[PATCH]Feature improvement for MERGE tab completion

[bt22kawamotok]

Hi!

I created a patch for improving MARGE tab completion.
Currently there is a problem with "MERGE INTO dst as d Using src as s ON 
d.key = s.key WHEN <tab>" is typed, "MATCHED" and "NOT MATCHED" is not 
completed.
There is also a problem that typing "MERGE INTO a AS <tab>" completes 
"USING".
This patch solves the above problems.
Regards,
Kotaro Kawamotodiff --git a/src/bin/psql/tab-complete.c b/src/bin/psql/tab-complete.c
index 62a39779b9..ed1f8c5f17 100644
--- a/src/bin/psql/tab-complete.c
+++ b/src/bin/psql/tab-complete.c
@@ -4068,7 +4068,7 @@ psql_completion(const char *text, int start, int end)
 	/* with [AS] alias */
 	else if (TailMatches("MERGE", "INTO", MatchAny, "AS", MatchAny))
 		COMPLETE_WITH("USING");
-	else if (TailMatches("MERGE", "INTO", MatchAny, MatchAny))
+	else if (TailMatches("MERGE", "INTO", MatchAny, MatchAny) && !TailMatches("AS"))
 		COMPLETE_WITH("USING");
 	else if (TailMatches("MERGE", "INTO", MatchAny, "AS", MatchAny, "USING"))
 		COMPLETE_WITH_SCHEMA_QUERY(Query_for_list_of_tables);
@@ -4095,6 +4095,12 @@ psql_completion(const char *text, int start, int end)
 		COMPLETE_WITH("WHEN MATCHED", "WHEN NOT MATCHED");
 	else if (TailMatches("USING", MatchAny, MatchAny, "ON", MatchAny))
 		COMPLETE_WITH("WHEN MATCHED", "WHEN NOT MATCHED");
+	else if (TailMatches("USING", MatchAny, "ON", MatchAny, "WHEN"))
+		COMPLETE_WITH("MATCHED", "NOT MATCHED");
+	else if (TailMatches("USING", MatchAny, "AS", MatchAny, "ON", MatchAny, "WHEN"))
+		COMPLETE_WITH("MATCHED", "NOT MATCHED");
+	else if (TailMatches("USING", MatchAny, MatchAny, "ON", MatchAny, "WHEN"))
+		COMPLETE_WITH("MATCHED", "NOT MATCHED");
 	else if (TailMatches("WHEN", "MATCHED"))
 		COMPLETE_WITH("THEN", "AND");
 	else if (TailMatches("WHEN", "NOT", "MATCHED"))