diff --git a/e2etests/regression_test.go b/e2etests/regression_test.go
index 6b35a551e..33eecefcb 100644
--- a/e2etests/regression_test.go
+++ b/e2etests/regression_test.go
@@ -29,6 +29,14 @@ B: goodbye {
 }
 
 A->B`,
+		},
+		{
+			name: "undeclared_nested_sequence",
+			script: `shape: sequence_diagram
+group.nested: {
+  a -> b
+}
+`,
 		},
 		{
 			name: "nested_steps",