From 792dc8d067d1f11e08e859ccdd45d59436773fc9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marvin=20L=C3=B6bel?= <loebel.marvin@gmail.com>
Date: Tue, 10 Feb 2015 14:37:44 +0100
Subject: [PATCH] Made the `ptr::Unique` type accept unsized types, to allow
 for use cases like sending a raw pointer slice across thread boundaries.

---
 src/libcore/ptr.rs     | 6 +++---
 src/libcoretest/ptr.rs | 9 +++++++++
 2 files changed, 12 insertions(+), 3 deletions(-)

diff --git a/src/libcore/ptr.rs b/src/libcore/ptr.rs
index ba1eae551ff2a..bf801a88ca5b3 100644
--- a/src/libcore/ptr.rs
+++ b/src/libcore/ptr.rs
@@ -522,21 +522,21 @@ impl<T> PartialOrd for *mut T {
 /// Useful for building abstractions like `Vec<T>` or `Box<T>`, which
 /// internally use raw pointers to manage the memory that they own.
 #[unstable(feature = "core", reason = "recently added to this module")]
-pub struct Unique<T>(pub *mut T);
+pub struct Unique<T: ?Sized>(pub *mut T);
 
 /// `Unique` pointers are `Send` if `T` is `Send` because the data they
 /// reference is unaliased. Note that this aliasing invariant is
 /// unenforced by the type system; the abstraction using the
 /// `Unique` must enforce it.
 #[unstable(feature = "core", reason = "recently added to this module")]
-unsafe impl<T:Send> Send for Unique<T> { }
+unsafe impl<T: Send + ?Sized> Send for Unique<T> { }
 
 /// `Unique` pointers are `Sync` if `T` is `Sync` because the data they
 /// reference is unaliased. Note that this aliasing invariant is
 /// unenforced by the type system; the abstraction using the
 /// `Unique` must enforce it.
 #[unstable(feature = "core", reason = "recently added to this module")]
-unsafe impl<T:Sync> Sync for Unique<T> { }
+unsafe impl<T: Sync + ?Sized> Sync for Unique<T> { }
 
 impl<T> Unique<T> {
     /// Returns a null Unique.
diff --git a/src/libcoretest/ptr.rs b/src/libcoretest/ptr.rs
index 7f0b97c53d465..2365b907b3ff5 100644
--- a/src/libcoretest/ptr.rs
+++ b/src/libcoretest/ptr.rs
@@ -167,3 +167,12 @@ fn test_set_memory() {
     unsafe { set_memory(ptr, 5u8, xs.len()); }
     assert!(xs == [5u8; 20]);
 }
+
+#[test]
+fn test_unsized_unique() {
+    let xs: &mut [_] = &mut [1, 2, 3];
+    let ptr = Unique(xs as *mut [_]);
+    let ys = unsafe { &mut *ptr.0 };
+    let zs: &mut [_] = &mut [1, 2, 3];
+    assert!(ys == zs);
+}