From b61d9faece1c764a2a6ce4fd3170e2b3b1a678db Mon Sep 17 00:00:00 2001
From: Toralf Wittner <tw@dtex.org>
Date: Fri, 21 Sep 2018 10:39:36 +0200
Subject: [PATCH] multiaddr: future-proof error type (#506)

---
 misc/multiaddr/src/errors.rs   | 7 +++++--
 misc/multiaddr/src/protocol.rs | 4 ++--
 2 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/misc/multiaddr/src/errors.rs b/misc/multiaddr/src/errors.rs
index b404c7eb..44cb01b0 100644
--- a/misc/multiaddr/src/errors.rs
+++ b/misc/multiaddr/src/errors.rs
@@ -15,7 +15,9 @@ pub enum Error {
     InvalidUvar(decode::Error),
     ParsingError(Box<dyn error::Error + Send + Sync>),
     UnknownProtocolId(u32),
-    UnknownProtocolString
+    UnknownProtocolString,
+    #[doc(hidden)]
+    __Nonexhaustive
 }
 
 impl fmt::Display for Error {
@@ -27,7 +29,8 @@ impl fmt::Display for Error {
             Error::InvalidUvar(e) => write!(f, "failed to decode unsigned varint: {}", e),
             Error::ParsingError(e) => write!(f, "failed to parse: {}", e),
             Error::UnknownProtocolId(id) => write!(f, "unknown protocol id: {}", id),
-            Error::UnknownProtocolString => f.write_str("unknown protocol string")
+            Error::UnknownProtocolString => f.write_str("unknown protocol string"),
+            Error::__Nonexhaustive => f.write_str("__Nonexhaustive")
         }
     }
 }
diff --git a/misc/multiaddr/src/protocol.rs b/misc/multiaddr/src/protocol.rs
index e4a99018..a610cd4d 100644
--- a/misc/multiaddr/src/protocol.rs
+++ b/misc/multiaddr/src/protocol.rs
@@ -5,7 +5,7 @@ use std::{
     borrow::Cow,
     convert::From,
     fmt,
-    io::{self, Cursor, Write},
+    io::{Cursor, Write},
     net::{Ipv4Addr, Ipv6Addr},
     str::{self, FromStr}
 };
@@ -232,7 +232,7 @@ impl<'a> Protocol<'a> {
 
     /// Encode this protocol by writing its binary representation into
     /// the given `Write` impl.
-    pub fn write_bytes<W: Write>(&self, w: &mut W) -> io::Result<()> {
+    pub fn write_bytes<W: Write>(&self, w: &mut W) -> Result<()> {
         let mut buf = encode::u32_buffer();
         match self {
             Protocol::Ip4(addr) => {