From cee96fab39299449f877c3db997d1cf421abc8af Mon Sep 17 00:00:00 2001
From: Florian Hartwig <florian.j.hartwig@gmail.com>
Date: Wed, 27 Jan 2016 21:10:35 +0100
Subject: [PATCH] Point out that char is 32 bit value

---
 src/types.rs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/types.rs b/src/types.rs
index 42824c36ec66..d41896cd490a 100644
--- a/src/types.rs
+++ b/src/types.rs
@@ -544,7 +544,9 @@ impl LateLintPass for CharLitAsU8 {
             if let ExprLit(ref l) = e.node {
                 if let Lit_::LitChar(_) = l.node {
                     if ty::TyUint(UintTy::TyU8) == cx.tcx.expr_ty(expr).sty && !in_macro(cx, expr.span) {
-                        let msg = "casting character literal to u8.";
+                        let msg = "casting character literal to u8. `char`s \
+                                   are 4 bytes wide in rust, so casting to u8 \
+                                   truncates them";
                         let help = format!("Consider using a byte literal \
                                             instead:\nb{}",
                                           snippet(cx, e.span, "'x'"));