Merge branch '5.1' into 5.2

* 5.1:
  Use ::class keyword when possible

Author: fabpot

ErrorHandler.php

@@ -187,7 +187,7 @@ public function __construct(BufferingLogger $bootstrappingLogger = null, bool $d
             $this->bootstrappingLogger = $bootstrappingLogger;
             $this->setDefaultLogger($bootstrappingLogger);
         }
-        $traceReflector = new \ReflectionProperty('Exception', 'trace');
+        $traceReflector = new \ReflectionProperty(\Exception::class, 'trace');
         $traceReflector->setAccessible(true);
         $this->configureException = \Closure::bind(static function ($e, $trace, $file = null, $line = null) use ($traceReflector) {
             $traceReflector->setValue($e, $trace);

Resources/views/exception_full.html.php

@@ -17,7 +17,7 @@
             );
         </script>
 
-        <?php if (class_exists('Symfony\Component\HttpKernel\Kernel')) { ?>
+        <?php if (class_exists(\Symfony\Component\HttpKernel\Kernel::class)) { ?>
             <header>
                 <div class="container">
                     <h1 class="logo"><?= $this->include('assets/images/symfony-logo.svg'); ?> Symfony Exception</h1>