From def04dedc157aa5f6880b21662b06b747a7c10bb Mon Sep 17 00:00:00 2001
From: David Tolnay <dtolnay@gmail.com>
Date: Wed, 22 Jan 2020 00:02:25 -0800
Subject: [PATCH] Remove source method in no_std mode

An io error can never occur in no_std mode so the source method is never
applicable.
---
 src/error.rs   | 3 ++-
 src/io/core.rs | 2 --
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/error.rs b/src/error.rs
index b8f0356..6cacba6 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -334,7 +334,8 @@ impl Display for ErrorCode {
 }
 
 impl serde::de::StdError for Error {
-    fn source(&self) -> Option<&(serde::de::StdError + 'static)> {
+    #[cfg(feature = "std")]
+    fn source(&self) -> Option<&(error::Error + 'static)> {
         match self.err.code {
             ErrorCode::Io(ref err) => Some(err),
             _ => None,
diff --git a/src/io/core.rs b/src/io/core.rs
index f83f5cf..5ffea38 100644
--- a/src/io/core.rs
+++ b/src/io/core.rs
@@ -22,8 +22,6 @@ impl Debug for Error {
     }
 }
 
-impl serde::de::StdError for Error {}
-
 impl Error {
     pub(crate) fn new(kind: ErrorKind, error: &'static str) -> Error {
         let _ = kind;