diff --git a/src/libcore/ptr.rs b/src/libcore/ptr.rs
index 5a54de06b5ef2..a1307a6d5996e 100644
--- a/src/libcore/ptr.rs
+++ b/src/libcore/ptr.rs
@@ -2511,6 +2511,7 @@ impl<T: ?Sized> PartialOrd for *mut T {
            reason = "use NonNull instead and consider PhantomData<T> \
                      (if you also use #[may_dangle]), Send, and/or Sync")]
 #[allow(deprecated)]
+#[doc(hidden)]
 pub struct Unique<T: ?Sized> {
     pointer: NonZero<*const T>,
     // NOTE: this marker has no consequences for variance, but is necessary