From 45748256ef51ae1fcd6bb033d057dc46756ebb4f Mon Sep 17 00:00:00 2001
From: Havvy <ryan.havvy@gmail.com>
Date: Mon, 11 Jun 2018 13:26:03 -0700
Subject: [PATCH 1/2] Long diagnostic for E0538

---
 src/libsyntax/diagnostic_list.rs | 31 ++++++++++++++++++++++++++++++-
 1 file changed, 30 insertions(+), 1 deletion(-)

diff --git a/src/libsyntax/diagnostic_list.rs b/src/libsyntax/diagnostic_list.rs
index 9775a6475ccd6..1c78cac6b70f2 100644
--- a/src/libsyntax/diagnostic_list.rs
+++ b/src/libsyntax/diagnostic_list.rs
@@ -93,6 +93,36 @@ For more information about the cfg attribute, read:
 https://doc.rust-lang.org/reference.html#conditional-compilation
 "##,
 
+E0538: r##"
+Attribute contains multiple of the same meta item.
+
+Erroneous code example:
+
+```compile_fail,E0538
+#[deprecated(
+    since="1.0.0",
+    note="First deprecation note.",
+    note="Second deprecation note." // error: multiple same meta item
+)]
+fn deprecated_function() {}
+```
+
+Meta items are the key-value pairs inside of an attribute. Each key may only be
+used once in each attribute.
+
+To fix the problem, remove all but one of the meta items with the same key.
+
+Example:
+
+```
+#[deprecated(
+    since="1.0.0",
+    note="First deprecation note."
+)]
+fn deprecated_function() {}
+```
+"##,
+
 E0541: r##"
 An unknown meta item was used.
 
@@ -347,7 +377,6 @@ and likely to change in the future.
 }
 
 register_diagnostics! {
-    E0538, // multiple [same] items
     E0539, // incorrect meta item
     E0540, // multiple rustc_deprecated attributes
     E0542, // missing 'since'

From e9e0ca0382e9e5da4db89f22ec0de15dbd966d32 Mon Sep 17 00:00:00 2001
From: Havvy <ryan.havvy@gmail.com>
Date: Mon, 11 Jun 2018 17:21:15 -0700
Subject: [PATCH 2/2] Slightly better summary for E0538

---
 src/libsyntax/diagnostic_list.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/libsyntax/diagnostic_list.rs b/src/libsyntax/diagnostic_list.rs
index 1c78cac6b70f2..ab8317bfa027e 100644
--- a/src/libsyntax/diagnostic_list.rs
+++ b/src/libsyntax/diagnostic_list.rs
@@ -94,7 +94,7 @@ https://doc.rust-lang.org/reference.html#conditional-compilation
 "##,
 
 E0538: r##"
-Attribute contains multiple of the same meta item.
+Attribute contains same meta item more than once.
 
 Erroneous code example: