diff --git a/src/testdir/test64.in b/src/testdir/test64.in
index 82669b0..e666ab9 100644
--- a/src/testdir/test64.in
+++ b/src/testdir/test64.in
@@ -340,6 +340,7 @@
 :call add(tl, [2, '^\%(.*bar\)\@!.*\zsfoo', ' foo bar '])
 :call add(tl, [2, '^\%(.*bar\)\@!.*\zsfoo', ' foo xxx ', 'foo'])
 :call add(tl, [2, '[ ]\@!\p\%([ ]\@!\p\)*:', 'implicit mappings:', 'mappings:'])
+:call add(tl, [2, '[ ]\@!\p\([ ]\@!\p\)*:', 'implicit mappings:', 'mappings:', 's'])
 :call add(tl, [2, 'm\k\+_\@=\%(_\@!\k\)\@<=\k\+e', 'mx__xe', 'mx__xe'])
 :call add(tl, [2, '\%(\U\@<=S\k*\|S\l\)R', 'SuR', 'SuR'])
 :"
diff --git a/src/testdir/test64.ok b/src/testdir/test64.ok
index d08227f..c778e9e 100644
--- a/src/testdir/test64.ok
+++ b/src/testdir/test64.ok
@@ -776,6 +776,9 @@
 OK 0 - [ ]\@!\p\%([ ]\@!\p\)*:
 OK 1 - [ ]\@!\p\%([ ]\@!\p\)*:
 OK 2 - [ ]\@!\p\%([ ]\@!\p\)*:
+OK 0 - [ ]\@!\p\([ ]\@!\p\)*:
+OK 1 - [ ]\@!\p\([ ]\@!\p\)*:
+OK 2 - [ ]\@!\p\([ ]\@!\p\)*:
 OK 0 - m\k\+_\@=\%(_\@!\k\)\@<=\k\+e
 OK 1 - m\k\+_\@=\%(_\@!\k\)\@<=\k\+e
 OK 2 - m\k\+_\@=\%(_\@!\k\)\@<=\k\+e