From 61d92a09529818bdd3ed832a7e2fdd6394c358bf Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume1.gomez@gmail.com>
Date: Mon, 7 Oct 2019 12:59:39 +0200
Subject: [PATCH 1/2] Add long error explanation for E0567

---
 src/librustc_passes/error_codes.rs | 29 ++++++++++++++++++++++++++++-
 1 file changed, 28 insertions(+), 1 deletion(-)

diff --git a/src/librustc_passes/error_codes.rs b/src/librustc_passes/error_codes.rs
index a3c46f7a6fc9d..fbd06c34800df 100644
--- a/src/librustc_passes/error_codes.rs
+++ b/src/librustc_passes/error_codes.rs
@@ -314,6 +314,34 @@ type A3 = fn(i16); // ok!
 ```
 "##,
 
+E0567: r##"
+Generics have been used on an auto trait.
+
+Erroneous code example:
+
+```compile_fail,E0567
+#![feature(optin_builtin_traits)]
+
+auto trait Generic<T> {} // error!
+
+fn main() {}
+```
+
+Since an auto trait is implemented on all existing types, the
+compiler would not be able to infer the types of the trait's generic
+parameters.
+
+To fix this issue, just remove the generics:
+
+```
+#![feature(optin_builtin_traits)]
+
+auto trait Generic {} // ok!
+
+fn main() {}
+```
+"##,
+
 E0571: r##"
 A `break` statement with an argument appeared in a non-`loop` loop.
 
@@ -531,7 +559,6 @@ Switch to the Rust 2018 edition to use `async fn`.
 ;
     E0226, // only a single explicit lifetime bound is permitted
     E0472, // asm! is unsupported on this target
-    E0567, // auto traits can not have generic parameters
     E0568, // auto traits can not have super traits
     E0666, // nested `impl Trait` is illegal
     E0667, // `impl Trait` in projections

From 6608e4af1bd80f096f1f52c118e856d23498c787 Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume1.gomez@gmail.com>
Date: Mon, 7 Oct 2019 14:08:26 +0200
Subject: [PATCH 2/2] Update ui tests

---
 src/test/ui/auto-trait-validation.stderr | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/test/ui/auto-trait-validation.stderr b/src/test/ui/auto-trait-validation.stderr
index ae21984c06d72..d797f30a2fc8c 100644
--- a/src/test/ui/auto-trait-validation.stderr
+++ b/src/test/ui/auto-trait-validation.stderr
@@ -18,4 +18,5 @@ LL | auto trait MyTrait { fn foo() {} }
 
 error: aborting due to 3 previous errors
 
-For more information about this error, try `rustc --explain E0380`.
+Some errors have detailed explanations: E0380, E0567.
+For more information about an error, try `rustc --explain E0380`.