Simplify keyword parsing
diff --git a/src/data.rs b/src/data.rs
index 2f1cca7..fdcc4e9 100644
--- a/src/data.rs
+++ b/src/data.rs
@@ -132,10 +132,7 @@
     ));
 
     named!(pub visibility -> Visibility, alt!(
-        do_parse!(
-            keyword!("pub") >>
-            (Visibility::Public)
-        )
+        keyword!("pub") => { |_| Visibility::Public }
         |
         epsilon!() => { |_| Visibility::Inherited }
     ));