One more keyword
diff --git a/src/expr.rs b/src/expr.rs
index 10e429f..907a247 100644
--- a/src/expr.rs
+++ b/src/expr.rs
@@ -560,7 +560,7 @@
 
     named!(expr_while -> Expr, do_parse!(
         lt: option!(terminated!(lifetime, punct!(":"))) >>
-        punct!("while") >>
+        keyword!("while") >>
         cond: expr >>
         while_block: block >>
         (Expr::While(