Rollup merge of rust-lang#103702 - WaffleLapkin:lift-sized-bounds-from-pointer-methods-where-applicable, r=m-ou-se

Lift `T: Sized` bounds from some `strict_provenance` pointer methods

This PR removes requirement for `T` (pointee type) to be `Sized` to call `pointer::{addr, expose_addr, with_addr, map_addr}`. These functions don't use `T`'s size, so there is no reason for them to require this. Updated public API:

cc ``@Gankra,`` rust-lang#95228
r? libs-api

Author: Dylan-DPC

library/core/src/ptr/const_ptr.rs

@@ -202,14 +202,11 @@ impl<T: ?Sized> *const T {
     #[must_use]
     #[inline(always)]
     #[unstable(feature = "strict_provenance", issue = "95228")]
-    pub fn addr(self) -> usize
-    where
-        T: Sized,
-    {
+    pub fn addr(self) -> usize {
         // FIXME(strict_provenance_magic): I am magic and should be a compiler intrinsic.
         // SAFETY: Pointer-to-integer transmutes are valid (if you are okay with losing the
         // provenance).
-        unsafe { mem::transmute(self) }
+        unsafe { mem::transmute(self.cast::<()>()) }
     }
 
     /// Gets the "address" portion of the pointer, and 'exposes' the "provenance" part for future
@@ -239,12 +236,9 @@ impl<T: ?Sized> *const T {
     #[must_use]
     #[inline(always)]
     #[unstable(feature = "strict_provenance", issue = "95228")]
-    pub fn expose_addr(self) -> usize
-    where
-        T: Sized,
-    {
+    pub fn expose_addr(self) -> usize {
         // FIXME(strict_provenance_magic): I am magic and should be a compiler intrinsic.
-        self as usize
+        self.cast::<()>() as usize
     }
 
     /// Creates a new pointer with the given address.
@@ -262,10 +256,7 @@ impl<T: ?Sized> *const T {
     #[must_use]
     #[inline]
     #[unstable(feature = "strict_provenance", issue = "95228")]
-    pub fn with_addr(self, addr: usize) -> Self
-    where
-        T: Sized,
-    {
+    pub fn with_addr(self, addr: usize) -> Self {
         // FIXME(strict_provenance_magic): I am magic and should be a compiler intrinsic.
         //
         // In the mean-time, this operation is defined to be "as if" it was
@@ -288,10 +279,7 @@ impl<T: ?Sized> *const T {
     #[must_use]
     #[inline]
     #[unstable(feature = "strict_provenance", issue = "95228")]
-    pub fn map_addr(self, f: impl FnOnce(usize) -> usize) -> Self
-    where
-        T: Sized,
-    {
+    pub fn map_addr(self, f: impl FnOnce(usize) -> usize) -> Self {
         self.with_addr(f(self.addr()))
     }
 

library/core/src/ptr/mut_ptr.rs

@@ -208,14 +208,11 @@ impl<T: ?Sized> *mut T {
     #[must_use]
     #[inline(always)]
     #[unstable(feature = "strict_provenance", issue = "95228")]
-    pub fn addr(self) -> usize
-    where
-        T: Sized,
-    {
+    pub fn addr(self) -> usize {
         // FIXME(strict_provenance_magic): I am magic and should be a compiler intrinsic.
         // SAFETY: Pointer-to-integer transmutes are valid (if you are okay with losing the
         // provenance).
-        unsafe { mem::transmute(self) }
+        unsafe { mem::transmute(self.cast::<()>()) }
     }
 
     /// Gets the "address" portion of the pointer, and 'exposes' the "provenance" part for future
@@ -245,12 +242,9 @@ impl<T: ?Sized> *mut T {
     #[must_use]
     #[inline(always)]
     #[unstable(feature = "strict_provenance", issue = "95228")]
-    pub fn expose_addr(self) -> usize
-    where
-        T: Sized,
-    {
+    pub fn expose_addr(self) -> usize {
         // FIXME(strict_provenance_magic): I am magic and should be a compiler intrinsic.
-        self as usize
+        self.cast::<()>() as usize
     }
 
     /// Creates a new pointer with the given address.
@@ -268,10 +262,7 @@ impl<T: ?Sized> *mut T {
     #[must_use]
     #[inline]
     #[unstable(feature = "strict_provenance", issue = "95228")]
-    pub fn with_addr(self, addr: usize) -> Self
-    where
-        T: Sized,
-    {
+    pub fn with_addr(self, addr: usize) -> Self {
         // FIXME(strict_provenance_magic): I am magic and should be a compiler intrinsic.
         //
         // In the mean-time, this operation is defined to be "as if" it was
@@ -294,10 +285,7 @@ impl<T: ?Sized> *mut T {
     #[must_use]
     #[inline]
     #[unstable(feature = "strict_provenance", issue = "95228")]
-    pub fn map_addr(self, f: impl FnOnce(usize) -> usize) -> Self
-    where
-        T: Sized,
-    {
+    pub fn map_addr(self, f: impl FnOnce(usize) -> usize) -> Self {
         self.with_addr(f(self.addr()))
     }
 

library/core/src/ptr/non_null.rs

@@ -268,10 +268,7 @@ impl<T: ?Sized> NonNull<T> {
     #[must_use]
     #[inline]
     #[unstable(feature = "strict_provenance", issue = "95228")]
-    pub fn addr(self) -> NonZeroUsize
-    where
-        T: Sized,
-    {
+    pub fn addr(self) -> NonZeroUsize {
         // SAFETY: The pointer is guaranteed by the type to be non-null,
         // meaning that the address will be non-zero.
         unsafe { NonZeroUsize::new_unchecked(self.pointer.addr()) }
@@ -286,10 +283,7 @@ impl<T: ?Sized> NonNull<T> {
     #[must_use]
     #[inline]
     #[unstable(feature = "strict_provenance", issue = "95228")]
-    pub fn with_addr(self, addr: NonZeroUsize) -> Self
-    where
-        T: Sized,
-    {
+    pub fn with_addr(self, addr: NonZeroUsize) -> Self {
         // SAFETY: The result of `ptr::from::with_addr` is non-null because `addr` is guaranteed to be non-zero.
         unsafe { NonNull::new_unchecked(self.pointer.with_addr(addr.get()) as *mut _) }
     }
@@ -303,10 +297,7 @@ impl<T: ?Sized> NonNull<T> {
     #[must_use]
     #[inline]
     #[unstable(feature = "strict_provenance", issue = "95228")]
-    pub fn map_addr(self, f: impl FnOnce(NonZeroUsize) -> NonZeroUsize) -> Self
-    where
-        T: Sized,
-    {
+    pub fn map_addr(self, f: impl FnOnce(NonZeroUsize) -> NonZeroUsize) -> Self {
         self.with_addr(f(self.addr()))
     }