Auto merge of #62355 - Centril:rollup-xnxtcgm, r=Centril

Rollup of 16 pull requests

Successful merges:

 - #62039 (Remove needless lifetimes (rustc))
 - #62173 (rename InterpretCx -> InterpCx)
 - #62240 (wfcheck: resolve the type-vars in `AdtField` types)
 - #62249 (Use mem::take instead of mem::replace with default)
 - #62252 (Update mem::replace example to not be identical to mem::take)
 - #62258 (syntax: Unsupport `foo! bar { ... }` macros in the parser)
 - #62268 (Clean up inherent_impls)
 - #62287 (Use link attributes on extern "C" blocks with llvm-libuwind)
 - #62295 (miri realloc: do not require giving old size+align)
 - #62297 (refactor check_for_substitution)
 - #62316 (When possible without changing semantics, implement Iterator::last in terms of DoubleEndedIterator::next_back for types in liballoc and libcore.)
 - #62317 (Migrate `compile-pass` annotations to `build-pass`)
 - #62337 (Fix bucket in CPU usage script)
 - #62344 (simplify Option::get_or_insert)
 - #62346 (enable a few more tests in Miri and update the comment for others)
 - #62351 (remove bogus example from drop_in_place)

Failed merges:

r? @ghost

1 files changed, 5 insertions, 27 deletions

diff --git a/src/libcore/ptr/mod.rs b/src/libcore/ptr/mod.rs
index fccb00d768c..da781d7e9fe 100644
--- a/src/libcore/ptr/mod.rs
+++ b/src/libcore/ptr/mod.rs
@@ -100,7 +100,11 @@ pub use unique::Unique;
 ///   as the compiler doesn't need to prove that it's sound to elide the
 ///   copy.
 ///
+/// Unaligned values cannot be dropped in place, they must be copied to an aligned
+/// location first using [`ptr::read_unaligned`].
+///
 /// [`ptr::read`]: ../ptr/fn.read.html
+/// [`ptr::read_unaligned`]: ../ptr/fn.read_unaligned.html
 ///
 /// # Safety
 ///
@@ -108,8 +112,7 @@ pub use unique::Unique;
 ///
 /// * `to_drop` must be [valid] for reads.
 ///
-/// * `to_drop` must be properly aligned. See the example below for how to drop
-///   an unaligned pointer.
+/// * `to_drop` must be properly aligned.
 ///
 /// Additionally, if `T` is not [`Copy`], using the pointed-to value after
 /// calling `drop_in_place` can cause undefined behavior. Note that `*to_drop =
@@ -153,31 +156,6 @@ pub use unique::Unique;
 /// assert!(weak.upgrade().is_none());
 /// ```
 ///
-/// Unaligned values cannot be dropped in place, they must be copied to an aligned
-/// location first:
-/// ```
-/// use std::ptr;
-/// use std::mem::{self, MaybeUninit};
-///
-/// unsafe fn drop_after_copy<T>(to_drop: *mut T) {
-///     let mut copy: MaybeUninit<T> = MaybeUninit::uninit();
-///     ptr::copy(to_drop, copy.as_mut_ptr(), 1);
-///     drop(copy.assume_init());
-/// }
-///
-/// #[repr(packed, C)]
-/// struct Packed {
-///     _padding: u8,
-///     unaligned: Vec<i32>,
-/// }
-///
-/// let mut p = Packed { _padding: 0, unaligned: vec![42] };
-/// unsafe {
-///     drop_after_copy(&mut p.unaligned as *mut _);
-///     mem::forget(p);
-/// }
-/// ```
-///
 /// Notice that the compiler performs this copy automatically when dropping packed structs,
 /// i.e., you do not usually have to worry about such issues unless you call `drop_in_place`
 /// manually.