diff --git a/src/testdir/test_substitute.vim b/src/testdir/test_substitute.vim
index 61c9cb3..a137aa5 100644
--- a/src/testdir/test_substitute.vim
+++ b/src/testdir/test_substitute.vim
@@ -881,6 +881,12 @@
   call assert_equal([], submatch(1, 1))
 endfunc
 
+func Test_submatch_list_concatenate()
+  let pat = 'A\(.\)'
+  let Rep = {-> string([submatch(0, 1)] + [[submatch(1)]])}
+  call substitute('A1', pat, Rep, '')->assert_equal("[['A1'], ['1']]")
+endfunc
+
 func Test_substitute_expr_arg()
   call assert_equal('123456789-123456789=', substitute('123456789',
 	\ '\(.\)\(.\)\(.\)\(.\)\(.\)\(.\)\(.\)\(.\)\(.\)',