Add long diagnostics for "bind by-ref and by-move"

Author: GuillaumeGomez

src/librustc/diagnostics.rs

@@ -112,6 +112,40 @@ reference when using guards or refactor the entire expression, perhaps by
 putting the condition inside the body of the arm.
 "##,
 
+E0009: r##"
+In a pattern, all values that don't implement the Copy trait have to be binded the same way
+than the others. The goal here is to avoid to bind by-move and by-ref at the same time.
+Wrong example:
+struct X { x: (), }
+
+let x = Some((X { x: () }, X { x: () }));
+match x {
+    Some((_y, ref _z)) => {},
+    None => panic!()
+}
+
+You have two solutions:
+* implement the Copy trait on the X structure:
+#[derive(Clone, Copy)]
+struct X { x: (), }
+
+let x = Some((X { x: () }, X { x: () }));
+match x {
+    Some((_y, ref _z)) => {},
+    None => panic!()
+}
+
+* bind the the pattern's values the same way:
+struct X { x: (), }
+
+let x = Some((X { x: () }, X { x: () }));
+match x {
+    Some((ref _y, ref _z)) => {},
+    // or Some((_y, _z)) => {}
+    None => panic!()
+}
+"##,
+
 E0162: r##"
 An if-let pattern attempts to match the pattern, and enters the body if the
 match was succesful. If the match is irrefutable (when it cannot fail to match),
@@ -232,7 +266,6 @@ See also https://github.com/rust-lang/rust/issues/14587
 }
 
 register_diagnostics! {
-    E0009,
     E0010,
     E0011,
     E0012,