diff --git a/contrib/isn/isn.c b/contrib/isn/isn.c
index 1880c91844e90..038c8ed4db7bd 100644
--- a/contrib/isn/isn.c
+++ b/contrib/isn/isn.c
@@ -726,7 +726,7 @@ string2ean(const char *str, struct Node *escontext, ean13 *result,
 			if (type != INVALID)
 				goto eaninvalid;
 			type = ISSN;
-			*aux1++ = pg_ascii_toupper((unsigned char) *aux2);
+			*aux1++ = toupper((unsigned char) *aux2);
 			length++;
 		}
 		else if (length == 9 && (digit || *aux2 == 'X' || *aux2 == 'x') && last)
@@ -736,7 +736,7 @@ string2ean(const char *str, struct Node *escontext, ean13 *result,
 				goto eaninvalid;
 			if (type == INVALID)
 				type = ISBN;	/* ISMN must start with 'M' */
-			*aux1++ = pg_ascii_toupper((unsigned char) *aux2);
+			*aux1++ = toupper((unsigned char) *aux2);
 			length++;
 		}
 		else if (length == 11 && digit && last)
diff --git a/contrib/spi/refint.c b/contrib/spi/refint.c
index 89898cad7b0d7..d5e25e07ae9e2 100644
--- a/contrib/spi/refint.c
+++ b/contrib/spi/refint.c
@@ -321,7 +321,7 @@ check_foreign_key(PG_FUNCTION_ARGS)
 	if (nrefs < 1)
 		/* internal error */
 		elog(ERROR, "check_foreign_key: %d (< 1) number of references specified", nrefs);
-	action = pg_ascii_tolower((unsigned char) *(args[1]));
+	action = tolower((unsigned char) *(args[1]));
 	if (action != 'r' && action != 'c' && action != 's')
 		/* internal error */
 		elog(ERROR, "check_foreign_key: invalid action %s", args[1]);
diff --git a/src/backend/access/nbtree/nbtutils.c b/src/backend/access/nbtree/nbtutils.c
index 86293cba5abf9..c71d1b6f2e1e0 100644
--- a/src/backend/access/nbtree/nbtutils.c
+++ b/src/backend/access/nbtree/nbtutils.c
@@ -63,7 +63,7 @@ static bool _bt_check_compare(IndexScanDesc scan, ScanDirection dir,
 							  bool *continuescan, int *ikey);
 static bool _bt_check_rowcompare(ScanKey skey,
 								 IndexTuple tuple, int tupnatts, TupleDesc tupdesc,
-								 ScanDirection dir, bool *continuescan);
+								 ScanDirection dir, bool forcenonrequired, bool *continuescan);
 static void _bt_checkkeys_look_ahead(IndexScanDesc scan, BTReadPageState *pstate,
 									 int tupnatts, TupleDesc tupdesc);
 static int	_bt_keep_natts(Relation rel, IndexTuple lastleft,
@@ -2902,10 +2902,8 @@ _bt_check_compare(IndexScanDesc scan, ScanDirection dir,
 		/* row-comparison keys need special processing */
 		if (key->sk_flags & SK_ROW_HEADER)
 		{
-			Assert(!forcenonrequired);	/* forbidden by _bt_set_startikey */
-
 			if (_bt_check_rowcompare(key, tuple, tupnatts, tupdesc, dir,
-									 continuescan))
+									 forcenonrequired, continuescan))
 				continue;
 			return false;
 		}
@@ -3062,7 +3060,8 @@ _bt_check_compare(IndexScanDesc scan, ScanDirection dir,
  */
 static bool
 _bt_check_rowcompare(ScanKey skey, IndexTuple tuple, int tupnatts,
-					 TupleDesc tupdesc, ScanDirection dir, bool *continuescan)
+					 TupleDesc tupdesc, ScanDirection dir,
+					 bool forcenonrequired, bool *continuescan)
 {
 	ScanKey		subkey = (ScanKey) DatumGetPointer(skey->sk_argument);
 	int32		cmpresult = 0;
@@ -3102,7 +3101,11 @@ _bt_check_rowcompare(ScanKey skey, IndexTuple tuple, int tupnatts,
 
 		if (isNull)
 		{
-			if (subkey->sk_flags & SK_BT_NULLS_FIRST)
+			if (forcenonrequired)
+			{
+				/* treating scan's keys as non-required */
+			}
+			else if (subkey->sk_flags & SK_BT_NULLS_FIRST)
 			{
 				/*
 				 * Since NULLs are sorted before non-NULLs, we know we have
@@ -3156,8 +3159,12 @@ _bt_check_rowcompare(ScanKey skey, IndexTuple tuple, int tupnatts,
 			 */
 			Assert(subkey != (ScanKey) DatumGetPointer(skey->sk_argument));
 			subkey--;
-			if ((subkey->sk_flags & SK_BT_REQFWD) &&
-				ScanDirectionIsForward(dir))
+			if (forcenonrequired)
+			{
+				/* treating scan's keys as non-required */
+			}
+			else if ((subkey->sk_flags & SK_BT_REQFWD) &&
+					 ScanDirectionIsForward(dir))
 				*continuescan = false;
 			else if ((subkey->sk_flags & SK_BT_REQBKWD) &&
 					 ScanDirectionIsBackward(dir))
@@ -3209,7 +3216,7 @@ _bt_check_rowcompare(ScanKey skey, IndexTuple tuple, int tupnatts,
 			break;
 	}
 
-	if (!result)
+	if (!result && !forcenonrequired)
 	{
 		/*
 		 * Tuple fails this qual.  If it's a required qual for the current
diff --git a/src/backend/commands/copyfromparse.c b/src/backend/commands/copyfromparse.c
index f52f2477df129..f5fc346e2013b 100644
--- a/src/backend/commands/copyfromparse.c
+++ b/src/backend/commands/copyfromparse.c
@@ -1538,7 +1538,7 @@ GetDecimalFromHex(char hex)
 	if (isdigit((unsigned char) hex))
 		return hex - '0';
 	else
-		return pg_ascii_tolower((unsigned char) hex) - 'a' + 10;
+		return tolower((unsigned char) hex) - 'a' + 10;
 }
 
 /*
diff --git a/src/backend/utils/adt/inet_net_pton.c b/src/backend/utils/adt/inet_net_pton.c
index 3b0db2a379937..ef2236d9f0430 100644
--- a/src/backend/utils/adt/inet_net_pton.c
+++ b/src/backend/utils/adt/inet_net_pton.c
@@ -115,7 +115,8 @@ inet_cidr_pton_ipv4(const char *src, u_char *dst, size_t size)
 		src++;					/* skip x or X. */
 		while ((ch = *src++) != '\0' && isxdigit((unsigned char) ch))
 		{
-			ch = pg_ascii_tolower((unsigned char) ch);
+			if (isupper((unsigned char) ch))
+				ch = tolower((unsigned char) ch);
 			n = strchr(xdigits, ch) - xdigits;
 			assert(n >= 0 && n <= 15);
 			if (dirty == 0)
diff --git a/src/bin/psql/tab-complete.in.c b/src/bin/psql/tab-complete.in.c
index 620830feb9d75..2c0b4f28c14dd 100644
--- a/src/bin/psql/tab-complete.in.c
+++ b/src/bin/psql/tab-complete.in.c
@@ -3289,7 +3289,7 @@ match_previous_words(int pattern_id,
 		COMPLETE_WITH("FORMAT", "FREEZE", "DELIMITER", "NULL",
 					  "HEADER", "QUOTE", "ESCAPE", "FORCE_QUOTE",
 					  "FORCE_NOT_NULL", "FORCE_NULL", "ENCODING", "DEFAULT",
-					  "ON_ERROR", "LOG_VERBOSITY");
+					  "ON_ERROR", "LOG_VERBOSITY", "REJECT_LIMIT");
 
 	/* Complete COPY <sth> FROM|TO filename WITH (FORMAT */
 	else if (Matches("COPY|\\copy", MatchAny, "FROM|TO", MatchAny, "WITH", "(", "FORMAT"))