From 8b4995aad878f6b5d3f322dc161e6b772541151c Mon Sep 17 00:00:00 2001
From: Michael Goulet <michael@errs.io>
Date: Wed, 20 Nov 2024 02:46:56 +0000
Subject: [PATCH] Make PointerLike opt-in as a trait

---
 alloc/src/boxed.rs |  6 ++++++
 alloc/src/lib.rs   |  1 +
 core/src/marker.rs | 12 ++++++++++++
 3 files changed, 19 insertions(+)

diff --git a/alloc/src/boxed.rs b/alloc/src/boxed.rs
index ac3e4626ee5eb..ee60ec0fbacbe 100644
--- a/alloc/src/boxed.rs
+++ b/alloc/src/boxed.rs
@@ -191,6 +191,8 @@ use core::error::{self, Error};
 use core::fmt;
 use core::future::Future;
 use core::hash::{Hash, Hasher};
+#[cfg(not(bootstrap))]
+use core::marker::PointerLike;
 use core::marker::{Tuple, Unsize};
 use core::mem::{self, SizedTypeProperties};
 use core::ops::{
@@ -2131,3 +2133,7 @@ impl<E: Error> Error for Box<E> {
         Error::provide(&**self, request);
     }
 }
+
+#[cfg(not(bootstrap))]
+#[unstable(feature = "pointer_like_trait", issue = "none")]
+impl<T> PointerLike for Box<T> {}
diff --git a/alloc/src/lib.rs b/alloc/src/lib.rs
index 7839fe04b8d03..041ff37897f05 100644
--- a/alloc/src/lib.rs
+++ b/alloc/src/lib.rs
@@ -136,6 +136,7 @@
 #![feature(panic_internals)]
 #![feature(pattern)]
 #![feature(pin_coerce_unsized_trait)]
+#![feature(pointer_like_trait)]
 #![feature(ptr_internals)]
 #![feature(ptr_metadata)]
 #![feature(ptr_sub_ptr)]
diff --git a/core/src/marker.rs b/core/src/marker.rs
index 1c5c58d64a2b2..c8ea52a1fb0b4 100644
--- a/core/src/marker.rs
+++ b/core/src/marker.rs
@@ -981,6 +981,18 @@ pub trait Tuple {}
 )]
 pub trait PointerLike {}
 
+#[cfg(not(bootstrap))]
+marker_impls! {
+    #[unstable(feature = "pointer_like_trait", issue = "none")]
+    PointerLike for
+        usize,
+        {T} &T,
+        {T} &mut T,
+        {T} *const T,
+        {T} *mut T,
+        {T: PointerLike} crate::pin::Pin<T>,
+}
+
 /// A marker for types which can be used as types of `const` generic parameters.
 ///
 /// These types must have a proper equivalence relation (`Eq`) and it must be automatically