patch 8.1.0716: get warning message when 'completefunc' returns nothing
Problem: Get warning message when 'completefunc' returns nothing.
Solution: Allow for returning v:none to suppress the warning message.
(Yasuhiro Matsumoto, closes #3789)
diff --git a/runtime/doc/insert.txt b/runtime/doc/insert.txt
index a200fc5..e01eac9 100644
--- a/runtime/doc/insert.txt
+++ b/runtime/doc/insert.txt
@@ -1076,6 +1076,10 @@
The only value currently recognized is "always", the
effect is that the function is called whenever the
leading text is changed.
+
+If you want to suppress the warning message for an empty result, return
+v:none. This is useful to implement asynchronous completion with complete().
+
Other items are ignored.
For acting upon end of completion, see the |CompleteDone| autocommand event.