diff --git a/tests/modular/const_extension_type/def.dart b/tests/modular/const_extension_type/def.dart
new file mode 100644
index 00000000000..c6b260186f7
--- /dev/null
+++ b/tests/modular/const_extension_type/def.dart
@@ -0,0 +1,7 @@
+// Copyright (c) 2023, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+const val = ExtString('hello');
+
+extension type const ExtString(String s) {}
diff --git a/tests/modular/const_extension_type/main.dart b/tests/modular/const_extension_type/main.dart
new file mode 100644
index 00000000000..d5c7f7939ae
--- /dev/null
+++ b/tests/modular/const_extension_type/main.dart
@@ -0,0 +1,15 @@
+// Copyright (c) 2023, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'package:expect/expect.dart';
+
+import 'def.dart';
+
+main() {
+  ExtString x = val;
+  fn(x);
+}
+
+void fn(ExtString es) {
+  Expect.equals('hello', es.toString());
+}
diff --git a/tests/modular/const_extension_type/modules.yaml b/tests/modular/const_extension_type/modules.yaml
new file mode 100644
index 00000000000..e1daed834ae
--- /dev/null
+++ b/tests/modular/const_extension_type/modules.yaml
@@ -0,0 +1,10 @@
+# Copyright (c) 2023, the Dart project authors.  Please see the AUTHORS file
+# for details. All rights reserved. Use of this source code is governed by a
+# BSD-style license that can be found in the LICENSE file.
+#
+# A constant created with an extension type should be assignable to the same
+# extension type in a different module.
+dependencies:
+  main: [def, expect]
+flags:
+  - inline-class
\ No newline at end of file