diff --git a/src/HookCallbackRule.php b/src/HookCallbackRule.php
index 667b4ff..270894a 100644
--- a/src/HookCallbackRule.php
+++ b/src/HookCallbackRule.php
@@ -66,6 +66,10 @@ public function processNode(Node $node, Scope $scope): array
             return [];
         }
 
+        if (! $this->reflectionProvider->hasFunction($node->name, $scope)) {
+            return [];
+        }
+
         $functionReflection = $this->reflectionProvider->getFunction($node->name, $scope);
 
         if (! in_array($functionReflection->getName(), self::SUPPORTED_FUNCTIONS, true)) {