From 3966f4efffb4a348cef0234e8394cf12f506679d Mon Sep 17 00:00:00 2001
From: han0110 <tinghan0110@gmail.com>
Date: Tue, 21 Jun 2022 15:02:17 +0800
Subject: [PATCH] fix: negate the subtrahend when processing `Expression::Sum`
 in `Evaluator::add_expression`

---
 halo2_proofs/src/plonk/evaluation.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/halo2_proofs/src/plonk/evaluation.rs b/halo2_proofs/src/plonk/evaluation.rs
index 954bafe136..b38c282c7a 100644
--- a/halo2_proofs/src/plonk/evaluation.rs
+++ b/halo2_proofs/src/plonk/evaluation.rs
@@ -404,7 +404,7 @@ impl<C: CurveAffine> Evaluator<C> {
                         let result_a = self.add_expression(a);
                         let result_b = self.add_expression(b_int);
                         if result_a == ValueSource::Constant(0) {
-                            result_b
+                            self.add_calculation(Calculation::Negate(result_b))
                         } else if result_b == ValueSource::Constant(0) {
                             result_a
                         } else {