1 files changed, 13 insertions, 0 deletions
diff --git a/src/nvim/eval/typval.c b/src/nvim/eval/typval.c
index e09fda173b..7e4066adb7 100644
--- a/src/nvim/eval/typval.c
+++ b/src/nvim/eval/typval.c
@@ -46,6 +46,8 @@ static char e_non_empty_string_required_for_argument_nr[]
   = N_("E1175: Non-empty string required for argument %d");
 static char e_number_required_for_argument_nr[]
   = N_("E1210: Number required for argument %d");
+static char e_string_or_list_required_for_argument_nr[]
+  = N_("E1222: String or List required for argument %d");
 
 bool tv_in_free_unref_items = false;
 
@@ -3880,6 +3882,17 @@ int tv_check_for_opt_number_arg(const typval_T *const args, const int idx)
           || tv_check_for_number_arg(args, idx) != FAIL) ? OK : FAIL;
 }
 
+/// Give an error and return FAIL unless "args[idx]" is a string or a list.
+int tv_check_for_string_or_list_arg(const typval_T *const args, const int idx)
+  FUNC_ATTR_NONNULL_ALL FUNC_ATTR_WARN_UNUSED_RESULT FUNC_ATTR_PURE
+{
+  if (args[idx].v_type != VAR_STRING && args[idx].v_type != VAR_LIST) {
+    semsg(_(e_string_or_list_required_for_argument_nr), idx + 1);
+    return FAIL;
+  }
+  return OK;
+}
+
 /// Get the string value of a "stringish" VimL object.
 ///
 /// @param[in]  tv  Object to get value of.