From 778d5f2074b05c013e15fabc25daf4e37a174bf7 Mon Sep 17 00:00:00 2001
From: Clar Charr <clar@charr.xyz>
Date: Sat, 9 Sep 2017 16:48:40 -0400
Subject: [PATCH] Add Cow<str> -> Box<Error> impls.

---
 src/libstd/error.rs | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/src/libstd/error.rs b/src/libstd/error.rs
index 401552a6ec4..6d64ea0d503 100644
--- a/src/libstd/error.rs
+++ b/src/libstd/error.rs
@@ -53,6 +53,7 @@
 
 use alloc::allocator;
 use any::TypeId;
+use borrow::Cow;
 use cell;
 use char;
 use fmt::{self, Debug, Display};
@@ -217,6 +218,20 @@ impl<'a> From<&'a str> for Box<Error> {
     }
 }
 
+#[stable(feature = "cow_box_error", since = "1.22.0")]
+impl<'a, 'b> From<Cow<'b, str>> for Box<Error + Send + Sync + 'a> {
+    fn from(err: Cow<'b, str>) -> Box<Error + Send + Sync + 'a> {
+        From::from(String::from(err))
+    }
+}
+
+#[stable(feature = "cow_box_error", since = "1.22.0")]
+impl<'a> From<Cow<'a, str>> for Box<Error> {
+    fn from(err: Cow<'a, str>) -> Box<Error> {
+        From::from(String::from(err))
+    }
+}
+
 #[unstable(feature = "never_type_impls", issue = "35121")]
 impl Error for ! {
     fn description(&self) -> &str { *self }