diff --git a/crates/milli/src/error.rs b/crates/milli/src/error.rs
index 3a9c81e10..6c60dcecc 100644
--- a/crates/milli/src/error.rs
+++ b/crates/milli/src/error.rs
@@ -56,6 +56,8 @@ pub enum InternalError {
     #[error(transparent)]
     SerdeJson(#[from] serde_json::Error),
     #[error(transparent)]
+    BincodeError(#[from] bincode::Error),
+    #[error(transparent)]
     Serialization(#[from] SerializationError),
     #[error(transparent)]
     Store(#[from] MdbError),
diff --git a/crates/milli/src/update/new/merger.rs b/crates/milli/src/update/new/merger.rs
index 9d0d8e176..f6876b3d9 100644
--- a/crates/milli/src/update/new/merger.rs
+++ b/crates/milli/src/update/new/merger.rs
@@ -48,8 +48,7 @@ where
     }
 
     let mut file = tempfile::tempfile()?;
-    /// manage error
-    bincode::serialize_into(&mut file, &rtree).unwrap();
+    bincode::serialize_into(&mut file, &rtree).map_err(InternalError::BincodeError)?;
     file.sync_all()?;
 
     let rtree_mmap = unsafe { Mmap::map(&file)? };