Rollup merge of #69340 - Centril:self-ctor-normalize, r=nikomatsakis

[rust.git] / src / libcore / marker.rs

diff --git a/src/libcore/marker.rs b/src/libcore/marker.rs
index b4b595f330e22ac556e6c245819d91c7536e7b65..2800f11cc01b1ae43600b4e82df2ceac154050e8 100644 (file)
--- a/src/libcore/marker.rs
+++ b/src/libcore/marker.rs
@@ -727,6 +727,10 @@ unsafe impl<T: ?Sized> Freeze for &mut T {}
 /// [`Pin<P>`]: ../pin/struct.Pin.html
 /// [`pin module`]: ../../std/pin/index.html
 #[stable(feature = "pin", since = "1.33.0")]
+#[rustc_on_unimplemented(
+    on(_Self = "std::future::Future", note = "consider using `Box::pin`",),
+    message = "`{Self}` cannot be unpinned"
+)]
 #[lang = "unpin"]
 pub auto trait Unpin {}