From 9c2f1dd377d5bfa6ff7d122bb6ec5f2443bd5aa4 Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume1.gomez@gmail.com>
Date: Wed, 16 Oct 2019 13:29:30 +0200
Subject: [PATCH 1/2] Add long error explanation for E0578

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

diff --git a/src/librustc_resolve/error_codes.rs b/src/librustc_resolve/error_codes.rs
index b14913cd4fdde..c59959ae4f4c5 100644
--- a/src/librustc_resolve/error_codes.rs
+++ b/src/librustc_resolve/error_codes.rs
@@ -1850,6 +1850,34 @@ fn main() {}
 ```
 "##,
 
+E0578: r##"
+A module cannot be found and therefore, the visibility cannot be determined.
+
+Erroneous code example:
+
+```compile_fail,E0578,edition2018
+foo!();
+
+pub (in ::Sea) struct Shark; // error!
+
+fn main() {}
+```
+
+Because of the call to the `foo` macro, the compiler guesses that the missing
+module could be inside it and fails because the macro definition cannot be
+found.
+
+To fix this error, please be sure that the module is in scope:
+
+```edition2018
+pub mod Sea {
+    pub (in crate::Sea) struct Shark;
+}
+
+fn main() {}
+```
+"##,
+
 E0603: r##"
 A private item was used outside its scope.
 
@@ -2017,5 +2045,4 @@ fn main() {}
 //  E0427, merged into 530
 //  E0467, removed
 //  E0470, removed
-    E0578,
 }

From bfe9c9e42974d8deda4abf2027c868120004d853 Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume1.gomez@gmail.com>
Date: Wed, 16 Oct 2019 13:29:43 +0200
Subject: [PATCH 2/2] update ui tests

---
 src/test/ui/resolve/visibility-indeterminate.stderr | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/test/ui/resolve/visibility-indeterminate.stderr b/src/test/ui/resolve/visibility-indeterminate.stderr
index b9678291ee40b..84d82ce852240 100644
--- a/src/test/ui/resolve/visibility-indeterminate.stderr
+++ b/src/test/ui/resolve/visibility-indeterminate.stderr
@@ -12,3 +12,4 @@ LL | foo!();
 
 error: aborting due to 2 previous errors
 
+For more information about this error, try `rustc --explain E0578`.