From e14a2474fbcf0e97fc6b0b7e30de8a6924e0ab2a Mon Sep 17 00:00:00 2001
From: Vincent Langlet <vincentlanglet@hotmail.fr>
Date: Fri, 2 May 2025 17:41:32 +0200
Subject: [PATCH] Fix warning

---
 src/ExtensionSet.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/ExtensionSet.php b/src/ExtensionSet.php
index 04392b2e6..85a98cf3c 100644
--- a/src/ExtensionSet.php
+++ b/src/ExtensionSet.php
@@ -507,7 +507,7 @@ final class ExtensionSet
                 default => throw new \InvalidArgumentException(\sprintf('Invalid associativity "%s" for operator "%s".', $op['associativity'], $operator)),
             };
 
-            if ($op['callable']) {
+            if (isset($op['callable'])) {
                 $expressionParsers[] = $this->convertInfixExpressionParser($op['class'], $operator, $op['precedence'], $op['associativity'], $op['precedence_change'] ?? null, $op['aliases'] ?? [], $op['callable']);
             } else {
                 $expressionParsers[] = new BinaryOperatorExpressionParser($op['class'], $operator, $op['precedence'], $op['associativity'], $op['precedence_change'] ?? null, '', $op['aliases'] ?? []);