Have serde::de::Error require std::error::Error

serde_tests/benches/bench_struct.rs

@@ -1,5 +1,7 @@
 use std::collections::HashMap;
 use test::Bencher;
+use std::fmt;
+use std::error;
 
 use rustc_serialize::{Decoder, Decodable};
 
@@ -44,6 +46,22 @@ impl serde::de::Error for Error {
     }
 }
 
+impl fmt::Display for Error {
+    fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        formatter.write_str(format!("{:?}", self).as_ref())
+    }
+}
+
+impl error::Error for Error {
+    fn description(&self) -> &str {
+        "Serde Deserialization Error"
+    }
+
+    fn cause(&self) -> Option<&error::Error> {
+        None
+    }
+}
+
 mod decoder {
     use std::collections::HashMap;
     use rustc_serialize::Decoder;