Fix optimizing non-public named closures

src/Node/Expression/CallExpression.php

@@ -289,6 +289,7 @@ abstract class CallExpression extends AbstractExpression
             return $this->reflector = [$r, $callable, $r->class.'::'.$r->name];
         }
 
+        $checkVisibility = $callable instanceof \Closure;
         $r = new \ReflectionFunction(\Closure::fromCallable($callable));
 
         if (false !== strpos($r->name, '{closure}')) {
@@ -305,6 +306,10 @@ abstract class CallExpression extends AbstractExpression
             $callable = $callableName = $r->name;
         }
 
+        if ($checkVisibility && \is_array($callable) && method_exists(...$callable) && !(new \ReflectionMethod(...$callable))->isPublic()) {
+            $callable = $r->getClosure();
+        }
+
         return $this->reflector = [$r, $callable, $callableName];
     }
 }

tests/Node/Expression/FilterTest.php

@@ -48,12 +48,17 @@ class FilterTest extends NodeTestCase
             {
                 return [
                     new TwigFilter('foo', \Closure::fromCallable([$this, 'foo'])),
+                    new TwigFilter('foobar', \Closure::fromCallable([$this, 'foobar'])),
                 ];
             }
 
             public function foo()
             {
             }
+
+            protected function foobar()
+            {
+            }
         };
         $environment->addExtension($extension);
 
@@ -127,6 +132,9 @@ class FilterTest extends NodeTestCase
         $node = $this->createFilter($string, 'foo');
         $tests[] = [$node, sprintf('$this->extensions[\'%s\']->foo("abc")', \get_class($extension)), $environment];
 
+        $node = $this->createFilter($string, 'foobar');
+        $tests[] = [$node, '$this->env->getFilter(\'foobar\')->getCallable()("abc")', $environment];
+
         return $tests;
     }