diff --git a/src/backend/parser/analyze.c b/src/backend/parser/analyze.c
index 438b077004..15669c8238 100644
--- a/src/backend/parser/analyze.c
+++ b/src/backend/parser/analyze.c
@@ -3170,13 +3170,22 @@ transformLockingClause(ParseState *pstate, Query *qry, LockingClause *lc,
 
 	if (lockedRels == NIL)
 	{
-		/* all regular tables used in query */
+		/*
+		 * Lock all regular tables used in query and its subqueries.  We
+		 * examine inFromCl to exclude auto-added RTEs, particularly NEW/OLD
+		 * in rules.  This is a bit of an abuse of a mostly-obsolete flag, but
+		 * it's convenient.  We can't rely on the namespace mechanism that has
+		 * largely replaced inFromCl, since for example we need to lock
+		 * base-relation RTEs even if they are masked by upper joins.
+		 */
 		i = 0;
 		foreach(rt, qry->rtable)
 		{
 			RangeTblEntry *rte = (RangeTblEntry *) lfirst(rt);
 
 			++i;
+			if (!rte->inFromCl)
+				continue;
 			switch (rte->rtekind)
 			{
 				case RTE_RELATION:
@@ -3206,7 +3215,11 @@ transformLockingClause(ParseState *pstate, Query *qry, LockingClause *lc,
 	}
 	else
 	{
-		/* just the named tables */
+		/*
+		 * Lock just the named tables.  As above, we allow locking any base
+		 * relation regardless of alias-visibility rules, so we need to
+		 * examine inFromCl to exclude OLD/NEW.
+		 */
 		foreach(l, lockedRels)
 		{
 			RangeVar   *thisrel = (RangeVar *) lfirst(l);
@@ -3227,6 +3240,8 @@ transformLockingClause(ParseState *pstate, Query *qry, LockingClause *lc,
 				RangeTblEntry *rte = (RangeTblEntry *) lfirst(rt);
 
 				++i;
+				if (!rte->inFromCl)
+					continue;
 				if (strcmp(rte->eref->aliasname, thisrel->relname) == 0)
 				{
 					switch (rte->rtekind)
diff --git a/src/include/nodes/parsenodes.h b/src/include/nodes/parsenodes.h
index e28248af32..7af13dee43 100644
--- a/src/include/nodes/parsenodes.h
+++ b/src/include/nodes/parsenodes.h
@@ -929,10 +929,10 @@ typedef struct PartitionCmd
  *	  inFromCl marks those range variables that are listed in the FROM clause.
  *	  It's false for RTEs that are added to a query behind the scenes, such
  *	  as the NEW and OLD variables for a rule, or the subqueries of a UNION.
- *	  This flag is not used anymore during parsing, since the parser now uses
- *	  a separate "namespace" data structure to control visibility, but it is
- *	  needed by ruleutils.c to determine whether RTEs should be shown in
- *	  decompiled queries.
+ *	  This flag is not used during parsing (except in transformLockingClause,
+ *	  q.v.); the parser now uses a separate "namespace" data structure to
+ *	  control visibility.  But it is needed by ruleutils.c to determine
+ *	  whether RTEs should be shown in decompiled queries.
  *
  *	  requiredPerms and checkAsUser specify run-time access permissions
  *	  checks to be performed at query startup.  The user must have *all*