-no-unsized-raw, r=Mark-…

…Simulacrum

de-stabilize unsized raw ptr methods for Weak

`@Mark-Simulacrum` this is the patch re: rust-lang#80407.

I couldn't figure out the branch it needs to go on though, stable is still the old stable but beta already the new beta...?

library/alloc/src/rc.rs

@@ -1749,7 +1749,7 @@ struct WeakInner<'a> {
     strong: &'a Cell<usize>,
 }
 
-impl<T: ?Sized> Weak<T> {
+impl<T> Weak<T> {
     /// Returns a raw pointer to the object `T` pointed to by this `Weak<T>`.
     ///
     /// The pointer is valid only if there are some strong references. The pointer may be dangling,
@@ -1882,7 +1882,9 @@ impl<T: ?Sized> Weak<T> {
         // SAFETY: we now have recovered the original Weak pointer, so can create the Weak.
         Weak { ptr: unsafe { NonNull::new_unchecked(ptr) } }
     }
+}
 
+impl<T: ?Sized> Weak<T> {
     /// Attempts to upgrade the `Weak` pointer to an [`Rc`], delaying
     /// dropping of the inner value if successful.
     ///

library/alloc/src/rc/tests.rs

@@ -208,30 +208,6 @@ fn into_from_weak_raw() {
     }
 }
 
-#[test]
-fn test_into_from_weak_raw_unsized() {
-    use std::fmt::Display;
-    use std::string::ToString;
-
-    let arc: Rc<str> = Rc::from("foo");
-    let weak: Weak<str> = Rc::downgrade(&arc);
-
-    let ptr = Weak::into_raw(weak.clone());
-    let weak2 = unsafe { Weak::from_raw(ptr) };
-
-    assert_eq!(unsafe { &*ptr }, "foo");
-    assert!(weak.ptr_eq(&weak2));
-
-    let arc: Rc<dyn Display> = Rc::new(123);
-    let weak: Weak<dyn Display> = Rc::downgrade(&arc);
-
-    let ptr = Weak::into_raw(weak.clone());
-    let weak2 = unsafe { Weak::from_raw(ptr) };
-
-    assert_eq!(unsafe { &*ptr }.to_string(), "123");
-    assert!(weak.ptr_eq(&weak2));
-}
-
 #[test]
 fn get_mut() {
     let mut x = Rc::new(3);

library/alloc/src/sync.rs

@@ -1535,7 +1535,7 @@ struct WeakInner<'a> {
     strong: &'a atomic::AtomicUsize,
 }
 
-impl<T: ?Sized> Weak<T> {
+impl<T> Weak<T> {
     /// Returns a raw pointer to the object `T` pointed to by this `Weak<T>`.
     ///
     /// The pointer is valid only if there are some strong references. The pointer may be dangling,
@@ -1668,7 +1668,9 @@ impl<T: ?Sized> Weak<T> {
         // SAFETY: we now have recovered the original Weak pointer, so can create the Weak.
         unsafe { Weak { ptr: NonNull::new_unchecked(ptr) } }
     }
+}
 
+impl<T: ?Sized> Weak<T> {
     /// Attempts to upgrade the `Weak` pointer to an [`Arc`], delaying
     /// dropping of the inner value if successful.
     ///

library/alloc/src/sync/tests.rs

@@ -158,30 +158,6 @@ fn into_from_weak_raw() {
     }
 }
 
-#[test]
-fn test_into_from_weak_raw_unsized() {
-    use std::fmt::Display;
-    use std::string::ToString;
-
-    let arc: Arc<str> = Arc::from("foo");
-    let weak: Weak<str> = Arc::downgrade(&arc);
-
-    let ptr = Weak::into_raw(weak.clone());
-    let weak2 = unsafe { Weak::from_raw(ptr) };
-
-    assert_eq!(unsafe { &*ptr }, "foo");
-    assert!(weak.ptr_eq(&weak2));
-
-    let arc: Arc<dyn Display> = Arc::new(123);
-    let weak: Weak<dyn Display> = Arc::downgrade(&arc);
-
-    let ptr = Weak::into_raw(weak.clone());
-    let weak2 = unsafe { Weak::from_raw(ptr) };
-
-    assert_eq!(unsafe { &*ptr }.to_string(), "123");
-    assert!(weak.ptr_eq(&weak2));
-}
-
 #[test]
 fn test_cowarc_clone_make_mut() {
     let mut cow0 = Arc::new(75);