Rollup merge of #56939 - cramertj:pin-stabilization, r=alexcrichton

Pin stabilization

This implements the changes suggested in https://github.com/rust-lang/rust/issues/55766#issue-378417538 and stabilizes the `pin` feature. @alexcrichton also listed several "blockers" in that issue, but then in [this comment](https://github.com/rust-lang/rust/issues/55766#issuecomment-445074980) mentioned that they're more "TODO items":
>  In that vein I think it's fine for a stabilization PR to be posted at any time now with FCP lapsed for a week or so now. The final points about self/pin/pinned can be briefly discussed there (if even necessary, they could be left as the proposal above).

Let's settle these last bits here and get this thing stabilized! :)

r? @alexcrichton
cc @withoutboats

1 files changed, 5 insertions, 3 deletions

diff --git a/src/liballoc/sync.rs b/src/liballoc/sync.rs
index 948c36117a3..7b8afb1943c 100644
--- a/src/liballoc/sync.rs
+++ b/src/liballoc/sync.rs
@@ -303,8 +303,10 @@ impl<T> Arc<T> {
         Arc { ptr: Box::into_raw_non_null(x), phantom: PhantomData }
     }
 
-    #[unstable(feature = "pin", issue = "49150")]
-    pub fn pinned(data: T) -> Pin<Arc<T>> {
+    /// Constructs a new `Pin<Arc<T>>`. If `T` does not implement `Unpin`, then
+    /// `data` will be pinned in memory and unable to be moved.
+    #[stable(feature = "pin", since = "1.33.0")]
+    pub fn pin(data: T) -> Pin<Arc<T>> {
         unsafe { Pin::new_unchecked(Arc::new(data)) }
     }
 
@@ -2050,5 +2052,5 @@ impl<T: ?Sized> AsRef<T> for Arc<T> {
     }
 }
 
-#[unstable(feature = "pin", issue = "49150")]
+#[stable(feature = "pin", since = "1.33.0")]
 impl<T: ?Sized> Unpin for Arc<T> { }