From c911bb1a2e5efc35a8e76bfe6e2581f4a9dfc20b Mon Sep 17 00:00:00 2001
From: Guillaume Gomez <guillaume1.gomez@gmail.com>
Date: Sat, 30 Nov 2019 13:42:50 +0100
Subject: [PATCH] clean up E0107 error explanation

---
 src/librustc_error_codes/error_codes/E0107.md | 23 ++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/src/librustc_error_codes/error_codes/E0107.md b/src/librustc_error_codes/error_codes/E0107.md
index bfe0d21f312..4d22b17fe10 100644
--- a/src/librustc_error_codes/error_codes/E0107.md
+++ b/src/librustc_error_codes/error_codes/E0107.md
@@ -1,4 +1,6 @@
-This error means that an incorrect number of generic arguments were provided:
+An incorrect number of generic arguments were provided.
+
+Erroneous code example:
 
 ```compile_fail,E0107
 struct Foo<T> { x: T }
@@ -9,6 +11,7 @@ struct Baz<S, T> { x: Foo<S, T> } // error: wrong number of type arguments:
                                   //        expected 1, found 2
 
 fn foo<T, U>(x: T, y: U) {}
+fn f() {}
 
 fn main() {
     let x: bool = true;
@@ -16,12 +19,26 @@ fn main() {
                                     //        expected 2, found 1
     foo::<bool, i32, i32>(x, 2, 4); // error: wrong number of type arguments:
                                     //        expected 2, found 3
+    f::<'static>();                 // error: wrong number of lifetime arguments
+                                    //        expected 0, found 1
 }
+```
 
+When using/declaring an item with generic arguments, you must provide the exact
+same number:
+
+```
+struct Foo<T> { x: T }
+
+struct Bar<T> { x: Foo<T> }               // ok!
+struct Baz<S, T> { x: Foo<S>, y: Foo<T> } // ok!
+
+fn foo<T, U>(x: T, y: U) {}
 fn f() {}
 
 fn main() {
-    f::<'static>(); // error: wrong number of lifetime arguments:
-                    //        expected 0, found 1
+    let x: bool = true;
+    foo::<bool, u32>(x, 12);              // ok!
+    f();                                  // ok!
 }
 ```