From c745b4a1841bc5bea8dd50cad85921b36ca47242 Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume1.gomez@gmail.com>
Date: Wed, 4 Mar 2020 13:01:19 +0100
Subject: [PATCH] Add explanation for E0380

---
 src/librustc_error_codes/error_codes/E0380.md | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/src/librustc_error_codes/error_codes/E0380.md b/src/librustc_error_codes/error_codes/E0380.md
index fe5de56933963..638f0c8ecc65f 100644
--- a/src/librustc_error_codes/error_codes/E0380.md
+++ b/src/librustc_error_codes/error_codes/E0380.md
@@ -1,4 +1,14 @@
-Auto traits cannot have methods or associated items.
-For more information see the [opt-in builtin traits RFC][RFC 19].
+An auto trait was declared with a method or an associated item.
+
+Erroneous code example:
+
+```compile_fail,E0380
+unsafe auto trait Trait {
+    type Output; // error!
+}
+```
+
+Auto traits cannot have methods or associated items. For more information see
+the [opt-in builtin traits RFC][RFC 19].
 
 [RFC 19]: https://github.com/rust-lang/rfcs/blob/master/text/0019-opt-in-builtin-traits.md