diff --git a/src/protocol/arena.rs b/src/protocol/arena.rs
index 1e4b64f9ae2b6d7e47f4e24d33b1a6a1b3b7d905..ad5356c82fc4dcb769f1205b58a61bb81ef69c16 100644
--- a/src/protocol/arena.rs
+++ b/src/protocol/arena.rs
@@ -8,7 +8,7 @@ pub struct Id<T> {
     _phantom: PhantomData<T>,
 }
 #[derive(Debug, serde::Serialize, serde::Deserialize)]
-pub struct Arena<T> {
+pub(crate) struct Arena<T> {
     store: Vec<T>,
 }
 //////////////////////////////////