From 4cd92768ee9cbaf0df98f0d31f0c44e62f63d79a Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume1.gomez@gmail.com>
Date: Thu, 17 Oct 2019 11:06:06 +0200
Subject: [PATCH 1/2] Add long error explanation for E0584

---
 src/libsyntax/error_codes.rs | 28 +++++++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

diff --git a/src/libsyntax/error_codes.rs b/src/libsyntax/error_codes.rs
index fc3f095856a80..17ea476752064 100644
--- a/src/libsyntax/error_codes.rs
+++ b/src/libsyntax/error_codes.rs
@@ -295,6 +295,33 @@ named `file_that_doesnt_exist.rs` or `file_that_doesnt_exist/mod.rs` in the
 same directory.
 "##,
 
+E0584: r##"
+A doc comment that is not attached to anything has been encountered.
+
+Erroneous code example:
+
+```compile_fail,E0584
+trait Island {
+    fn lost();
+
+    /// I'm lost!
+}
+```
+
+A little reminder: a doc comment has to be placed before the item it's supposed
+to document. So if you want to document the `Island` trait, you need to put a
+doc comment before it, not inside it. Same goes for the `lost` method: the doc
+comment needs to be before it:
+
+```
+/// I'm THE island!
+trait Island {
+    /// I'm lost!
+    fn lost();
+}
+```
+"##,
+
 E0585: r##"
 A documentation comment that doesn't document anything was found.
 
@@ -494,7 +521,6 @@ features in the `-Z allow_features` flag.
     E0549,
     E0553, // multiple rustc_const_unstable attributes
 //  E0555, // replaced with a generic attribute input check
-    E0584, // file for module `..` found at both .. and ..
     E0629, // missing 'feature' (rustc_const_unstable)
     // rustc_const_unstable attribute must be paired with stable/unstable
     // attribute

From f647c06120150bb26c843a5eaa65caf5c336b51a Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume1.gomez@gmail.com>
Date: Thu, 17 Oct 2019 11:06:14 +0200
Subject: [PATCH 2/2] Update ui tests

---
 src/test/ui/mod/mod_file_disambig.stderr        | 1 +
 src/test/ui/parser/doc-inside-trait-item.stderr | 1 +
 2 files changed, 2 insertions(+)

diff --git a/src/test/ui/mod/mod_file_disambig.stderr b/src/test/ui/mod/mod_file_disambig.stderr
index 27df0241aa21f..2b77d866fb30b 100644
--- a/src/test/ui/mod/mod_file_disambig.stderr
+++ b/src/test/ui/mod/mod_file_disambig.stderr
@@ -8,3 +8,4 @@ LL | mod mod_file_disambig_aux;
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0584`.
diff --git a/src/test/ui/parser/doc-inside-trait-item.stderr b/src/test/ui/parser/doc-inside-trait-item.stderr
index 3287ece9ae644..261e27b6e0d18 100644
--- a/src/test/ui/parser/doc-inside-trait-item.stderr
+++ b/src/test/ui/parser/doc-inside-trait-item.stderr
@@ -8,3 +8,4 @@ LL |     /// empty doc
 
 error: aborting due to previous error
 
+For more information about this error, try `rustc --explain E0584`.