From 0ffbe900ce599d204536b9623291e05e965da23e Mon Sep 17 00:00:00 2001
From: Peter Eisentraut <peter@eisentraut.org>
Date: Thu, 9 Sep 2021 10:23:29 +0200
Subject: [PATCH] Fix _equalA_Const

639a86e36aaecb84faaf941dcd0b183ba0aba9e9 neglected to make the
necessary adjustments to _equalA_Const.  Found only via
COPY_PARSE_PLAN_TREES.
---
 src/backend/nodes/equalfuncs.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/src/backend/nodes/equalfuncs.c b/src/backend/nodes/equalfuncs.c
index 231380ccf74..4bad709f835 100644
--- a/src/backend/nodes/equalfuncs.c
+++ b/src/backend/nodes/equalfuncs.c
@@ -2409,8 +2409,14 @@ _equalParamRef(const ParamRef *a, const ParamRef *b)
 static bool
 _equalA_Const(const A_Const *a, const A_Const *b)
 {
-	if (!equal(&a->val, &b->val))	/* hack for in-line val field */
+	/*
+	 * Hack for in-line val field.  Also val is not valid is isnull is
+	 * true.
+	 */
+	if (!a->isnull && !b->isnull &&
+		!equal(&a->val, &b->val))
 		return false;
+	COMPARE_SCALAR_FIELD(isnull);
 	COMPARE_LOCATION_FIELD(location);
 
 	return true;