From f9f29814e3451757b254121115c9bb9f4a3fc253 Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume1.gomez@gmail.com>
Date: Sat, 9 Jan 2016 18:19:20 +0100
Subject: [PATCH] Impl Error for Box<T: Error>

---
 src/libstd/error.rs | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/src/libstd/error.rs b/src/libstd/error.rs
index ee367193e456..660948b0acca 100644
--- a/src/libstd/error.rs
+++ b/src/libstd/error.rs
@@ -189,6 +189,17 @@ impl Error for string::ParseError {
     }
 }
 
+#[stable(feature = "box_error", since = "1.7.0")]
+impl<T: Error> Error for Box<T> {
+    fn description(&self) -> &str {
+        Error::description(&**self)
+    }
+
+    fn cause(&self) -> Option<&Error> {
+        Error::cause(&**self)
+    }
+}
+
 // copied from any.rs
 impl Error + 'static {
     /// Returns true if the boxed type is the same as `T`