Fill in remaining synom descriptions
diff --git a/src/data.rs b/src/data.rs
index f9152f2..cfea802 100644
--- a/src/data.rs
+++ b/src/data.rs
@@ -137,6 +137,10 @@
                 named: fields,
             }
         ));
+
+        fn description() -> Option<&'static str> {
+            Some("named fields in a struct or struct variant")
+        }
     }
 
     impl Synom for FieldsUnnamed {
@@ -147,6 +151,10 @@
                 unnamed: fields,
             }
         ));
+
+        fn description() -> Option<&'static str> {
+            Some("unnamed fields in a tuple struct or tuple variant")
+        }
     }
 
     impl Field {