From a329a61b9bf01bfc3f9f7316bb800b2bc8b76382 Mon Sep 17 00:00:00 2001
From: Richo Healey <richo@psych0tik.net>
Date: Tue, 7 Apr 2015 00:40:22 -0700
Subject: [PATCH] alloc: impl fmt::Pointer for Rc, Arc and Box

Closes #24091
---
 src/liballoc/arc.rs                    |  7 +++++++
 src/liballoc/boxed.rs                  | 10 +++++++++
 src/liballoc/rc.rs                     |  7 +++++++
 src/libcore/ptr.rs                     |  8 ++++++++
 src/libsyntax/ptr.rs                   |  7 +++++++
 src/test/run-pass/fmt-pointer-trait.rs | 28 ++++++++++++++++++++++++++
 6 files changed, 67 insertions(+)
 create mode 100644 src/test/run-pass/fmt-pointer-trait.rs

diff --git a/src/liballoc/arc.rs b/src/liballoc/arc.rs
index 68bde147611..ff176d81591 100644
--- a/src/liballoc/arc.rs
+++ b/src/liballoc/arc.rs
@@ -668,6 +668,13 @@ impl<T: fmt::Debug> fmt::Debug for Arc<T> {
     }
 }
 
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> fmt::Pointer for Arc<T> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Pointer::fmt(&*self._ptr, f)
+    }
+}
+
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: Default + Sync + Send> Default for Arc<T> {
     #[stable(feature = "rust1", since = "1.0.0")]
diff --git a/src/liballoc/boxed.rs b/src/liballoc/boxed.rs
index 2801cf38cb7..4468e425a85 100644
--- a/src/liballoc/boxed.rs
+++ b/src/liballoc/boxed.rs
@@ -275,6 +275,16 @@ impl<T: fmt::Debug + ?Sized> fmt::Debug for Box<T> {
     }
 }
 
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> fmt::Pointer for Box<T> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        // It's not possible to extract the inner Uniq directly from the Box,
+        // instead we cast it to a *const which aliases the Unique
+        let ptr: *const T = &**self;
+        fmt::Pointer::fmt(&ptr, f)
+    }
+}
+
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: ?Sized> Deref for Box<T> {
     type Target = T;
diff --git a/src/liballoc/rc.rs b/src/liballoc/rc.rs
index 56822cfe28a..67805d10a4a 100644
--- a/src/liballoc/rc.rs
+++ b/src/liballoc/rc.rs
@@ -634,6 +634,13 @@ impl<T: fmt::Debug> fmt::Debug for Rc<T> {
     }
 }
 
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> fmt::Pointer for Rc<T> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Pointer::fmt(&*self._ptr, f)
+    }
+}
+
 /// A weak version of `Rc<T>`.
 ///
 /// Weak references do not count when determining if the inner value should be
diff --git a/src/libcore/ptr.rs b/src/libcore/ptr.rs
index ff51e25fcbf..36b33e7581d 100644
--- a/src/libcore/ptr.rs
+++ b/src/libcore/ptr.rs
@@ -94,6 +94,7 @@ use mem;
 use clone::Clone;
 use intrinsics;
 use ops::Deref;
+use core::fmt;
 use option::Option::{self, Some, None};
 use marker::{PhantomData, Send, Sized, Sync};
 use nonzero::NonZero;
@@ -570,3 +571,10 @@ impl<T:?Sized> Deref for Unique<T> {
         unsafe { mem::transmute(&*self.pointer) }
     }
 }
+
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> fmt::Pointer for Unique<T> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Pointer::fmt(&*self.pointer, f)
+    }
+}
diff --git a/src/libsyntax/ptr.rs b/src/libsyntax/ptr.rs
index 7e0bcd3e1dc..5032cd57eeb 100644
--- a/src/libsyntax/ptr.rs
+++ b/src/libsyntax/ptr.rs
@@ -111,6 +111,13 @@ impl<T: Display> Display for P<T> {
     }
 }
 
+#[stable(feature = "rust1", since = "1.0.0")]
+impl<T> fmt::Pointer for P<T> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        fmt::Pointer::fmt(&self.ptr, f)
+    }
+}
+
 impl<T: Hash> Hash for P<T> {
     fn hash<H: Hasher>(&self, state: &mut H) {
         (**self).hash(state);
diff --git a/src/test/run-pass/fmt-pointer-trait.rs b/src/test/run-pass/fmt-pointer-trait.rs
new file mode 100644
index 00000000000..be8ecde6783
--- /dev/null
+++ b/src/test/run-pass/fmt-pointer-trait.rs
@@ -0,0 +1,28 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![feature(libc)]
+extern crate libc;
+use std::ptr;
+use std::rc::Rc;
+use std::sync::Arc;
+
+fn main() {
+    let p: *const libc::c_void = ptr::null();
+    let rc = Rc::new(1usize);
+    let arc = Arc::new(1usize);
+    let b = Box::new("hi");
+
+    let _ = format!("{:p}{:p}{:p}",
+                    rc, arc, b);
+
+    assert_eq!(format!("{:p}", p),
+               "0x0");
+}