Merge branch '2.8' into 3.2

* 2.8:
  Using FQ name for PHP_VERSION_ID
  [Form] Fix \IntlDateFormatter timezone parameter usage to bypass PHP bug #66323
  Harden the debugging of Twig filters and functions
  bumped Symfony version to 2.8.22
  updated VERSION for 2.8.21
  updated CHANGELOG for 2.8.21
  bumped Symfony version to 2.7.29
  updated VERSION for 2.7.28
  update CONTRIBUTORS for 2.7.28
  updated CHANGELOG for 2.7.28

ClassCollectionLoader.php

@@ -256,7 +256,7 @@ REGEX;
 
         $output .= self::compressCode($rawChunk);
 
-        if (PHP_VERSION_ID >= 70000) {
+        if (\PHP_VERSION_ID >= 70000) {
             // PHP 7 memory manager will not release after token_get_all(), see https://bugs.php.net/70098
             unset($tokens, $rawChunk);
             gc_mem_caches();

ClassMapGenerator.php

@@ -64,7 +64,7 @@ class ClassMapGenerator
 
             $classes = self::findClasses($path);
 
-            if (PHP_VERSION_ID >= 70000) {
+            if (\PHP_VERSION_ID >= 70000) {
                 // PHP 7 memory manager will not release after token_get_all(), see https://bugs.php.net/70098
                 gc_mem_caches();
             }

Tests/ApcClassLoaderTest.php

@@ -11,10 +11,11 @@
 
 namespace Symfony\Component\ClassLoader\Tests;
 
+use PHPUnit\Framework\TestCase;
 use Symfony\Component\ClassLoader\ApcClassLoader;
 use Symfony\Component\ClassLoader\ClassLoader;
 
-class ApcClassLoaderTest extends \PHPUnit_Framework_TestCase
+class ApcClassLoaderTest extends TestCase
 {
     protected function setUp()
     {

Tests/ClassCollectionLoaderTest.php

@@ -11,6 +11,7 @@
 
 namespace Symfony\Component\ClassLoader\Tests;
 
+use PHPUnit\Framework\TestCase;
 use Symfony\Component\ClassLoader\ClassCollectionLoader;
 use Symfony\Component\ClassLoader\Tests\Fixtures\DeclaredClass;
 use Symfony\Component\ClassLoader\Tests\Fixtures\WarmedClass;
@@ -20,7 +21,7 @@ require_once __DIR__.'/Fixtures/ClassesWithParents/CInterface.php';
 require_once __DIR__.'/Fixtures/ClassesWithParents/B.php';
 require_once __DIR__.'/Fixtures/ClassesWithParents/A.php';
 
-class ClassCollectionLoaderTest extends \PHPUnit_Framework_TestCase
+class ClassCollectionLoaderTest extends TestCase
 {
     public function testTraitDependencies()
     {

Tests/ClassLoaderTest.php

@@ -11,9 +11,10 @@
 
 namespace Symfony\Component\ClassLoader\Tests;
 
+use PHPUnit\Framework\TestCase;
 use Symfony\Component\ClassLoader\ClassLoader;
 
-class ClassLoaderTest extends \PHPUnit_Framework_TestCase
+class ClassLoaderTest extends TestCase
 {
     public function testGetPrefixes()
     {

Tests/ClassMapGeneratorTest.php

@@ -11,9 +11,10 @@
 
 namespace Symfony\Component\ClassLoader\Tests;
 
+use PHPUnit\Framework\TestCase;
 use Symfony\Component\ClassLoader\ClassMapGenerator;
 
-class ClassMapGeneratorTest extends \PHPUnit_Framework_TestCase
+class ClassMapGeneratorTest extends TestCase
 {
     /**
      * @var string|null

Tests/Psr4ClassLoaderTest.php

@@ -11,9 +11,10 @@
 
 namespace Symfony\Component\ClassLoader\Tests;
 
+use PHPUnit\Framework\TestCase;
 use Symfony\Component\ClassLoader\Psr4ClassLoader;
 
-class Psr4ClassLoaderTest extends \PHPUnit_Framework_TestCase
+class Psr4ClassLoaderTest extends TestCase
 {
     /**
      * @param string $className

phpunit.xml.dist

@@ -5,6 +5,8 @@
          backupGlobals="false"
          colors="true"
          bootstrap="vendor/autoload.php"
+         failOnRisky="true"
+         failOnWarning="true"
 >
     <php>
         <ini name="error_reporting" value="-1" />