diff --git a/src/protocol/ast.rs b/src/protocol/ast.rs
index 2ec91950cccab65a5a367f7f582b1ee9bb61a25a..ccb79434b3832c10b0220d8d4286afba8a6d9af3 100644
--- a/src/protocol/ast.rs
+++ b/src/protocol/ast.rs
@@ -1279,6 +1279,7 @@ impl Expression {
 #[derive(Debug, Clone, Copy)]
 pub enum AssignmentOperator {
     Set,
+    Concatenated,
     Multiplied,
     Divided,
     Remained,