Set amount to the subtotal when the discount amount exceeds the subtotal

src/PricingManager/Action/CartDiscount.php

@@ -43,7 +43,7 @@ public function executeOnCart(EnvironmentInterface $environment): ActionInterfac
             $amount = Decimal::fromDecimal($amount->withScale(2));
         }
 
-        $amount = $amount->mul(-1);
+        $amount = $amount->toAdditiveInverse();
 
         //make sure that one rule is applied only once
         foreach ($priceCalculator->getModificators() as &$modificator) {