diff --git a/src/cmdexpand.c b/src/cmdexpand.c
index a4eae117cb..e354c4a356 100644
--- a/src/cmdexpand.c
+++ b/src/cmdexpand.c
@@ -4542,6 +4542,8 @@ f_getcompltype(typval_T *argvars, typval_T *rettv)
 	return;
 
     pat = tv_get_string(&argvars[0]);
+    if (check_for_string_arg(argvars, 0) == FAIL)
+	return;
 
     ExpandInit(&xpc);
 
diff --git a/src/testdir/test_cmdline.vim b/src/testdir/test_cmdline.vim
index 22efd45dd7..1ecf7ce19e 100644
--- a/src/testdir/test_cmdline.vim
+++ b/src/testdir/test_cmdline.vim
@@ -4591,6 +4591,7 @@ func Test_range_complete()
 endfunc
 
 func Test_getcompltype()
+  call assert_fails('call getcompltype({})', 'E731:')
   call assert_equal(getcompltype(''), 'command')
   call assert_equal(getcompltype('dummy '), '')
   call assert_equal(getcompltype('cd '), 'dir_in_path')