3 files changed, 4 insertions, 0 deletions
diff --git a/src/liballoc/arc.rs b/src/liballoc/arc.rs
index b54b71cabd1..3d579641b96 100644
--- a/src/liballoc/arc.rs
+++ b/src/liballoc/arc.rs
@@ -718,6 +718,7 @@ impl<T: ?Sized> Clone for Weak<T> {
 
 #[stable(feature = "downgraded_weak", since = "1.10.0")]
 impl<T> Default for Weak<T> {
+    /// Constructs a new `Weak<T>` without an accompanying instance of T.
     fn default() -> Weak<T> {
         Weak::new()
     }
@@ -923,6 +924,7 @@ impl<T: ?Sized> fmt::Pointer for Arc<T> {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: Default> Default for Arc<T> {
+    /// Creates a new `Arc<T>`, with the `Default` value for T.
     fn default() -> Arc<T> {
         Arc::new(Default::default())
     }
diff --git a/src/liballoc/boxed.rs b/src/liballoc/boxed.rs
index 70c429cc360..bc9b6e805ef 100644
--- a/src/liballoc/boxed.rs
+++ b/src/liballoc/boxed.rs
@@ -290,6 +290,7 @@ impl<T: ?Sized> Box<T> {
 
 #[stable(feature = "rust1", since = "1.0.0")]
 impl<T: Default> Default for Box<T> {
+    /// Creates a `Box<T>`, with the `Default` value for T.
     fn default() -> Box<T> {
         box Default::default()
     }
diff --git a/src/liballoc/rc.rs b/src/liballoc/rc.rs
index c24c7ca47ad..dadddbc2cb3 100644
--- a/src/liballoc/rc.rs
+++ b/src/liballoc/rc.rs
@@ -870,6 +870,7 @@ impl<T: ?Sized + fmt::Debug> fmt::Debug for Weak<T> {
 
 #[stable(feature = "downgraded_weak", since = "1.10.0")]
 impl<T> Default for Weak<T> {
+    /// Creates a new `Weak<T>`.
     fn default() -> Weak<T> {
         Weak::new()
     }