[DX] Fix message on callable filter returns union or intersection

Author: samsonasik

src/Assert/Filter.php

@@ -7,10 +7,14 @@
 use Closure;
 use InvalidArgumentException;
 use ReflectionFunction;
+use ReflectionIntersectionType;
 use ReflectionMethod;
 use ReflectionNamedType;
+use ReflectionUnionType;
 
+use function array_map;
 use function gettype;
+use function implode;
 use function is_object;
 use function sprintf;
 
@@ -30,6 +34,19 @@ public static function boolean(callable $filter): void
 
         $returnType = $reflection->getReturnType();
 
+        if ($returnType instanceof ReflectionUnionType || $returnType instanceof ReflectionIntersectionType) {
+            $separator = $returnType instanceof ReflectionUnionType ? '|' : '&';
+            throw new InvalidArgumentException(
+                sprintf(
+                    'Expected a bool return type on callable filter, %s given',
+                    implode($separator, array_map(
+                        static fn (ReflectionNamedType $type): string => $type->getName(),
+                        $returnType->getTypes()
+                    ))
+                )
+            );
+        }
+
         if (! $returnType instanceof ReflectionNamedType) {
             throw new InvalidArgumentException('Expected a bool return type on callable filter, null given');
         }

tests/FilterTest.php

@@ -68,4 +68,37 @@ public function __invoke(int $datum): string
 
         AtLeast::once($data, $filter);
     }
+
+    public function testWithUnionReturnTypeCallable(): void
+    {
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage('Expected a bool return type on callable filter, string|bool given');
+
+        $data   = [1, 2, 3];
+        $filter = new class {
+            public function __invoke(int $datum): string|bool
+            {
+                return 'test';
+            }
+        };
+
+        AtLeast::once($data, $filter);
+    }
+
+    public function testWithIntersectionTypeCallable(): void
+    {
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage(
+            'Expected a bool return type on callable filter, ArrayLookup\Tests\A&ArrayLookup\Tests\B given'
+        );
+
+        $data   = [1, 2, 3];
+        $filter = new class {
+            public function __invoke(int $datum): A&B
+            {
+            }
+        };
+
+        AtLeast::once($data, $filter);
+    }
 }