diff --git a/src/testdir/test_vim9_expr.vim b/src/testdir/test_vim9_expr.vim
index a4e3e9e..cf4347c 100644
--- a/src/testdir/test_vim9_expr.vim
+++ b/src/testdir/test_vim9_expr.vim
@@ -1500,6 +1500,12 @@
       assert_equal([[1, 2]], lln)
   END
   v9.CheckDefAndScriptSuccess(lines)
+
+  lines =<< trim END
+      var ln: list<number> = [0]
+      var lln: list<list<number>> = [ln + []]
+  END
+  v9.CheckDefAndScriptSuccess(lines)
 enddef
 
 " test multiply, divide, modulo