diff --git a/lib/edlang_driver/tests/programs/struct.ed b/lib/edlang_driver/tests/programs/struct.ed
index 5c0b7e78d..a6ad44048 100644
--- a/lib/edlang_driver/tests/programs/struct.ed
+++ b/lib/edlang_driver/tests/programs/struct.ed
@@ -5,7 +5,7 @@ struct Hello {
 }
 
 pub fn main() -> i64 {
-    let x: Hello = Hello {
+    let mut x: Hello = Hello {
         a: 2,
         b: 3,
     };