Add conversions from references to NonZero pointers, Unique, and Shared

Author: SimonSapin

src/liballoc/btree/node.rs

@@ -155,7 +155,7 @@ impl<K, V> BoxedNode<K, V> {
 
     fn as_ptr(&self) -> NonZero<*const LeafNode<K, V>> {
         unsafe {
-            NonZero::new_unchecked(self.ptr.as_ptr())
+            NonZero::from(self.ptr.as_ref())
         }
     }
 }

src/liballoc/vec.rs

@@ -1126,7 +1126,7 @@ impl<T> Vec<T> {
                 tail_start: end,
                 tail_len: len - end,
                 iter: range_slice.iter(),
-                vec: Shared::new_unchecked(self as *mut _),
+                vec: Shared::from(self),
             }
         }
     }

src/liballoc/vec_deque.rs

@@ -893,7 +893,7 @@ impl<T> VecDeque<T> {
         self.head = drain_tail;
 
         Drain {
-            deque: unsafe { Shared::new_unchecked(self as *mut _) },
+            deque: Shared::from(&mut *self),
             after_tail: drain_head,
             after_head: head,
             iter: Iter {

src/libcore/nonzero.rs

@@ -90,3 +90,22 @@ impl<T: Zeroable> NonZero<T> {
 }
 
 impl<T: Zeroable+CoerceUnsized<U>, U: Zeroable> CoerceUnsized<NonZero<U>> for NonZero<T> {}
+
+impl<'a, T: ?Sized> From<&'a mut T> for NonZero<*mut T> {
+    fn from(reference: &'a mut T) -> Self {
+        NonZero(reference)
+    }
+}
+
+impl<'a, T: ?Sized> From<&'a mut T> for NonZero<*const T> {
+    fn from(reference: &'a mut T) -> Self {
+        let ptr: *mut T = reference;
+        NonZero(ptr)
+    }
+}
+
+impl<'a, T: ?Sized> From<&'a T> for NonZero<*const T> {
+    fn from(reference: &'a T) -> Self {
+        NonZero(reference)
+    }
+}

src/libcore/ptr.rs

@@ -1164,6 +1164,20 @@ impl<T: ?Sized> fmt::Pointer for Unique<T> {
     }
 }
 
+#[unstable(feature = "unique", issue = "27730")]
+impl<'a, T: ?Sized> From<&'a mut T> for Unique<T> {
+    fn from(reference: &'a mut T) -> Self {
+        Unique { pointer: NonZero::from(reference), _marker: PhantomData }
+    }
+}
+
+#[unstable(feature = "unique", issue = "27730")]
+impl<'a, T: ?Sized> From<&'a T> for Unique<T> {
+    fn from(reference: &'a T) -> Self {
+        Unique { pointer: NonZero::from(reference), _marker: PhantomData }
+    }
+}
+
 /// A wrapper around a raw `*mut T` that indicates that the possessor
 /// of this wrapper has shared ownership of the referent. Useful for
 /// building abstractions like `Rc<T>`, `Arc<T>`, or doubly-linked lists, which
@@ -1296,3 +1310,17 @@ impl<T: ?Sized> From<Unique<T>> for Shared<T> {
         Shared { pointer: unique.pointer, _marker: PhantomData }
     }
 }
+
+#[unstable(feature = "shared", issue = "27730")]
+impl<'a, T: ?Sized> From<&'a mut T> for Shared<T> {
+    fn from(reference: &'a mut T) -> Self {
+        Shared { pointer: NonZero::from(reference), _marker: PhantomData }
+    }
+}
+
+#[unstable(feature = "shared", issue = "27730")]
+impl<'a, T: ?Sized> From<&'a T> for Shared<T> {
+    fn from(reference: &'a T) -> Self {
+        Shared { pointer: NonZero::from(reference), _marker: PhantomData }
+    }
+}

src/librustc_data_structures/array_vec.rs

@@ -146,7 +146,7 @@ impl<A: Array> ArrayVec<A> {
                 tail_start: end,
                 tail_len: len - end,
                 iter: range_slice.iter(),
-                array_vec: Shared::new_unchecked(self as *mut _),
+                array_vec: Shared::from(self),
             }
         }
     }

src/libstd/collections/hash/table.rs

@@ -877,7 +877,7 @@ impl<K, V> RawTable<K, V> {
                 elems_left: elems_left,
                 marker: marker::PhantomData,
             },
-            table: unsafe { Shared::new_unchecked(self) },
+            table: Shared::from(self),
             marker: marker::PhantomData,
         }
     }