diff --git a/src/testdir/test_syntax.vim b/src/testdir/test_syntax.vim
index cd06892..8a02185 100644
--- a/src/testdir/test_syntax.vim
+++ b/src/testdir/test_syntax.vim
@@ -428,7 +428,11 @@
   call setline(1, '#define FOO')
   syntax on
   set filetype=c
+
   ownsyntax perl
+  " this should not crash
+  set
+
   call assert_equal('perlComment', synIDattr(synID(line('.'), col('.'), 1), 'name'))
   call assert_equal('c',    b:current_syntax)
   call assert_equal('perl', w:current_syntax)