From 8e352f7d866f46e09746d7f8557818984a1f3854 Mon Sep 17 00:00:00 2001
From: Sam Whited <sam@samwhited.com>
Date: Tue, 21 Mar 2017 20:15:55 -0500
Subject: [PATCH 1/2] E0090: Add explanation for error message

See #32777
---
 src/librustc_typeck/diagnostics.rs | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/librustc_typeck/diagnostics.rs b/src/librustc_typeck/diagnostics.rs
index 644e323a8dbf2..2d24b1fb4f20a 100644
--- a/src/librustc_typeck/diagnostics.rs
+++ b/src/librustc_typeck/diagnostics.rs
@@ -1223,6 +1223,18 @@ fn main() {
 ```
 "##,
 
+E0090: r##"
+The wrong number of lifetimes were supplied. For example:
+
+```compile_fail,E0090
+fn foo<'a: 'b, 'b: 'a>() {}
+
+fn main() {
+    foo::<'static>(); // error, expected 2 lifetime parameters
+}
+```
+"##,
+
 E0091: r##"
 You gave an unnecessary type parameter in a type alias. Erroneous code
 example:
@@ -4120,7 +4132,6 @@ register_diagnostics! {
 //  E0068,
 //  E0085,
 //  E0086,
-    E0090,
     E0103, // @GuillaumeGomez: I was unable to get this error, try your best!
     E0104,
 //  E0123,

From 8ea0f18d9a3bdf001be8d668818b8291dd2b37df Mon Sep 17 00:00:00 2001
From: Sam Whited <sam@samwhited.com>
Date: Wed, 22 Mar 2017 00:07:12 -0500
Subject: [PATCH 2/2] E0090: Expand error message explanation

---
 src/librustc_typeck/diagnostics.rs | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/librustc_typeck/diagnostics.rs b/src/librustc_typeck/diagnostics.rs
index 2d24b1fb4f20a..0136faef28d8c 100644
--- a/src/librustc_typeck/diagnostics.rs
+++ b/src/librustc_typeck/diagnostics.rs
@@ -1224,7 +1224,7 @@ fn main() {
 "##,
 
 E0090: r##"
-The wrong number of lifetimes were supplied. For example:
+You gave too few lifetime parameters. Example:
 
 ```compile_fail,E0090
 fn foo<'a: 'b, 'b: 'a>() {}
@@ -1233,6 +1233,16 @@ fn main() {
     foo::<'static>(); // error, expected 2 lifetime parameters
 }
 ```
+
+Please check you give the right number of lifetime parameters. Example:
+
+```
+fn foo<'a: 'b, 'b: 'a>() {}
+
+fn main() {
+    foo::<'static, 'static>();
+}
+```
 "##,
 
 E0091: r##"