diff --git a/src/libcore/ptr/unique.rs b/src/libcore/ptr/unique.rs
index 24f45394a3bd5..3521dd7997956 100644
--- a/src/libcore/ptr/unique.rs
+++ b/src/libcore/ptr/unique.rs
@@ -123,7 +123,7 @@ impl<T: ?Sized> Unique<T> {
         &mut *self.as_ptr()
     }
 
-    /// Casts to a pointer of another type
+    /// Casts to a pointer of another type.
     #[inline]
     pub const fn cast<U>(self) -> Unique<U> {
         unsafe {