diff --git a/bson.go b/bson.go
index 8740b15..a8a3604 100644
--- a/bson.go
+++ b/bson.go
@@ -142,7 +142,7 @@ func (id ObjectId) MarshalBSONValue() (bsontype.Type, []byte, error) {
 // BSON value representation of themselves. The BSON bytes and type can be
 // assumed to be valid. UnmarshalBSONValue must copy the BSON value bytes if it
 // wishes to retain the data after returning.
-func (id *ObjectId) UnmarshalBSONValue(tpe bsontype.Type, data []byte) error {
+func (id *ObjectId) UnmarshalBSONValue(_ bsontype.Type, data []byte) error {
 	var oid bsonprim.ObjectID
 	copy(oid[:], data)
 	*id = ObjectId(oid)