From 50de2dacb3d2223672a0d946830daac7de8f67a1 Mon Sep 17 00:00:00 2001
From: Matthew Scheirer <matt.scheirer@gmail.com>
Date: Sun, 17 Sep 2017 18:59:06 -0400
Subject: [PATCH] impl error::cause

---
 src/error.rs | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/error.rs b/src/error.rs
index c25a4e3..00be9cc 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -71,7 +71,18 @@ impl ErrorTrait for Error {
     }
 
     fn cause(&self) -> Option<&ErrorTrait> {
-        unimplemented!()
+        use Error::*;
+        match *self {
+            Jose(ref err)       => Some(err),
+            Json(ref err)       => Some(err),
+            Oauth(ref err)      => Some(err),
+            Reqwest(ref err)    => Some(err),
+            Decode(ref err)     => None,
+            Validation(ref err) => None,
+            Userinfo(ref err)   => None,
+            Insecure(_)         => None,
+            MissingOpenidScope  => None,
+        }
     }
 }