diff --git a/src/protocol/tests/utils.rs b/src/protocol/tests/utils.rs
index 4fcdf8f1ccf5bed0b8548b4590d393395a6194af..6bed679520f0ac6a2d6f63cedaa64e30e99164b2 100644
--- a/src/protocol/tests/utils.rs
+++ b/src/protocol/tests/utils.rs
@@ -1197,6 +1197,9 @@ fn seek_expr_in_expr<F: Fn(&Expression) -> bool>(heap: &Heap, start: ExpressionI
             }
             None
         },
+        Expression::Cast(expr) => {
+            seek_expr_in_expr(heap, expr.subject, f)
+        }
         Expression::Call(expr) => {
             for arg in &expr.arguments {
                 if let Some(id) = seek_expr_in_expr(heap, *arg, f) {