Fix new exception renderer compatibility with closure middlewares (#5…

…1614)

In an application with a closure/inline middleware in a controller, the exception renderer fails with "Object of class Closure could not be converted to string"

src/Illuminate/Foundation/Exceptions/Renderer/Exception.php

@@ -2,6 +2,7 @@
 
 namespace Illuminate\Foundation\Exceptions\Renderer;
 
+use Closure;
 use Composer\Autoload\ClassLoader;
 use Illuminate\Foundation\Bootstrap\HandleExceptions;
 use Illuminate\Http\Request;
@@ -173,7 +174,9 @@ public function applicationRouteContext()
         return $route ? array_filter([
             'controller' => $route->getActionName(),
             'route name' => $route->getName() ?: null,
-            'middleware' => implode(', ', $route->gatherMiddleware()),
+            'middleware' => implode(', ', array_map(function ($middleware) {
+                return $middleware instanceof Closure ? 'Closure' : $middleware;
+            }, $route->gatherMiddleware())),
         ]) : [];
     }