From 300522ad2f07fd4cbfbd8952d0e46edc6a928f9e Mon Sep 17 00:00:00 2001
From: Abdul Malik Ikhsan <samsonasik@gmail.com>
Date: Fri, 27 Feb 2026 00:47:34 +0700
Subject: [PATCH] Fix Filter Assert on callable without return type

---
 src/Assert/Filter.php | 9 +++++----
 tests/FilterTest.php  | 2 +-
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/src/Assert/Filter.php b/src/Assert/Filter.php
index 2e6a79b..533f192 100644
--- a/src/Assert/Filter.php
+++ b/src/Assert/Filter.php
@@ -10,6 +10,7 @@
 use ReflectionIntersectionType;
 use ReflectionMethod;
 use ReflectionNamedType;
+use ReflectionType;
 use ReflectionUnionType;
 use Webmozart\Assert\Assert;
 
@@ -37,6 +38,9 @@ public static function boolean(callable $filter): void
         };
 
         $returnType = $reflection->getReturnType();
+        if (! $returnType instanceof ReflectionType) {
+            throw new InvalidArgumentException(sprintf(self::MESSAGE, 'none'));
+        }
 
         if ($returnType instanceof ReflectionUnionType || $returnType instanceof ReflectionIntersectionType) {
             $separator = $returnType instanceof ReflectionUnionType ? '|' : '&';
@@ -68,12 +72,9 @@ function (ReflectionNamedType|ReflectionIntersectionType $reflectionType): strin
             );
         }
 
-        if (! $returnType instanceof ReflectionNamedType) {
-            throw new InvalidArgumentException(sprintf(self::MESSAGE, 'mixed'));
-        }
+        Assert::isInstanceOf($returnType, ReflectionNamedType::class);
 
         $returnTypeName = $returnType->getName();
-
         if ($returnType->allowsNull()) {
             throw new InvalidArgumentException(sprintf(
                 self::MESSAGE,
diff --git a/tests/FilterTest.php b/tests/FilterTest.php
index b9ecad0..ab3a9f6 100644
--- a/tests/FilterTest.php
+++ b/tests/FilterTest.php
@@ -37,7 +37,7 @@ public function testOnceWithStringFilter(): void
     public function testWithoutReturnTypeCallable(): void
     {
         $this->expectException(InvalidArgumentException::class);
-        $this->expectExceptionMessage('Expected a bool return type on callable filter, mixed given');
+        $this->expectExceptionMessage('Expected a bool return type on callable filter, none given');
 
         $data = [1, 2, 3];