diff --git a/src/macros.rs b/src/macros.rs
index 8344c00..049a9fe 100644
--- a/src/macros.rs
+++ b/src/macros.rs
@@ -111,7 +111,7 @@ macro_rules! query_def_internal {
                 )+
             }
 
-            #[derive(Debug, Clone, Default)]
+            #[derive(Debug, Clone, Copy, Default)]
             $(#[$def_meta])
             *
             $vis struct $def {