diff --git a/.php_cs.dist b/.php_cs.dist
index b28505eb45..35ef4ae8cb 100644
--- a/.php_cs.dist
+++ b/.php_cs.dist
@@ -9,7 +9,7 @@ return PhpCsFixer\Config::create()
         '@Symfony' => true,
         '@Symfony:risky' => true,
         '@PHPUnit75Migration:risky' => true,
-        'php_unit_dedicate_assert' => ['target' => '3.5'],
+        'php_unit_dedicate_assert' => ['target' => '5.6'],
         'phpdoc_no_empty_return' => false, // triggers almost always false positive
         'array_syntax' => ['syntax' => 'short'],
         'fopen_flags' => false,
diff --git a/.travis.yml b/.travis.yml
index ab6c2d09b8..e9830dfea5 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -196,6 +196,7 @@ install:
           git checkout -q FETCH_HEAD -- src/Symfony/Bridge/PhpUnit
           SYMFONY_VERSION=$(cat src/Symfony/Bridge/PhpUnit/composer.json | grep '^ *"dev-master". *"[1-9]' | grep -o '[0-9.]*')
           sed -i 's/"symfony\/phpunit-bridge": ".*"/"symfony\/phpunit-bridge": "'$SYMFONY_VERSION'.x@dev"/' composer.json
+          rm -rf .phpunit
       fi
 
     - |
diff --git a/src/Symfony/Bridge/Doctrine/Security/User/EntityUserProvider.php b/src/Symfony/Bridge/Doctrine/Security/User/EntityUserProvider.php
index b00cc52dcb..4c9603bd5e 100644
--- a/src/Symfony/Bridge/Doctrine/Security/User/EntityUserProvider.php
+++ b/src/Symfony/Bridge/Doctrine/Security/User/EntityUserProvider.php
@@ -14,6 +14,7 @@ namespace Symfony\Bridge\Doctrine\Security\User;
 use Doctrine\Common\Persistence\ManagerRegistry;
 use Symfony\Component\Security\Core\Exception\UnsupportedUserException;
 use Symfony\Component\Security\Core\Exception\UsernameNotFoundException;
+use Symfony\Component\Security\Core\User\PasswordUpgraderInterface;
 use Symfony\Component\Security\Core\User\UserInterface;
 use Symfony\Component\Security\Core\User\UserProviderInterface;
 
@@ -25,7 +26,7 @@ use Symfony\Component\Security\Core\User\UserProviderInterface;
  * @author Fabien Potencier <fabien@symfony.com>
  * @author Johannes M. Schmitt <schmittjoh@gmail.com>
  */
-class EntityUserProvider implements UserProviderInterface
+class EntityUserProvider implements UserProviderInterface, PasswordUpgraderInterface
 {
     private $registry;
     private $managerName;
@@ -107,6 +108,22 @@ class EntityUserProvider implements UserProviderInterface
         return $class === $this->getClass() || is_subclass_of($class, $this->getClass());
     }
 
+    /**
+     * {@inheritdoc}
+     */
+    public function upgradePassword(UserInterface $user, string $newEncodedPassword): void
+    {
+        $class = $this->getClass();
+        if (!$user instanceof $class) {
+            throw new UnsupportedUserException(sprintf('Instances of "%s" are not supported.', \get_class($user)));
+        }
+
+        $repository = $this->getRepository();
+        if ($repository instanceof PasswordUpgraderInterface) {
+            $repository->upgradePassword($user, $newEncodedPassword);
+        }
+    }
+
     private function getObjectManager()
     {
         return $this->registry->getManager($this->managerName);
diff --git a/src/Symfony/Bridge/Doctrine/Tests/Security/User/EntityUserProviderTest.php b/src/Symfony/Bridge/Doctrine/Tests/Security/User/EntityUserProviderTest.php
index 9ccfde55eb..cf79840fee 100644
--- a/src/Symfony/Bridge/Doctrine/Tests/Security/User/EntityUserProviderTest.php
+++ b/src/Symfony/Bridge/Doctrine/Tests/Security/User/EntityUserProviderTest.php
@@ -17,6 +17,7 @@ use PHPUnit\Framework\TestCase;
 use Symfony\Bridge\Doctrine\Security\User\EntityUserProvider;
 use Symfony\Bridge\Doctrine\Test\DoctrineTestHelper;
 use Symfony\Bridge\Doctrine\Tests\Fixtures\User;
+use Symfony\Component\Security\Core\User\PasswordUpgraderInterface;
 
 class EntityUserProviderTest extends TestCase
 {
@@ -176,6 +177,23 @@ class EntityUserProviderTest extends TestCase
         $provider->loadUserByUsername('name');
     }
 
+    public function testPasswordUpgrades()
+    {
+        $user = new User(1, 1, 'user1');
+
+        $repository = $this->getMockBuilder(PasswordUpgraderInterface::class)->getMock();
+        $repository->expects($this->once())
+            ->method('upgradePassword')
+            ->with($user, 'foobar');
+
+        $provider = new EntityUserProvider(
+            $this->getManager($this->getObjectManager($repository)),
+            'Symfony\Bridge\Doctrine\Tests\Fixtures\User'
+        );
+
+        $provider->upgradePassword($user, 'foobar');
+    }
+
     private function getManager($em, $name = null)
     {
         $manager = $this->getMockBuilder('Doctrine\Common\Persistence\ManagerRegistry')->getMock();
diff --git a/src/Symfony/Bridge/PhpUnit/CHANGELOG.md b/src/Symfony/Bridge/PhpUnit/CHANGELOG.md
index 9c106e3c9f..17c3f201bf 100644
--- a/src/Symfony/Bridge/PhpUnit/CHANGELOG.md
+++ b/src/Symfony/Bridge/PhpUnit/CHANGELOG.md
@@ -11,6 +11,7 @@ CHANGELOG
 
  * made the bridge act as a polyfill for newest PHPUnit features
  * added `SetUpTearDownTrait` to allow working around the `void` return-type added by PHPUnit 8
+ * added namespace aliases for PHPUnit < 6
 
 4.3.0
 -----
diff --git a/src/Symfony/Bridge/PhpUnit/CoverageListener.php b/src/Symfony/Bridge/PhpUnit/CoverageListener.php
index d41c26968f..805f9222a5 100644
--- a/src/Symfony/Bridge/PhpUnit/CoverageListener.php
+++ b/src/Symfony/Bridge/PhpUnit/CoverageListener.php
@@ -11,7 +11,7 @@
 
 namespace Symfony\Bridge\PhpUnit;
 
-if (class_exists('PHPUnit_Runner_Version') && version_compare(\PHPUnit_Runner_Version::id(), '6.0.0', '<')) {
+if (version_compare(\PHPUnit\Runner\Version::id(), '6.0.0', '<')) {
     class_alias('Symfony\Bridge\PhpUnit\Legacy\CoverageListenerForV5', 'Symfony\Bridge\PhpUnit\CoverageListener');
 } elseif (version_compare(\PHPUnit\Runner\Version::id(), '7.0.0', '<')) {
     class_alias('Symfony\Bridge\PhpUnit\Legacy\CoverageListenerForV6', 'Symfony\Bridge\PhpUnit\CoverageListener');
diff --git a/src/Symfony/Bridge/PhpUnit/DeprecationErrorHandler.php b/src/Symfony/Bridge/PhpUnit/DeprecationErrorHandler.php
index b301201cbc..36c5fdf20a 100644
--- a/src/Symfony/Bridge/PhpUnit/DeprecationErrorHandler.php
+++ b/src/Symfony/Bridge/PhpUnit/DeprecationErrorHandler.php
@@ -11,6 +11,8 @@
 
 namespace Symfony\Bridge\PhpUnit;
 
+use PHPUnit\Framework\TestResult;
+use PHPUnit\Util\ErrorHandler;
 use Symfony\Bridge\PhpUnit\DeprecationErrorHandler\Configuration;
 use Symfony\Bridge\PhpUnit\DeprecationErrorHandler\Deprecation;
 
@@ -43,7 +45,7 @@ class DeprecationErrorHandler
     ];
 
     private static $isRegistered = false;
-    private static $utilPrefix;
+    private static $isAtLeastPhpUnit83;
 
     /**
      * Registers and configures the deprecation handler.
@@ -67,7 +69,7 @@ class DeprecationErrorHandler
             return;
         }
 
-        self::$utilPrefix = class_exists('PHPUnit_Util_ErrorHandler') ? 'PHPUnit_Util_' : 'PHPUnit\Util\\';
+        self::$isAtLeastPhpUnit83 = !class_exists('PHPUnit_Util_ErrorHandler') && method_exists(ErrorHandler::class, '__invoke');
 
         $handler = new self();
         $oldErrorHandler = set_error_handler([$handler, 'handleError']);
@@ -75,7 +77,7 @@ class DeprecationErrorHandler
         if (null !== $oldErrorHandler) {
             restore_error_handler();
 
-            if ([self::$utilPrefix.'ErrorHandler', 'handleError'] === $oldErrorHandler) {
+            if ($oldErrorHandler instanceof ErrorHandler || [ErrorHandler::class, 'handleError'] === $oldErrorHandler) {
                 restore_error_handler();
                 self::register($mode);
             }
@@ -95,12 +97,7 @@ class DeprecationErrorHandler
                     return $previousErrorHandler($type, $msg, $file, $line, $context);
                 }
 
-                static $autoload = true;
-
-                $ErrorHandler = class_exists('PHPUnit_Util_ErrorHandler', $autoload) ? 'PHPUnit_Util_ErrorHandler' : 'PHPUnit\Util\ErrorHandler';
-                $autoload = false;
-
-                return $ErrorHandler::handleError($type, $msg, $file, $line, $context);
+                return \call_user_func(self::getPhpUnitErrorHandler(), $type, $msg, $file, $line, $context);
             }
 
             $deprecations[] = [error_reporting(), $msg, $file];
@@ -117,9 +114,7 @@ class DeprecationErrorHandler
     public function handleError($type, $msg, $file, $line, $context = [])
     {
         if ((E_USER_DEPRECATED !== $type && E_DEPRECATED !== $type) || !$this->getConfiguration()->isEnabled()) {
-            $ErrorHandler = self::$utilPrefix.'ErrorHandler';
-
-            return $ErrorHandler::handleError($type, $msg, $file, $line, $context);
+            return \call_user_func(self::getPhpUnitErrorHandler(), $type, $msg, $file, $line, $context);
         }
 
         $deprecation = new Deprecation($msg, debug_backtrace(), $file);
@@ -135,7 +130,7 @@ class DeprecationErrorHandler
 
             if (0 !== error_reporting()) {
                 $group = 'unsilenced';
-            } elseif ($deprecation->isLegacy(self::$utilPrefix)) {
+            } elseif ($deprecation->isLegacy()) {
                 $group = 'legacy';
             } else {
                 $group = [
@@ -307,6 +302,26 @@ class DeprecationErrorHandler
         }
     }
 
+    private static function getPhpUnitErrorHandler()
+    {
+        if (!self::$isAtLeastPhpUnit83) {
+            return 'PHPUnit\Util\ErrorHandler::handleError';
+        }
+
+        foreach (debug_backtrace(DEBUG_BACKTRACE_PROVIDE_OBJECT | DEBUG_BACKTRACE_IGNORE_ARGS) as $frame) {
+            if (isset($frame['object']) && $frame['object'] instanceof TestResult) {
+                return new ErrorHandler(
+                    $frame['object']->getConvertDeprecationsToExceptions(),
+                    $frame['object']->getConvertErrorsToExceptions(),
+                    $frame['object']->getConvertNoticesToExceptions(),
+                    $frame['object']->getConvertWarningsToExceptions()
+                );
+            }
+        }
+
+        return function () { return false; };
+    }
+
     /**
      * Returns true if STDOUT is defined and supports colorization.
      *
diff --git a/src/Symfony/Bridge/PhpUnit/DeprecationErrorHandler/Deprecation.php b/src/Symfony/Bridge/PhpUnit/DeprecationErrorHandler/Deprecation.php
index 2d6aa29224..e5d2dc35d7 100644
--- a/src/Symfony/Bridge/PhpUnit/DeprecationErrorHandler/Deprecation.php
+++ b/src/Symfony/Bridge/PhpUnit/DeprecationErrorHandler/Deprecation.php
@@ -11,6 +11,7 @@
 
 namespace Symfony\Bridge\PhpUnit\DeprecationErrorHandler;
 
+use PHPUnit\Util\Test;
 use Symfony\Bridge\PhpUnit\Legacy\SymfonyTestsListenerFor;
 
 /**
@@ -156,9 +157,8 @@ class Deprecation
      *
      * @return bool
      */
-    public function isLegacy($utilPrefix)
+    public function isLegacy()
     {
-        $test = $utilPrefix.'Test';
         $class = $this->originatingClass();
         $method = $this->originatingMethod();
 
@@ -166,7 +166,7 @@ class Deprecation
             || 0 === strpos($method, 'provideLegacy')
             || 0 === strpos($method, 'getLegacy')
             || strpos($class, '\Legacy')
-            || \in_array('legacy', $test::getGroups($class, $method), true);
+            || \in_array('legacy', Test::getGroups($class, $method), true);
     }
 
     /**
diff --git a/src/Symfony/Bridge/PhpUnit/Legacy/CoverageListenerTrait.php b/src/Symfony/Bridge/PhpUnit/Legacy/CoverageListenerTrait.php
index 52d28cfbf8..1817004bf9 100644
--- a/src/Symfony/Bridge/PhpUnit/Legacy/CoverageListenerTrait.php
+++ b/src/Symfony/Bridge/PhpUnit/Legacy/CoverageListenerTrait.php
@@ -13,6 +13,7 @@ namespace Symfony\Bridge\PhpUnit\Legacy;
 
 use PHPUnit\Framework\TestCase;
 use PHPUnit\Framework\Warning;
+use PHPUnit\Util\Test;
 
 /**
  * PHP 5.3 compatible trait-like shared implementation.
@@ -65,12 +66,7 @@ class CoverageListenerTrait
             return;
         }
 
-        $testClass = \PHPUnit\Util\Test::class;
-        if (!class_exists($testClass, false)) {
-            $testClass = \PHPUnit_Util_Test::class;
-        }
-
-        $r = new \ReflectionProperty($testClass, 'annotationCache');
+        $r = new \ReflectionProperty(Test::class, 'annotationCache');
         $r->setAccessible(true);
 
         $cache = $r->getValue();
@@ -79,7 +75,7 @@ class CoverageListenerTrait
                 'covers' => \is_array($sutFqcn) ? $sutFqcn : array($sutFqcn),
             ),
         ));
-        $r->setValue($testClass, $cache);
+        $r->setValue(Test::class, $cache);
     }
 
     private function findSutFqcn($test)
diff --git a/src/Symfony/Bridge/PhpUnit/Legacy/PolyfillTestCaseTrait.php b/src/Symfony/Bridge/PhpUnit/Legacy/PolyfillTestCaseTrait.php
index 69609c5ea4..ebb9db2c94 100644
--- a/src/Symfony/Bridge/PhpUnit/Legacy/PolyfillTestCaseTrait.php
+++ b/src/Symfony/Bridge/PhpUnit/Legacy/PolyfillTestCaseTrait.php
@@ -15,7 +15,7 @@ use PHPUnit\Framework\MockObject\MockObject;
 use PHPUnit\Framework\TestCase;
 
 /**
- * This trait is @internal
+ * This trait is @internal.
  */
 trait PolyfillTestCaseTrait
 {
@@ -66,7 +66,7 @@ trait PolyfillTestCaseTrait
      */
     public function expectException($exception)
     {
-        $property = new \ReflectionProperty(class_exists('PHPUnit_Framework_TestCase') ? 'PHPUnit_Framework_TestCase' : TestCase::class, 'expectedException');
+        $property = new \ReflectionProperty(TestCase::class, 'expectedException');
         $property->setAccessible(true);
         $property->setValue($this, $exception);
     }
@@ -78,7 +78,7 @@ trait PolyfillTestCaseTrait
      */
     public function expectExceptionCode($code)
     {
-        $property = new \ReflectionProperty(class_exists('PHPUnit_Framework_TestCase') ? 'PHPUnit_Framework_TestCase' : TestCase::class, 'expectedExceptionCode');
+        $property = new \ReflectionProperty(TestCase::class, 'expectedExceptionCode');
         $property->setAccessible(true);
         $property->setValue($this, $code);
     }
@@ -90,7 +90,7 @@ trait PolyfillTestCaseTrait
      */
     public function expectExceptionMessage($message)
     {
-        $property = new \ReflectionProperty(class_exists('PHPUnit_Framework_TestCase') ? 'PHPUnit_Framework_TestCase' : TestCase::class, 'expectedExceptionMessage');
+        $property = new \ReflectionProperty(TestCase::class, 'expectedExceptionMessage');
         $property->setAccessible(true);
         $property->setValue($this, $message);
     }
@@ -102,7 +102,7 @@ trait PolyfillTestCaseTrait
      */
     public function expectExceptionMessageRegExp($messageRegExp)
     {
-        $property = new \ReflectionProperty(class_exists('PHPUnit_Framework_TestCase') ? 'PHPUnit_Framework_TestCase' : TestCase::class, 'expectedExceptionMessageRegExp');
+        $property = new \ReflectionProperty(TestCase::class, 'expectedExceptionMessageRegExp');
         $property->setAccessible(true);
         $property->setValue($this, $messageRegExp);
     }
diff --git a/src/Symfony/Bridge/PhpUnit/Legacy/SymfonyTestsListenerTrait.php b/src/Symfony/Bridge/PhpUnit/Legacy/SymfonyTestsListenerTrait.php
index 803f7114b8..0ac3ee4a1b 100644
--- a/src/Symfony/Bridge/PhpUnit/Legacy/SymfonyTestsListenerTrait.php
+++ b/src/Symfony/Bridge/PhpUnit/Legacy/SymfonyTestsListenerTrait.php
@@ -15,7 +15,9 @@ use Doctrine\Common\Annotations\AnnotationRegistry;
 use PHPUnit\Framework\AssertionFailedError;
 use PHPUnit\Framework\TestCase;
 use PHPUnit\Framework\TestSuite;
+use PHPUnit\Runner\BaseTestRunner;
 use PHPUnit\Util\Blacklist;
+use PHPUnit\Util\Test;
 use Symfony\Bridge\PhpUnit\ClockMock;
 use Symfony\Bridge\PhpUnit\DnsMock;
 use Symfony\Component\Debug\DebugClassLoader as LegacyDebugClassLoader;
@@ -48,11 +50,7 @@ class SymfonyTestsListenerTrait
      */
     public function __construct(array $mockedNamespaces = array())
     {
-        if (class_exists('PHPUnit_Util_Blacklist')) {
-            \PHPUnit_Util_Blacklist::$blacklistedClassNames['\Symfony\Bridge\PhpUnit\Legacy\SymfonyTestsListenerTrait'] = 2;
-        } else {
-            Blacklist::$blacklistedClassNames['\Symfony\Bridge\PhpUnit\Legacy\SymfonyTestsListenerTrait'] = 2;
-        }
+        Blacklist::$blacklistedClassNames['\Symfony\Bridge\PhpUnit\Legacy\SymfonyTestsListenerTrait'] = 2;
 
         $enableDebugClassLoader = class_exists(DebugClassLoader::class) || class_exists(LegacyDebugClassLoader::class);
 
@@ -113,11 +111,6 @@ class SymfonyTestsListenerTrait
 
     public function startTestSuite($suite)
     {
-        if (class_exists('PHPUnit_Util_Blacklist', false)) {
-            $Test = 'PHPUnit_Util_Test';
-        } else {
-            $Test = 'PHPUnit\Util\Test';
-        }
         $suiteName = $suite->getName();
         $this->testsWithWarnings = array();
 
@@ -125,7 +118,7 @@ class SymfonyTestsListenerTrait
             if (!($test instanceof \PHPUnit\Framework\TestCase || $test instanceof TestCase)) {
                 continue;
             }
-            if (null === $Test::getPreserveGlobalStateSettings(\get_class($test), $test->getName(false))) {
+            if (null === Test::getPreserveGlobalStateSettings(\get_class($test), $test->getName(false))) {
                 $test->setPreserveGlobalState(false);
             }
         }
@@ -157,12 +150,12 @@ class SymfonyTestsListenerTrait
             $testSuites = array($suite);
             for ($i = 0; isset($testSuites[$i]); ++$i) {
                 foreach ($testSuites[$i]->tests() as $test) {
-                    if ($test instanceof \PHPUnit_Framework_TestSuite || $test instanceof TestSuite) {
+                    if ($test instanceof TestSuite) {
                         if (!class_exists($test->getName(), false)) {
                             $testSuites[] = $test;
                             continue;
                         }
-                        $groups = $Test::getGroups($test->getName());
+                        $groups = Test::getGroups($test->getName());
                         if (\in_array('time-sensitive', $groups, true)) {
                             ClockMock::register($test->getName());
                         }
@@ -213,14 +206,7 @@ class SymfonyTestsListenerTrait
                 putenv('SYMFONY_DEPRECATIONS_SERIALIZE='.$this->runsInSeparateProcess);
             }
 
-            if (class_exists('PHPUnit_Util_Blacklist', false)) {
-                $Test = 'PHPUnit_Util_Test';
-                $AssertionFailedError = 'PHPUnit_Framework_AssertionFailedError';
-            } else {
-                $Test = 'PHPUnit\Util\Test';
-                $AssertionFailedError = 'PHPUnit\Framework\AssertionFailedError';
-            }
-            $groups = $Test::getGroups(\get_class($test), $test->getName(false));
+            $groups = Test::getGroups(\get_class($test), $test->getName(false));
 
             if (!$this->runsInSeparateProcess) {
                 if (\in_array('time-sensitive', $groups, true)) {
@@ -232,14 +218,14 @@ class SymfonyTestsListenerTrait
                 }
             }
 
-            $annotations = $Test::parseTestMethodAnnotations(\get_class($test), $test->getName(false));
+            $annotations = Test::parseTestMethodAnnotations(\get_class($test), $test->getName(false));
 
             if (isset($annotations['class']['expectedDeprecation'])) {
-                $test->getTestResultObject()->addError($test, new $AssertionFailedError('`@expectedDeprecation` annotations are not allowed at the class level.'), 0);
+                $test->getTestResultObject()->addError($test, new AssertionFailedError('`@expectedDeprecation` annotations are not allowed at the class level.'), 0);
             }
             if (isset($annotations['method']['expectedDeprecation'])) {
                 if (!\in_array('legacy', $groups, true)) {
-                    $this->error = new $AssertionFailedError('Only tests with the `@group legacy` annotation can have `@expectedDeprecation`.');
+                    $this->error = new AssertionFailedError('Only tests with the `@group legacy` annotation can have `@expectedDeprecation`.');
                 }
 
                 $test->getTestResultObject()->beStrictAboutTestsThatDoNotTestAnything(false);
@@ -259,18 +245,8 @@ class SymfonyTestsListenerTrait
 
     public function endTest($test, $time)
     {
-        if (class_exists('PHPUnit_Util_Blacklist', false)) {
-            $Test = 'PHPUnit_Util_Test';
-            $BaseTestRunner = 'PHPUnit_Runner_BaseTestRunner';
-            $Warning = 'PHPUnit_Framework_Warning';
-        } else {
-            $Test = 'PHPUnit\Util\Test';
-            $BaseTestRunner = 'PHPUnit\Runner\BaseTestRunner';
-            $Warning = 'PHPUnit\Framework\Warning';
-        }
         $className = \get_class($test);
-        $classGroups = $Test::getGroups($className);
-        $groups = $Test::getGroups($className, $test->getName(false));
+        $groups = Test::getGroups($className, $test->getName(false));
 
         if (null !== $this->reportUselessTests) {
             $test->getTestResultObject()->beStrictAboutTestsThatDoNotTestAnything($this->reportUselessTests);
@@ -299,20 +275,18 @@ class SymfonyTestsListenerTrait
         }
 
         if ($this->expectedDeprecations) {
-            if (!\in_array($test->getStatus(), array($BaseTestRunner::STATUS_SKIPPED, $BaseTestRunner::STATUS_INCOMPLETE), true)) {
+            if (!\in_array($test->getStatus(), array(BaseTestRunner::STATUS_SKIPPED, BaseTestRunner::STATUS_INCOMPLETE), true)) {
                 $test->addToAssertionCount(\count($this->expectedDeprecations));
             }
 
             restore_error_handler();
 
-            if (!$errored && !\in_array($test->getStatus(), array($BaseTestRunner::STATUS_SKIPPED, $BaseTestRunner::STATUS_INCOMPLETE, $BaseTestRunner::STATUS_FAILURE, $BaseTestRunner::STATUS_ERROR), true)) {
+            if (!$errored && !\in_array($test->getStatus(), array(BaseTestRunner::STATUS_SKIPPED, BaseTestRunner::STATUS_INCOMPLETE, BaseTestRunner::STATUS_FAILURE, BaseTestRunner::STATUS_ERROR), true)) {
                 try {
                     $prefix = "@expectedDeprecation:\n";
                     $test->assertStringMatchesFormat($prefix.'%A  '.implode("\n%A  ", $this->expectedDeprecations)."\n%A", $prefix.'  '.implode("\n  ", $this->gatheredDeprecations)."\n");
                 } catch (AssertionFailedError $e) {
                     $test->getTestResultObject()->addFailure($test, $e, $time);
-                } catch (\PHPUnit_Framework_AssertionFailedError $e) {
-                    $test->getTestResultObject()->addFailure($test, $e, $time);
                 }
             }
 
diff --git a/src/Symfony/Bridge/PhpUnit/SymfonyTestsListener.php b/src/Symfony/Bridge/PhpUnit/SymfonyTestsListener.php
index a753525b76..d3cd7563bd 100644
--- a/src/Symfony/Bridge/PhpUnit/SymfonyTestsListener.php
+++ b/src/Symfony/Bridge/PhpUnit/SymfonyTestsListener.php
@@ -11,7 +11,7 @@
 
 namespace Symfony\Bridge\PhpUnit;
 
-if (class_exists('PHPUnit_Runner_Version') && version_compare(\PHPUnit_Runner_Version::id(), '6.0.0', '<')) {
+if (version_compare(\PHPUnit\Runner\Version::id(), '6.0.0', '<')) {
     class_alias('Symfony\Bridge\PhpUnit\Legacy\SymfonyTestsListenerForV5', 'Symfony\Bridge\PhpUnit\SymfonyTestsListener');
 } elseif (version_compare(\PHPUnit\Runner\Version::id(), '7.0.0', '<')) {
     class_alias('Symfony\Bridge\PhpUnit\Legacy\SymfonyTestsListenerForV6', 'Symfony\Bridge\PhpUnit\SymfonyTestsListener');
diff --git a/src/Symfony/Bridge/PhpUnit/Tests/Fixtures/coverage/tests/bootstrap.php b/src/Symfony/Bridge/PhpUnit/Tests/Fixtures/coverage/tests/bootstrap.php
index 241006431a..3e45381dce 100644
--- a/src/Symfony/Bridge/PhpUnit/Tests/Fixtures/coverage/tests/bootstrap.php
+++ b/src/Symfony/Bridge/PhpUnit/Tests/Fixtures/coverage/tests/bootstrap.php
@@ -14,7 +14,7 @@ require __DIR__.'/../src/FooCov.php';
 
 require __DIR__.'/../../../../Legacy/CoverageListenerTrait.php';
 
-if (class_exists('PHPUnit_Runner_Version') && version_compare(\PHPUnit_Runner_Version::id(), '6.0.0', '<')) {
+if (version_compare(\PHPUnit\Runner\Version::id(), '6.0.0', '<')) {
     require_once __DIR__.'/../../../../Legacy/CoverageListenerForV5.php';
 } elseif (version_compare(\PHPUnit\Runner\Version::id(), '7.0.0', '<')) {
     require_once __DIR__.'/../../../../Legacy/CoverageListenerForV6.php';
diff --git a/src/Symfony/Bridge/PhpUnit/Tests/ProcessIsolationTest.php b/src/Symfony/Bridge/PhpUnit/Tests/ProcessIsolationTest.php
index b8125dc558..28277161b9 100644
--- a/src/Symfony/Bridge/PhpUnit/Tests/ProcessIsolationTest.php
+++ b/src/Symfony/Bridge/PhpUnit/Tests/ProcessIsolationTest.php
@@ -24,8 +24,7 @@ class ProcessIsolationTest extends TestCase
 
     public function testCallingOtherErrorHandler()
     {
-        $class = class_exists('PHPUnit\Framework\Exception') ? 'PHPUnit\Framework\Exception' : 'PHPUnit_Framework_Exception';
-        $this->expectException($class);
+        $this->expectException('PHPUnit\Framework\Exception');
         $this->expectExceptionMessage('Test that PHPUnit\'s error handler fires.');
 
         trigger_error('Test that PHPUnit\'s error handler fires.', E_USER_WARNING);
diff --git a/src/Symfony/Bridge/PhpUnit/TextUI/Command.php b/src/Symfony/Bridge/PhpUnit/TextUI/Command.php
index 4a26fc7fad..be73e4d2be 100644
--- a/src/Symfony/Bridge/PhpUnit/TextUI/Command.php
+++ b/src/Symfony/Bridge/PhpUnit/TextUI/Command.php
@@ -11,7 +11,7 @@
 
 namespace Symfony\Bridge\PhpUnit\TextUI;
 
-if (class_exists('PHPUnit_Runner_Version') && version_compare(\PHPUnit_Runner_Version::id(), '6.0.0', '<')) {
+if (version_compare(\PHPUnit\Runner\Version::id(), '6.0.0', '<')) {
     class_alias('Symfony\Bridge\PhpUnit\Legacy\CommandForV5', 'Symfony\Bridge\PhpUnit\TextUI\Command');
 } else {
     class_alias('Symfony\Bridge\PhpUnit\Legacy\CommandForV6', 'Symfony\Bridge\PhpUnit\TextUI\Command');
diff --git a/src/Symfony/Bridge/PhpUnit/bootstrap.php b/src/Symfony/Bridge/PhpUnit/bootstrap.php
index 5de9467891..26bde7335d 100644
--- a/src/Symfony/Bridge/PhpUnit/bootstrap.php
+++ b/src/Symfony/Bridge/PhpUnit/bootstrap.php
@@ -12,6 +12,95 @@
 use Doctrine\Common\Annotations\AnnotationRegistry;
 use Symfony\Bridge\PhpUnit\DeprecationErrorHandler;
 
+if (class_exists('PHPUnit_Runner_Version') && version_compare(\PHPUnit_Runner_Version::id(), '6.0.0', '<')) {
+    $classes = [
+        'PHPUnit_Framework_Assert', // override PhpUnit's ForwardCompat child class
+        'PHPUnit_Framework_AssertionFailedError', // override PhpUnit's ForwardCompat child class
+        'PHPUnit_Framework_BaseTestListener', // override PhpUnit's ForwardCompat child class
+
+        'PHPUnit_Framework_Constraint',
+        'PHPUnit_Framework_Constraint_And',
+        'PHPUnit_Framework_Constraint_ArrayHasKey',
+        'PHPUnit_Framework_Constraint_ArraySubset',
+        'PHPUnit_Framework_Constraint_Attribute',
+        'PHPUnit_Framework_Constraint_Callback',
+        'PHPUnit_Framework_Constraint_ClassHasAttribute',
+        'PHPUnit_Framework_Constraint_ClassHasStaticAttribute',
+        'PHPUnit_Framework_Constraint_Composite',
+        'PHPUnit_Framework_Constraint_Count',
+        'PHPUnit_Framework_Constraint_Exception',
+        'PHPUnit_Framework_Constraint_ExceptionCode',
+        'PHPUnit_Framework_Constraint_ExceptionMessage',
+        'PHPUnit_Framework_Constraint_ExceptionMessageRegExp',
+        'PHPUnit_Framework_Constraint_FileExists',
+        'PHPUnit_Framework_Constraint_GreaterThan',
+        'PHPUnit_Framework_Constraint_IsAnything',
+        'PHPUnit_Framework_Constraint_IsEmpty',
+        'PHPUnit_Framework_Constraint_IsEqual',
+        'PHPUnit_Framework_Constraint_IsFalse',
+        'PHPUnit_Framework_Constraint_IsIdentical',
+        'PHPUnit_Framework_Constraint_IsInstanceOf',
+        'PHPUnit_Framework_Constraint_IsJson',
+        'PHPUnit_Framework_Constraint_IsNull',
+        'PHPUnit_Framework_Constraint_IsTrue',
+        'PHPUnit_Framework_Constraint_IsType',
+        'PHPUnit_Framework_Constraint_JsonMatches',
+        'PHPUnit_Framework_Constraint_JsonMatches_ErrorMessageProvider',
+        'PHPUnit_Framework_Constraint_LessThan',
+        'PHPUnit_Framework_Constraint_Not',
+        'PHPUnit_Framework_Constraint_ObjectHasAttribute',
+        'PHPUnit_Framework_Constraint_Or',
+        'PHPUnit_Framework_Constraint_PCREMatch',
+        'PHPUnit_Framework_Constraint_SameSize',
+        'PHPUnit_Framework_Constraint_StringContains',
+        'PHPUnit_Framework_Constraint_StringEndsWith',
+        'PHPUnit_Framework_Constraint_StringMatches',
+        'PHPUnit_Framework_Constraint_StringStartsWith',
+        'PHPUnit_Framework_Constraint_TraversableContains',
+        'PHPUnit_Framework_Constraint_TraversableContainsOnly',
+        'PHPUnit_Framework_Constraint_Xor',
+
+        'PHPUnit_Framework_Error',
+        'PHPUnit_Framework_Error_Deprecated',
+        'PHPUnit_Framework_Error_Notice',
+        'PHPUnit_Framework_Error_Warning',
+        'PHPUnit_Framework_Exception',
+        'PHPUnit_Framework_ExpectationFailedException',
+
+        'PHPUnit_Framework_MockObject_MockObject',
+
+        'PHPUnit_Framework_IncompleteTest',
+        'PHPUnit_Framework_IncompleteTestCase',
+        'PHPUnit_Framework_IncompleteTestError',
+        'PHPUnit_Framework_RiskyTest',
+        'PHPUnit_Framework_RiskyTestError',
+        'PHPUnit_Framework_SkippedTest',
+        'PHPUnit_Framework_SkippedTestCase',
+        'PHPUnit_Framework_SkippedTestError',
+        'PHPUnit_Framework_SkippedTestSuiteError',
+
+        'PHPUnit_Framework_SyntheticError',
+
+        'PHPUnit_Framework_Test',
+        'PHPUnit_Framework_TestCase', // override PhpUnit's ForwardCompat child class
+        'PHPUnit_Framework_TestFailure',
+        'PHPUnit_Framework_TestListener',
+        'PHPUnit_Framework_TestResult',
+        'PHPUnit_Framework_TestSuite', // override PhpUnit's ForwardCompat child class
+
+        'PHPUnit_Runner_BaseTestRunner',
+        'PHPUnit_Runner_Version',
+
+        'PHPUnit_Util_Blacklist',
+        'PHPUnit_Util_ErrorHandler',
+        'PHPUnit_Util_Test',
+        'PHPUnit_Util_XML',
+    ];
+    foreach ($classes as $class) {
+        class_alias($class, '\\'.strtr($class, '_', '\\'), true);
+    }
+}
+
 // Detect if we need to serialize deprecations to a file.
 if ($file = getenv('SYMFONY_DEPRECATIONS_SERIALIZE')) {
     DeprecationErrorHandler::collectDeprecations($file);
diff --git a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php
index 111ba6baba..19b8ca9d44 100644
--- a/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php
+++ b/src/Symfony/Bundle/FrameworkBundle/DependencyInjection/Configuration.php
@@ -1369,7 +1369,7 @@ class Configuration implements ConfigurationInterface
                                         ->info('A comma separated list of hosts that do not require a proxy to be reached.')
                                     ->end()
                                     ->floatNode('timeout')
-                                        ->info('Defaults to "default_socket_timeout" ini parameter.')
+                                        ->info('The idle timeout, defaults to the "default_socket_timeout" ini parameter.')
                                     ->end()
                                     ->scalarNode('bindto')
                                         ->info('A network interface name, IP address, a host name or a UNIX socket to bind to.')
diff --git a/src/Symfony/Bundle/FrameworkBundle/Resources/config/mailer.xml b/src/Symfony/Bundle/FrameworkBundle/Resources/config/mailer.xml
index becf0d1b71..fa10ebaae3 100644
--- a/src/Symfony/Bundle/FrameworkBundle/Resources/config/mailer.xml
+++ b/src/Symfony/Bundle/FrameworkBundle/Resources/config/mailer.xml
@@ -8,6 +8,7 @@
         <service id="mailer.mailer" class="Symfony\Component\Mailer\Mailer">
             <argument type="service" id="mailer.default_transport" />
             <argument type="service" id="messenger.default_bus" on-invalid="ignore" />
+            <argument type="service" id="event_dispatcher" on-invalid="ignore" />
         </service>
         <service id="mailer" alias="mailer.mailer" />
         <service id="Symfony\Component\Mailer\MailerInterface" alias="mailer.mailer" />
diff --git a/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/FrameworkExtensionTest.php b/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/FrameworkExtensionTest.php
index 8c1ef9d145..fdc57dca19 100644
--- a/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/FrameworkExtensionTest.php
+++ b/src/Symfony/Bundle/FrameworkBundle/Tests/DependencyInjection/FrameworkExtensionTest.php
@@ -54,7 +54,6 @@ use Symfony\Component\Translation\DependencyInjection\TranslatorPass;
 use Symfony\Component\Validator\DependencyInjection\AddConstraintValidatorsPass;
 use Symfony\Component\Validator\Mapping\Loader\PropertyInfoLoader;
 use Symfony\Component\Workflow;
-use Symfony\Contracts\Translation\TranslatorInterface;
 
 abstract class FrameworkExtensionTest extends TestCase
 {
diff --git a/src/Symfony/Bundle/SecurityBundle/Resources/config/guard.xml b/src/Symfony/Bundle/SecurityBundle/Resources/config/guard.xml
index 43321494e0..7b17aff868 100644
--- a/src/Symfony/Bundle/SecurityBundle/Resources/config/guard.xml
+++ b/src/Symfony/Bundle/SecurityBundle/Resources/config/guard.xml
@@ -29,6 +29,7 @@
             <argument /> <!-- User Provider -->
             <argument /> <!-- Provider-shared Key -->
             <argument /> <!-- User Checker -->
+            <argument type="service" id="security.password_encoder" />
         </service>
 
         <service id="security.authentication.listener.guard"
diff --git a/src/Symfony/Component/DependencyInjection/Tests/Compiler/ResolveInstanceofConditionalsPassTest.php b/src/Symfony/Component/DependencyInjection/Tests/Compiler/ResolveInstanceofConditionalsPassTest.php
index 656aee9cfb..ebd8f3df10 100644
--- a/src/Symfony/Component/DependencyInjection/Tests/Compiler/ResolveInstanceofConditionalsPassTest.php
+++ b/src/Symfony/Component/DependencyInjection/Tests/Compiler/ResolveInstanceofConditionalsPassTest.php
@@ -233,7 +233,7 @@ class ResolveInstanceofConditionalsPassTest extends TestCase
     public function testProcessThrowsExceptionForArguments()
     {
         $this->expectException('Symfony\Component\DependencyInjection\Exception\InvalidArgumentException');
-        $this->expectExceptionMessage('Autoconfigured instanceof for type "PHPUnit\Framework\TestCase" defines arguments but these are not supported and should be removed.');
+        $this->expectExceptionMessageRegExp('/Autoconfigured instanceof for type "PHPUnit[\\\\_]Framework[\\\\_]TestCase" defines arguments but these are not supported and should be removed\./');
         $container = new ContainerBuilder();
         $container->registerForAutoconfiguration(parent::class)
             ->addArgument('bar');
diff --git a/src/Symfony/Component/DependencyInjection/Tests/Config/ContainerParametersResourceCheckerTest.php b/src/Symfony/Component/DependencyInjection/Tests/Config/ContainerParametersResourceCheckerTest.php
index 867ab7f304..51af451c16 100644
--- a/src/Symfony/Component/DependencyInjection/Tests/Config/ContainerParametersResourceCheckerTest.php
+++ b/src/Symfony/Component/DependencyInjection/Tests/Config/ContainerParametersResourceCheckerTest.php
@@ -11,6 +11,7 @@
 
 namespace Symfony\Component\DependencyInjection\Tests\Config;
 
+use PHPUnit\Framework\MockObject\MockObject;
 use PHPUnit\Framework\TestCase;
 use Symfony\Component\Config\ResourceCheckerInterface;
 use Symfony\Component\DependencyInjection\Config\ContainerParametersResource;
@@ -52,15 +53,15 @@ class ContainerParametersResourceCheckerTest extends TestCase
 
     public function isFreshProvider()
     {
-        yield 'not fresh on missing parameter' => [function (\PHPUnit\Framework\MockObject\MockObject $container) {
+        yield 'not fresh on missing parameter' => [function (MockObject $container) {
             $container->method('hasParameter')->with('locales')->willReturn(false);
         }, false];
 
-        yield 'not fresh on different value' => [function (\PHPUnit\Framework\MockObject\MockObject $container) {
+        yield 'not fresh on different value' => [function (MockObject $container) {
             $container->method('getParameter')->with('locales')->willReturn(['nl', 'es']);
         }, false];
 
-        yield 'fresh on every identical parameters' => [function (\PHPUnit\Framework\MockObject\MockObject $container) {
+        yield 'fresh on every identical parameters' => [function (MockObject $container) {
             $container->expects($this->exactly(2))->method('hasParameter')->willReturn(true);
             $container->expects($this->exactly(2))->method('getParameter')
                 ->withConsecutive(
diff --git a/src/Symfony/Component/ErrorRenderer/Tests/Exception/FlattenExceptionTest.php b/src/Symfony/Component/ErrorRenderer/Tests/Exception/FlattenExceptionTest.php
index 0220d75b9e..0420469891 100644
--- a/src/Symfony/Component/ErrorRenderer/Tests/Exception/FlattenExceptionTest.php
+++ b/src/Symfony/Component/ErrorRenderer/Tests/Exception/FlattenExceptionTest.php
@@ -294,7 +294,7 @@ class FlattenExceptionTest extends TestCase
 
         // assertEquals() does not like NAN values.
         $this->assertEquals($array[$i][0], 'float');
-        $this->assertTrue(is_nan($array[$i++][1]));
+        $this->assertNan($array[$i++][1]);
     }
 
     public function testRecursionInArguments()
diff --git a/src/Symfony/Component/Filesystem/Tests/FilesystemTest.php b/src/Symfony/Component/Filesystem/Tests/FilesystemTest.php
index 258aea5954..bb1484ab67 100644
--- a/src/Symfony/Component/Filesystem/Tests/FilesystemTest.php
+++ b/src/Symfony/Component/Filesystem/Tests/FilesystemTest.php
@@ -153,7 +153,7 @@ class FilesystemTest extends FilesystemTestCase
 
         $this->filesystem->copy($sourceFilePath, $targetFilePath);
 
-        $this->assertTrue(is_dir($targetFileDirectory));
+        $this->assertDirectoryExists($targetFileDirectory);
         $this->assertFileExists($targetFilePath);
         $this->assertStringEqualsFile($targetFilePath, 'SOURCE FILE');
     }
@@ -185,7 +185,7 @@ class FilesystemTest extends FilesystemTestCase
 
         $this->filesystem->mkdir($directory);
 
-        $this->assertTrue(is_dir($directory));
+        $this->assertDirectoryExists($directory);
     }
 
     public function testMkdirCreatesDirectoriesFromArray()
@@ -197,9 +197,9 @@ class FilesystemTest extends FilesystemTestCase
 
         $this->filesystem->mkdir($directories);
 
-        $this->assertTrue(is_dir($basePath.'1'));
-        $this->assertTrue(is_dir($basePath.'2'));
-        $this->assertTrue(is_dir($basePath.'3'));
+        $this->assertDirectoryExists($basePath.'1');
+        $this->assertDirectoryExists($basePath.'2');
+        $this->assertDirectoryExists($basePath.'3');
     }
 
     public function testMkdirCreatesDirectoriesFromTraversableObject()
@@ -211,9 +211,9 @@ class FilesystemTest extends FilesystemTestCase
 
         $this->filesystem->mkdir($directories);
 
-        $this->assertTrue(is_dir($basePath.'1'));
-        $this->assertTrue(is_dir($basePath.'2'));
-        $this->assertTrue(is_dir($basePath.'3'));
+        $this->assertDirectoryExists($basePath.'1');
+        $this->assertDirectoryExists($basePath.'2');
+        $this->assertDirectoryExists($basePath.'3');
     }
 
     public function testMkdirCreatesDirectoriesFails()
@@ -347,7 +347,7 @@ class FilesystemTest extends FilesystemTestCase
 
         // create symlink to dir using trailing forward slash
         $this->filesystem->symlink($basePath.'dir/', $basePath.'dir-link');
-        $this->assertTrue(is_dir($basePath.'dir-link'));
+        $this->assertDirectoryExists($basePath.'dir-link');
 
         // create symlink to nonexistent dir
         rmdir($basePath.'dir');
@@ -807,7 +807,7 @@ class FilesystemTest extends FilesystemTestCase
 
         $this->assertFalse(is_link($link));
         $this->assertFalse(is_file($link));
-        $this->assertFalse(is_dir($link));
+        $this->assertDirectoryNotExists($link);
     }
 
     public function testSymlinkIsOverwrittenIfPointsToDifferentTarget()
@@ -1136,8 +1136,8 @@ class FilesystemTest extends FilesystemTestCase
 
         $this->filesystem->mirror($sourcePath, $targetPath);
 
-        $this->assertTrue(is_dir($targetPath));
-        $this->assertTrue(is_dir($targetPath.'directory'));
+        $this->assertDirectoryExists($targetPath);
+        $this->assertDirectoryExists($targetPath.'directory');
         $this->assertFileEquals($file1, $targetPath.'directory'.\DIRECTORY_SEPARATOR.'file1');
         $this->assertFileEquals($file2, $targetPath.'file2');
 
@@ -1170,7 +1170,7 @@ class FilesystemTest extends FilesystemTestCase
 
         $this->filesystem->mirror($sourcePath, $targetPath);
 
-        $this->assertTrue(is_dir($targetPath));
+        $this->assertDirectoryExists($targetPath);
 
         $this->filesystem->remove($sourcePath);
     }
@@ -1189,7 +1189,7 @@ class FilesystemTest extends FilesystemTestCase
 
         $this->filesystem->mirror($sourcePath, $targetPath);
 
-        $this->assertTrue(is_dir($targetPath));
+        $this->assertDirectoryExists($targetPath);
         $this->assertFileEquals($sourcePath.'file1', $targetPath.'link1');
         $this->assertTrue(is_link($targetPath.\DIRECTORY_SEPARATOR.'link1'));
     }
@@ -1209,7 +1209,7 @@ class FilesystemTest extends FilesystemTestCase
 
         $this->filesystem->mirror($sourcePath, $targetPath);
 
-        $this->assertTrue(is_dir($targetPath));
+        $this->assertDirectoryExists($targetPath);
         $this->assertFileEquals($sourcePath.'/nested/file1.txt', $targetPath.'link1/file1.txt');
         $this->assertTrue(is_link($targetPath.\DIRECTORY_SEPARATOR.'link1'));
     }
@@ -1233,7 +1233,7 @@ class FilesystemTest extends FilesystemTestCase
 
         $this->filesystem->mirror($sourcePath, $targetPath);
 
-        $this->assertTrue(is_dir($targetPath));
+        $this->assertDirectoryExists($targetPath);
         $this->assertFileEquals($sourcePath.'/nested/file1.txt', $targetPath.'link1/file1.txt');
         $this->assertTrue(is_link($targetPath.\DIRECTORY_SEPARATOR.'link1'));
         $this->assertEquals('\\' === \DIRECTORY_SEPARATOR ? realpath($sourcePath.'\nested') : 'nested', readlink($targetPath.\DIRECTORY_SEPARATOR.'link1'));
@@ -1256,7 +1256,7 @@ class FilesystemTest extends FilesystemTestCase
 
         chdir($oldPath);
 
-        $this->assertTrue(is_dir($targetPath));
+        $this->assertDirectoryExists($targetPath);
         $this->assertFileExists($targetPath.'source');
         $this->assertFileExists($targetPath.'target');
     }
@@ -1281,7 +1281,7 @@ class FilesystemTest extends FilesystemTestCase
 
         chdir($oldPath);
 
-        $this->assertTrue(is_dir($targetPath));
+        $this->assertDirectoryExists($targetPath);
         $this->assertFileExists($targetPath.'source');
         $this->assertFileNotExists($targetPath.'target');
     }
diff --git a/src/Symfony/Component/Finder/Tests/FinderTest.php b/src/Symfony/Component/Finder/Tests/FinderTest.php
index 0e7e82b28b..e26aef1666 100644
--- a/src/Symfony/Component/Finder/Tests/FinderTest.php
+++ b/src/Symfony/Component/Finder/Tests/FinderTest.php
@@ -1365,11 +1365,7 @@ class FinderTest extends Iterator\RealIteratorTestCase
             } catch (\Exception $e) {
                 $expectedExceptionClass = 'Symfony\\Component\\Finder\\Exception\\AccessDeniedException';
                 if ($e instanceof \PHPUnit\Framework\ExpectationFailedException) {
-                    $this->fail(sprintf("Expected exception:\n%s\nGot:\n%s\nWith comparison failure:\n%s", $expectedExceptionClass, 'PHPUnit_Framework_ExpectationFailedException', $e->getComparisonFailure()->getExpectedAsString()));
-                }
-
-                if ($e instanceof \PHPUnit\Framework\ExpectationFailedException) {
-                    $this->fail(sprintf("Expected exception:\n%s\nGot:\n%s\nWith comparison failure:\n%s", $expectedExceptionClass, '\PHPUnit\Framework\ExpectationFailedException', $e->getComparisonFailure()->getExpectedAsString()));
+                    $this->fail(sprintf("Expected exception:\n%s\nGot:\n%s\nWith comparison failure:\n%s", $expectedExceptionClass, 'PHPUnit\Framework\ExpectationFailedException', $e->getComparisonFailure()->getExpectedAsString()));
                 }
 
                 $this->assertInstanceOf($expectedExceptionClass, $e);
diff --git a/src/Symfony/Component/Form/Button.php b/src/Symfony/Component/Form/Button.php
index ed1106b467..50acb8db0c 100644
--- a/src/Symfony/Component/Form/Button.php
+++ b/src/Symfony/Component/Form/Button.php
@@ -38,8 +38,6 @@ class Button implements \IteratorAggregate, FormInterface
 
     /**
      * Creates a new button from a form configuration.
-     *
-     * @param FormConfigInterface $config The button's configuration
      */
     public function __construct(FormConfigInterface $config)
     {
@@ -128,10 +126,6 @@ class Button implements \IteratorAggregate, FormInterface
      *
      * This method should not be invoked.
      *
-     * @param int|string|FormInterface $child
-     * @param null                     $type
-     * @param array                    $options
-     *
      * @throws BadMethodCallException
      */
     public function add($child, $type = null, array $options = [])
diff --git a/src/Symfony/Component/HttpClient/Response/MockResponse.php b/src/Symfony/Component/HttpClient/Response/MockResponse.php
index 90bb0df339..fe94bc3436 100644
--- a/src/Symfony/Component/HttpClient/Response/MockResponse.php
+++ b/src/Symfony/Component/HttpClient/Response/MockResponse.php
@@ -37,7 +37,7 @@ class MockResponse implements ResponseInterface
 
     /**
      * @param string|string[]|iterable $body The response body as a string or an iterable of strings,
-     *                                       yielding an empty string simulates a timeout,
+     *                                       yielding an empty string simulates an idle timeout,
      *                                       exceptions are turned to TransportException
      *
      * @see ResponseInterface::getInfo() for possible info, e.g. "response_headers"
@@ -277,7 +277,7 @@ class MockResponse implements ResponseInterface
         if (!\is_string($body)) {
             foreach ($body as $chunk) {
                 if ('' === $chunk = (string) $chunk) {
-                    // simulate a timeout
+                    // simulate an idle timeout
                     $response->body[] = new ErrorChunk($offset);
                 } else {
                     $response->body[] = $chunk;
diff --git a/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/Handler/NativeFileSessionHandlerTest.php b/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/Handler/NativeFileSessionHandlerTest.php
index 375749e476..cd167fb13a 100644
--- a/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/Handler/NativeFileSessionHandlerTest.php
+++ b/src/Symfony/Component/HttpFoundation/Tests/Session/Storage/Handler/NativeFileSessionHandlerTest.php
@@ -42,7 +42,7 @@ class NativeFileSessionHandlerTest extends TestCase
     {
         $handler = new NativeFileSessionHandler($savePath);
         $this->assertEquals($expectedSavePath, ini_get('session.save_path'));
-        $this->assertTrue(is_dir(realpath($path)));
+        $this->assertDirectoryExists(realpath($path));
 
         rmdir($path);
     }
diff --git a/src/Symfony/Component/HttpKernel/Tests/DependencyInjection/RemoveEmptyControllerArgumentLocatorsPassTest.php b/src/Symfony/Component/HttpKernel/Tests/DependencyInjection/RemoveEmptyControllerArgumentLocatorsPassTest.php
index 56fe6baf76..b5e55bdea9 100644
--- a/src/Symfony/Component/HttpKernel/Tests/DependencyInjection/RemoveEmptyControllerArgumentLocatorsPassTest.php
+++ b/src/Symfony/Component/HttpKernel/Tests/DependencyInjection/RemoveEmptyControllerArgumentLocatorsPassTest.php
@@ -26,7 +26,7 @@ class RemoveEmptyControllerArgumentLocatorsPassTest extends TestCase
         $resolver = $container->register('argument_resolver.service')->addArgument([]);
 
         $container->register('stdClass', 'stdClass');
-        $container->register(parent::class, 'stdClass');
+        $container->register(TestCase::class, 'stdClass');
         $container->register('c1', RemoveTestController1::class)->addTag('controller.service_arguments');
         $container->register('c2', RemoveTestController2::class)->addTag('controller.service_arguments')
             ->addMethodCall('setTestCase', [new Reference('c1')]);
diff --git a/src/Symfony/Component/Intl/Countries.php b/src/Symfony/Component/Intl/Countries.php
index 5f2642aa08..07812f5131 100644
--- a/src/Symfony/Component/Intl/Countries.php
+++ b/src/Symfony/Component/Intl/Countries.php
@@ -31,13 +31,16 @@ final class Countries extends ResourceBundle
      *
      * This list only contains "officially assigned ISO 3166-1 alpha-2" country codes.
      *
-     * @return string[] an array of canonical ISO 3166 country codes
+     * @return string[] an array of canonical ISO 3166 alpha-2 country codes
      */
     public static function getCountryCodes(): array
     {
         return self::readEntry(['Regions'], 'meta');
     }
 
+    /**
+     * @param string $country Alpha2 country code
+     */
     public static function exists(string $country): bool
     {
         try {
@@ -50,6 +53,8 @@ final class Countries extends ResourceBundle
     }
 
     /**
+     * Gets the country name from alpha2 code.
+     *
      * @throws MissingResourceException if the country code does not exists
      */
     public static function getName(string $country, string $displayLocale = null): string
@@ -58,6 +63,8 @@ final class Countries extends ResourceBundle
     }
 
     /**
+     * Gets the list of country names indexed with alpha2 codes as keys.
+     *
      * @return string[]
      */
     public static function getNames($displayLocale = null): array
diff --git a/src/Symfony/Component/Intl/DateFormatter/IntlDateFormatter.php b/src/Symfony/Component/Intl/DateFormatter/IntlDateFormatter.php
index 0db8230839..390a98b962 100644
--- a/src/Symfony/Component/Intl/DateFormatter/IntlDateFormatter.php
+++ b/src/Symfony/Component/Intl/DateFormatter/IntlDateFormatter.php
@@ -176,7 +176,7 @@ class IntlDateFormatter
     /**
      * Format the date/time value (timestamp) as a string.
      *
-     * @param int|\DateTime $timestamp The timestamp to format
+     * @param int|\DateTimeInterface $timestamp The timestamp to format
      *
      * @return string|bool The formatted value or false if formatting failed
      *
@@ -195,7 +195,7 @@ class IntlDateFormatter
 
         // behave like the intl extension
         $argumentError = null;
-        if (!\is_int($timestamp) && !$timestamp instanceof \DateTime) {
+        if (!\is_int($timestamp) && !$timestamp instanceof \DateTimeInterface) {
             $argumentError = sprintf('datefmt_format: string \'%s\' is not numeric, which would be required for it to be a valid date', $timestamp);
         }
 
@@ -207,7 +207,7 @@ class IntlDateFormatter
             return false;
         }
 
-        if ($timestamp instanceof \DateTime) {
+        if ($timestamp instanceof \DateTimeInterface) {
             $timestamp = $timestamp->getTimestamp();
         }
 
diff --git a/src/Symfony/Component/Intl/Languages.php b/src/Symfony/Component/Intl/Languages.php
index 127f15f3e8..a70a7e8b9c 100644
--- a/src/Symfony/Component/Intl/Languages.php
+++ b/src/Symfony/Component/Intl/Languages.php
@@ -22,7 +22,7 @@ use Symfony\Component\Intl\Exception\MissingResourceException;
 final class Languages extends ResourceBundle
 {
     /**
-     * Returns all available languages.
+     * Returns all available languages as two-letter codes.
      *
      * Languages are returned as lowercase ISO 639-1 two-letter language codes.
      * For languages that don't have a two-letter code, the ISO 639-2
@@ -31,7 +31,7 @@ final class Languages extends ResourceBundle
      * A full table of ISO 639 language codes can be found here:
      * http://www-01.sil.org/iso639-3/codes.asp
      *
-     * @return string[] an array of canonical ISO 639 language codes
+     * @return string[] an array of canonical ISO 639-1 language codes
      */
     public static function getLanguageCodes(): array
     {
@@ -50,6 +50,8 @@ final class Languages extends ResourceBundle
     }
 
     /**
+     * Gets the language name from alpha2 code.
+     *
      * @throws MissingResourceException if the language code does not exists
      */
     public static function getName(string $language, string $displayLocale = null): string
@@ -58,6 +60,8 @@ final class Languages extends ResourceBundle
     }
 
     /**
+     * Gets the list of language names indexed with alpha2 codes as keys.
+     *
      * @return string[]
      */
     public static function getNames(string $displayLocale = null): array
@@ -66,7 +70,7 @@ final class Languages extends ResourceBundle
     }
 
     /**
-     * Returns the ISO 639-2 three-letter code of a language.
+     * Returns the ISO 639-2 three-letter code of a language, given a two-letter code.
      *
      * @throws MissingResourceException if the language has no corresponding three-letter code
      */
diff --git a/src/Symfony/Component/Intl/Tests/DateFormatter/AbstractIntlDateFormatterTest.php b/src/Symfony/Component/Intl/Tests/DateFormatter/AbstractIntlDateFormatterTest.php
index 110fd63f7a..438c9c354c 100644
--- a/src/Symfony/Component/Intl/Tests/DateFormatter/AbstractIntlDateFormatterTest.php
+++ b/src/Symfony/Component/Intl/Tests/DateFormatter/AbstractIntlDateFormatterTest.php
@@ -76,6 +76,7 @@ abstract class AbstractIntlDateFormatterTest extends TestCase
     public function formatProvider()
     {
         $dateTime = new \DateTime('@0');
+        $dateTimeImmutable = new \DateTimeImmutable('@0');
 
         $formatData = [
             /* general */
@@ -250,6 +251,12 @@ abstract class AbstractIntlDateFormatterTest extends TestCase
         $formatData[] = ['h:mm a', $dateTime, '12:00 AM'];
         $formatData[] = ['yyyyy.MMMM.dd hh:mm aaa', $dateTime, '01970.January.01 12:00 AM'];
 
+        /* general, DateTimeImmutable */
+        $formatData[] = ['y-M-d', $dateTimeImmutable, '1970-1-1'];
+        $formatData[] = ["EEE, MMM d, ''yy", $dateTimeImmutable, "Thu, Jan 1, '70"];
+        $formatData[] = ['h:mm a', $dateTimeImmutable, '12:00 AM'];
+        $formatData[] = ['yyyyy.MMMM.dd hh:mm aaa', $dateTimeImmutable, '01970.January.01 12:00 AM'];
+
         if (IcuVersion::compare(Intl::getIcuVersion(), '59.1', '>=', 1)) {
             // Before ICU 59.1 GMT was used instead of UTC
             $formatData[] = ["yyyy.MM.dd 'at' HH:mm:ss zzz", 0, '1970.01.01 at 00:00:00 UTC'];
@@ -269,6 +276,8 @@ abstract class AbstractIntlDateFormatterTest extends TestCase
 
         $this->assertSame('1970.01.01 at 00:00:00 GMT', $gmtFormatter->format(new \DateTime('@0')));
         $this->assertSame('1970.01.01 at 00:00:00 UTC', $utcFormatter->format(new \DateTime('@0')));
+        $this->assertSame('1970.01.01 at 00:00:00 GMT', $gmtFormatter->format(new \DateTimeImmutable('@0')));
+        $this->assertSame('1970.01.01 at 00:00:00 UTC', $utcFormatter->format(new \DateTimeImmutable('@0')));
     }
 
     /**
diff --git a/src/Symfony/Component/Intl/Tests/IntlTest.php b/src/Symfony/Component/Intl/Tests/IntlTest.php
index b8d2c29e52..6510f9e626 100644
--- a/src/Symfony/Component/Intl/Tests/IntlTest.php
+++ b/src/Symfony/Component/Intl/Tests/IntlTest.php
@@ -41,6 +41,6 @@ class IntlTest extends TestCase
 
     public function testGetDataDirectoryReturnsThePathToIcuData()
     {
-        $this->assertTrue(is_dir(Intl::getDataDirectory()));
+        $this->assertDirectoryExists(Intl::getDataDirectory());
     }
 }
diff --git a/src/Symfony/Component/Intl/Tests/LanguagesTest.php b/src/Symfony/Component/Intl/Tests/LanguagesTest.php
index 5da1060cc3..296f3b2eee 100644
--- a/src/Symfony/Component/Intl/Tests/LanguagesTest.php
+++ b/src/Symfony/Component/Intl/Tests/LanguagesTest.php
@@ -644,11 +644,9 @@ class LanguagesTest extends ResourceBundleTestCase
         'ab' => 'abk',
         'af' => 'afr',
         'ak' => 'aka',
-        'sq' => 'sqi',
         'am' => 'amh',
         'ar' => 'ara',
         'an' => 'arg',
-        'hy' => 'hye',
         'as' => 'asm',
         'av' => 'ava',
         'ae' => 'ave',
@@ -656,7 +654,6 @@ class LanguagesTest extends ResourceBundleTestCase
         'az' => 'aze',
         'ba' => 'bak',
         'bm' => 'bam',
-        'eu' => 'eus',
         'be' => 'bel',
         'bn' => 'ben',
         'bi' => 'bis',
@@ -664,12 +661,10 @@ class LanguagesTest extends ResourceBundleTestCase
         'bs' => 'bos',
         'br' => 'bre',
         'bg' => 'bul',
-        'my' => 'mya',
         'ca' => 'cat',
         'cs' => 'ces',
         'ch' => 'cha',
         'ce' => 'che',
-        'zh' => 'zho',
         'cu' => 'chu',
         'cv' => 'chv',
         'kw' => 'cor',
@@ -679,13 +674,12 @@ class LanguagesTest extends ResourceBundleTestCase
         'da' => 'dan',
         'de' => 'deu',
         'dv' => 'div',
-        'nl' => 'nld',
         'dz' => 'dzo',
-        'et' => 'est',
         'el' => 'ell',
         'en' => 'eng',
         'eo' => 'epo',
-        'ik' => 'ipk',
+        'et' => 'est',
+        'eu' => 'eus',
         'ee' => 'ewe',
         'fo' => 'fao',
         'fa' => 'fas',
@@ -694,8 +688,6 @@ class LanguagesTest extends ResourceBundleTestCase
         'fr' => 'fra',
         'fy' => 'fry',
         'ff' => 'ful',
-        'om' => 'orm',
-        'ka' => 'kat',
         'gd' => 'gla',
         'ga' => 'gle',
         'gl' => 'glg',
@@ -710,32 +702,34 @@ class LanguagesTest extends ResourceBundleTestCase
         'ho' => 'hmo',
         'hr' => 'hrv',
         'hu' => 'hun',
+        'hy' => 'hye',
         'ig' => 'ibo',
-        'is' => 'isl',
         'io' => 'ido',
         'ii' => 'iii',
         'iu' => 'iku',
         'ie' => 'ile',
         'ia' => 'ina',
         'id' => 'ind',
+        'ik' => 'ipk',
+        'is' => 'isl',
         'it' => 'ita',
         'jv' => 'jav',
         'ja' => 'jpn',
         'kl' => 'kal',
         'kn' => 'kan',
         'ks' => 'kas',
+        'ka' => 'kat',
         'kr' => 'kau',
         'kk' => 'kaz',
-        'mn' => 'mon',
         'km' => 'khm',
         'ki' => 'kik',
         'rw' => 'kin',
         'ky' => 'kir',
-        'ku' => 'kur',
-        'kg' => 'kon',
         'kv' => 'kom',
+        'kg' => 'kon',
         'ko' => 'kor',
         'kj' => 'kua',
+        'ku' => 'kur',
         'lo' => 'lao',
         'la' => 'lat',
         'lv' => 'lav',
@@ -745,32 +739,36 @@ class LanguagesTest extends ResourceBundleTestCase
         'lb' => 'ltz',
         'lu' => 'lub',
         'lg' => 'lug',
-        'mk' => 'mkd',
         'mh' => 'mah',
         'ml' => 'mal',
-        'mi' => 'mri',
         'mr' => 'mar',
-        'ms' => 'msa',
+        'mk' => 'mkd',
         'mg' => 'mlg',
         'mt' => 'mlt',
+        'mn' => 'mon',
+        'mi' => 'mri',
+        'ms' => 'msa',
+        'my' => 'mya',
         'na' => 'nau',
         'nv' => 'nav',
         'nr' => 'nbl',
         'nd' => 'nde',
         'ng' => 'ndo',
         'ne' => 'nep',
+        'nl' => 'nld',
         'nn' => 'nno',
         'nb' => 'nob',
         'ny' => 'nya',
         'oc' => 'oci',
         'oj' => 'oji',
         'or' => 'ori',
+        'om' => 'orm',
         'os' => 'oss',
         'pa' => 'pan',
-        'ps' => 'pus',
         'pi' => 'pli',
         'pl' => 'pol',
         'pt' => 'por',
+        'ps' => 'pus',
         'qu' => 'que',
         'rm' => 'roh',
         'ro' => 'ron',
@@ -778,7 +776,6 @@ class LanguagesTest extends ResourceBundleTestCase
         'ru' => 'rus',
         'sg' => 'sag',
         'sa' => 'san',
-        'sr' => 'srp',
         'si' => 'sin',
         'sk' => 'slk',
         'sl' => 'slv',
@@ -789,7 +786,9 @@ class LanguagesTest extends ResourceBundleTestCase
         'so' => 'som',
         'st' => 'sot',
         'es' => 'spa',
+        'sq' => 'sqi',
         'sc' => 'srd',
+        'sr' => 'srp',
         'ss' => 'ssw',
         'su' => 'sun',
         'sw' => 'swa',
@@ -819,6 +818,7 @@ class LanguagesTest extends ResourceBundleTestCase
         'yi' => 'yid',
         'yo' => 'yor',
         'za' => 'zha',
+        'zh' => 'zho',
         'zu' => 'zul',
     ];
 
diff --git a/src/Symfony/Component/Intl/Tests/NumberFormatter/AbstractNumberFormatterTest.php b/src/Symfony/Component/Intl/Tests/NumberFormatter/AbstractNumberFormatterTest.php
index 0d382341f5..464a0aac0c 100644
--- a/src/Symfony/Component/Intl/Tests/NumberFormatter/AbstractNumberFormatterTest.php
+++ b/src/Symfony/Component/Intl/Tests/NumberFormatter/AbstractNumberFormatterTest.php
@@ -11,6 +11,7 @@
 
 namespace Symfony\Component\Intl\Tests\NumberFormatter;
 
+use PHPUnit\Framework\Error\Warning;
 use PHPUnit\Framework\TestCase;
 use Symfony\Component\Intl\Globals\IntlGlobals;
 use Symfony\Component\Intl\NumberFormatter\NumberFormatter;
@@ -323,13 +324,7 @@ abstract class AbstractNumberFormatterTest extends TestCase
      */
     public function testFormatTypeCurrency($formatter, $value)
     {
-        $exceptionCode = 'PHPUnit\Framework\Error\Warning';
-
-        if (class_exists('PHPUnit_Framework_Error_Warning')) {
-            $exceptionCode = 'PHPUnit_Framework_Error_Warning';
-        }
-
-        $this->expectException($exceptionCode);
+        $this->expectException(Warning::class);
 
         $formatter->format($value, NumberFormatter::TYPE_CURRENCY);
     }
@@ -706,13 +701,7 @@ abstract class AbstractNumberFormatterTest extends TestCase
 
     public function testParseTypeDefault()
     {
-        $exceptionCode = 'PHPUnit\Framework\Error\Warning';
-
-        if (class_exists('PHPUnit_Framework_Error_Warning')) {
-            $exceptionCode = 'PHPUnit_Framework_Error_Warning';
-        }
-
-        $this->expectException($exceptionCode);
+        $this->expectException(Warning::class);
 
         $formatter = $this->getNumberFormatter('en', NumberFormatter::DECIMAL);
         $formatter->parse('1', NumberFormatter::TYPE_DEFAULT);
@@ -832,13 +821,7 @@ abstract class AbstractNumberFormatterTest extends TestCase
 
     public function testParseTypeCurrency()
     {
-        $exceptionCode = 'PHPUnit\Framework\Error\Warning';
-
-        if (class_exists('PHPUnit_Framework_Error_Warning')) {
-            $exceptionCode = 'PHPUnit_Framework_Error_Warning';
-        }
-
-        $this->expectException($exceptionCode);
+        $this->expectException(Warning::class);
 
         $formatter = $this->getNumberFormatter('en', NumberFormatter::DECIMAL);
         $formatter->parse('1', NumberFormatter::TYPE_CURRENCY);
diff --git a/src/Symfony/Component/Intl/Tests/Util/GitRepositoryTest.php b/src/Symfony/Component/Intl/Tests/Util/GitRepositoryTest.php
index 0932d60433..0d98392ac2 100644
--- a/src/Symfony/Component/Intl/Tests/Util/GitRepositoryTest.php
+++ b/src/Symfony/Component/Intl/Tests/Util/GitRepositoryTest.php
@@ -51,7 +51,7 @@ class GitRepositoryTest extends TestCase
         $git = GitRepository::download(self::REPO_URL, $this->targetDir);
 
         $this->assertInstanceOf(GitRepository::class, $git);
-        $this->assertTrue(is_dir($this->targetDir.'/.git'));
+        $this->assertDirectoryExists($this->targetDir.'/.git');
         $this->assertSame($this->targetDir, $git->getPath());
         $this->assertSame(self::REPO_URL, $git->getUrl());
         $this->assertRegExp('#^[0-9a-z]{40}$#', $git->getLastCommitHash());
diff --git a/src/Symfony/Component/Ldap/Security/LdapUserProvider.php b/src/Symfony/Component/Ldap/Security/LdapUserProvider.php
index 4e346cceef..0bc8bbe137 100644
--- a/src/Symfony/Component/Ldap/Security/LdapUserProvider.php
+++ b/src/Symfony/Component/Ldap/Security/LdapUserProvider.php
@@ -13,10 +13,12 @@ namespace Symfony\Component\Ldap\Security;
 
 use Symfony\Component\Ldap\Entry;
 use Symfony\Component\Ldap\Exception\ConnectionException;
+use Symfony\Component\Ldap\Exception\ExceptionInterface;
 use Symfony\Component\Ldap\LdapInterface;
 use Symfony\Component\Security\Core\Exception\InvalidArgumentException;
 use Symfony\Component\Security\Core\Exception\UnsupportedUserException;
 use Symfony\Component\Security\Core\Exception\UsernameNotFoundException;
+use Symfony\Component\Security\Core\User\PasswordUpgraderInterface;
 use Symfony\Component\Security\Core\User\UserInterface;
 use Symfony\Component\Security\Core\User\UserProviderInterface;
 
@@ -27,7 +29,7 @@ use Symfony\Component\Security\Core\User\UserProviderInterface;
  * @author Charles Sarrazin <charles@sarraz.in>
  * @author Robin Chalas <robin.chalas@gmail.com>
  */
-class LdapUserProvider implements UserProviderInterface
+class LdapUserProvider implements UserProviderInterface, PasswordUpgraderInterface
 {
     private $ldap;
     private $baseDn;
@@ -109,6 +111,30 @@ class LdapUserProvider implements UserProviderInterface
         return new LdapUser($user->getEntry(), $user->getUsername(), $user->getPassword(), $user->getRoles());
     }
 
+    /**
+     * {@inheritdoc}
+     */
+    public function upgradePassword(UserInterface $user, string $newEncodedPassword): void
+    {
+        if (!$user instanceof LdapUser) {
+            throw new UnsupportedUserException(sprintf('Instances of "%s" are not supported.', \get_class($user)));
+        }
+
+        if (null === $this->passwordAttribute) {
+            return;
+        }
+
+        try {
+            if ($user->isEqualTo($this->loadUserByUsername($user->getUsername()))) {
+                $user->getEntry()->setAttribute($this->passwordAttribute, [$newEncodedPassword]);
+                $this->ldap->getEntryManager()->update($user->getEntry());
+                $user->setPassword($newEncodedPassword);
+            }
+        } catch (ExceptionInterface $e) {
+            // ignore failed password upgrades
+        }
+    }
+
     /**
      * {@inheritdoc}
      */
diff --git a/src/Symfony/Component/Ldap/Tests/Security/User/LdapUserProviderTest.php b/src/Symfony/Component/Ldap/Tests/Security/User/LdapUserProviderTest.php
index 75839db4d3..eda39c43aa 100644
--- a/src/Symfony/Component/Ldap/Tests/Security/User/LdapUserProviderTest.php
+++ b/src/Symfony/Component/Ldap/Tests/Security/User/LdapUserProviderTest.php
@@ -26,11 +26,10 @@ use Symfony\Component\Ldap\Security\LdapUserProvider;
  */
 class LdapUserProviderTest extends TestCase
 {
-    /**
-     * @expectedException \Symfony\Component\Security\Core\Exception\UsernameNotFoundException
-     */
     public function testLoadUserByUsernameFailsIfCantConnectToLdap()
     {
+        $this->expectException(\Symfony\Component\Security\Core\Exception\UsernameNotFoundException::class);
+
         $ldap = $this->createMock(LdapInterface::class);
         $ldap
             ->expects($this->once())
@@ -42,11 +41,10 @@ class LdapUserProviderTest extends TestCase
         $provider->loadUserByUsername('foo');
     }
 
-    /**
-     * @expectedException \Symfony\Component\Security\Core\Exception\UsernameNotFoundException
-     */
     public function testLoadUserByUsernameFailsIfNoLdapEntries()
     {
+        $this->expectException(\Symfony\Component\Security\Core\Exception\UsernameNotFoundException::class);
+
         $result = $this->createMock(CollectionInterface::class);
         $query = $this->createMock(QueryInterface::class);
         $query
@@ -75,11 +73,10 @@ class LdapUserProviderTest extends TestCase
         $provider->loadUserByUsername('foo');
     }
 
-    /**
-     * @expectedException \Symfony\Component\Security\Core\Exception\UsernameNotFoundException
-     */
     public function testLoadUserByUsernameFailsIfMoreThanOneLdapEntry()
     {
+        $this->expectException(\Symfony\Component\Security\Core\Exception\UsernameNotFoundException::class);
+
         $result = $this->createMock(CollectionInterface::class);
         $query = $this->createMock(QueryInterface::class);
         $query
@@ -108,11 +105,10 @@ class LdapUserProviderTest extends TestCase
         $provider->loadUserByUsername('foo');
     }
 
-    /**
-     * @expectedException \Symfony\Component\Security\Core\Exception\InvalidArgumentException
-     */
     public function testLoadUserByUsernameFailsIfMoreThanOneLdapPasswordsInEntry()
     {
+        $this->expectException(\Symfony\Component\Security\Core\Exception\InvalidArgumentException::class);
+
         $result = $this->createMock(CollectionInterface::class);
         $query = $this->createMock(QueryInterface::class);
         $query
@@ -186,11 +182,10 @@ class LdapUserProviderTest extends TestCase
         $this->assertInstanceOf(LdapUser::class, $provider->loadUserByUsername('foo'));
     }
 
-    /**
-     * @expectedException \Symfony\Component\Security\Core\Exception\InvalidArgumentException
-     */
     public function testLoadUserByUsernameFailsIfEntryHasNoPasswordAttribute()
     {
+        $this->expectException(\Symfony\Component\Security\Core\Exception\InvalidArgumentException::class);
+
         $result = $this->createMock(CollectionInterface::class);
         $query = $this->createMock(QueryInterface::class);
         $query
diff --git a/src/Symfony/Component/Lock/Tests/LockTest.php b/src/Symfony/Component/Lock/Tests/LockTest.php
index 6b2baddb68..aae7a7671d 100644
--- a/src/Symfony/Component/Lock/Tests/LockTest.php
+++ b/src/Symfony/Component/Lock/Tests/LockTest.php
@@ -18,6 +18,7 @@ use Symfony\Component\Lock\Exception\LockConflictedException;
 use Symfony\Component\Lock\Key;
 use Symfony\Component\Lock\Lock;
 use Symfony\Component\Lock\PersistingStoreInterface;
+use Symfony\Component\Lock\StoreInterface;
 
 /**
  * @author Jérémy Derussé <jeremy@derusse.com>
@@ -56,7 +57,7 @@ class LockTest extends TestCase
     public function testPassingOldStoreInterface()
     {
         $key = new Key(uniqid(__METHOD__, true));
-        $store = $this->getMockBuilder(PersistingStoreInterface::class)->getMock();
+        $store = $this->getMockBuilder(StoreInterface::class)->getMock();
         $lock = new Lock($key, $store);
 
         $store
diff --git a/src/Symfony/Component/Mailer/Mailer.php b/src/Symfony/Component/Mailer/Mailer.php
index db87602022..8ac505b03d 100644
--- a/src/Symfony/Component/Mailer/Mailer.php
+++ b/src/Symfony/Component/Mailer/Mailer.php
@@ -17,6 +17,7 @@ use Symfony\Component\Mailer\Messenger\SendEmailMessage;
 use Symfony\Component\Mailer\Transport\TransportInterface;
 use Symfony\Component\Messenger\MessageBusInterface;
 use Symfony\Component\Mime\RawMessage;
+use Symfony\Contracts\EventDispatcher\EventDispatcherInterface;
 
 /**
  * @author Fabien Potencier <fabien@symfony.com>
@@ -25,8 +26,9 @@ class Mailer implements MailerInterface
 {
     private $transport;
     private $bus;
+    private $dispatcher;
 
-    public function __construct(TransportInterface $transport, MessageBusInterface $bus = null)
+    public function __construct(TransportInterface $transport, MessageBusInterface $bus = null, EventDispatcherInterface $dispatcher = null)
     {
         $this->transport = $transport;
         $this->bus = $bus;
@@ -40,18 +42,20 @@ class Mailer implements MailerInterface
             return;
         }
 
-        $message = clone $message;
-        if (null !== $envelope) {
-            $envelope = clone $envelope;
-        } else {
-            try {
-                $envelope = new DelayedSmtpEnvelope($message);
-            } catch (\Exception $e) {
-                throw new TransportException('Cannot send message without a valid envelope.', 0, $e);
+        if (null !== $this->dispatcher) {
+            $message = clone $message;
+            if (null !== $envelope) {
+                $envelope = clone $envelope;
+            } else {
+                try {
+                    $envelope = new DelayedSmtpEnvelope($message);
+                } catch (\Exception $e) {
+                    throw new TransportException('Cannot send message without a valid envelope.', 0, $e);
+                }
             }
+            $event = new MessageEvent($message, $envelope, $this->transport->getName());
+            $this->dispatcher->dispatch($event);
         }
-        $event = new MessageEvent($message, $envelope, $this->transport->getName());
-        $this->dispatcher->dispatch($event);
 
         $this->bus->dispatch(new SendEmailMessage($message, $envelope));
     }
diff --git a/src/Symfony/Component/Messenger/Command/ConsumeMessagesCommand.php b/src/Symfony/Component/Messenger/Command/ConsumeMessagesCommand.php
index d7fd8b121a..0832bce8ce 100644
--- a/src/Symfony/Component/Messenger/Command/ConsumeMessagesCommand.php
+++ b/src/Symfony/Component/Messenger/Command/ConsumeMessagesCommand.php
@@ -78,7 +78,7 @@ class ConsumeMessagesCommand extends Command
                 new InputOption('memory-limit', 'm', InputOption::VALUE_REQUIRED, 'The memory limit the worker can consume'),
                 new InputOption('time-limit', 't', InputOption::VALUE_REQUIRED, 'The time limit in seconds the worker can run'),
                 new InputOption('sleep', null, InputOption::VALUE_REQUIRED, 'Seconds to sleep before asking for new messages after no messages were found', 1),
-                new InputOption('bus', 'b', InputOption::VALUE_REQUIRED, 'Name of the bus to which received messages should be dispatched (if not passed, bus is determined automatically.'),
+                new InputOption('bus', 'b', InputOption::VALUE_REQUIRED, 'Name of the bus to which received messages should be dispatched (if not passed, bus is determined automatically)'),
             ])
             ->setDescription('Consumes messages')
             ->setHelp(<<<'EOF'
diff --git a/src/Symfony/Component/Security/CHANGELOG.md b/src/Symfony/Component/Security/CHANGELOG.md
index 618f51f8d2..d0ecbdb72d 100644
--- a/src/Symfony/Component/Security/CHANGELOG.md
+++ b/src/Symfony/Component/Security/CHANGELOG.md
@@ -36,6 +36,9 @@ CHANGELOG
  * Deprecated class `LdapUserProvider`, use `Symfony\Component\Ldap\Security\LdapUserProvider` instead
  * Added method `needsRehash()` to `PasswordEncoderInterface` and `UserPasswordEncoderInterface`
  * Added `MigratingPasswordEncoder`
+ * Added and implemented `PasswordUpgraderInterface`, for opportunistic password migrations
+ * Added `Guard\PasswordAuthenticatedInterface`, an optional interface
+   for "guard" authenticators that deal with user passwords
 
 4.3.0
 -----
diff --git a/src/Symfony/Component/Security/Core/Authentication/Provider/DaoAuthenticationProvider.php b/src/Symfony/Component/Security/Core/Authentication/Provider/DaoAuthenticationProvider.php
index f6fa66bc92..466c4f4536 100644
--- a/src/Symfony/Component/Security/Core/Authentication/Provider/DaoAuthenticationProvider.php
+++ b/src/Symfony/Component/Security/Core/Authentication/Provider/DaoAuthenticationProvider.php
@@ -16,6 +16,7 @@ use Symfony\Component\Security\Core\Encoder\EncoderFactoryInterface;
 use Symfony\Component\Security\Core\Exception\AuthenticationServiceException;
 use Symfony\Component\Security\Core\Exception\BadCredentialsException;
 use Symfony\Component\Security\Core\Exception\UsernameNotFoundException;
+use Symfony\Component\Security\Core\User\PasswordUpgraderInterface;
 use Symfony\Component\Security\Core\User\UserCheckerInterface;
 use Symfony\Component\Security\Core\User\UserInterface;
 use Symfony\Component\Security\Core\User\UserProviderInterface;
@@ -54,9 +55,15 @@ class DaoAuthenticationProvider extends UserAuthenticationProvider
                 throw new BadCredentialsException('The presented password cannot be empty.');
             }
 
-            if (!$this->encoderFactory->getEncoder($user)->isPasswordValid($user->getPassword(), $presentedPassword, $user->getSalt())) {
+            $encoder = $this->encoderFactory->getEncoder($user);
+
+            if (!$encoder->isPasswordValid($user->getPassword(), $presentedPassword, $user->getSalt())) {
                 throw new BadCredentialsException('The presented password is invalid.');
             }
+
+            if ($this->userProvider instanceof PasswordUpgraderInterface && method_exists($encoder, 'needsRehash') && $encoder->needsRehash($user->getPassword())) {
+                $this->userProvider->upgradePassword($user, $encoder->encodePassword($presentedPassword, $user->getSalt()));
+            }
         }
     }
 
diff --git a/src/Symfony/Component/Security/Core/Tests/Authentication/Provider/DaoAuthenticationProviderTest.php b/src/Symfony/Component/Security/Core/Tests/Authentication/Provider/DaoAuthenticationProviderTest.php
index 0907b9a32a..acee9a19e3 100644
--- a/src/Symfony/Component/Security/Core/Tests/Authentication/Provider/DaoAuthenticationProviderTest.php
+++ b/src/Symfony/Component/Security/Core/Tests/Authentication/Provider/DaoAuthenticationProviderTest.php
@@ -15,7 +15,11 @@ use PHPUnit\Framework\TestCase;
 use Symfony\Component\Security\Core\Authentication\Provider\DaoAuthenticationProvider;
 use Symfony\Component\Security\Core\Encoder\PlaintextPasswordEncoder;
 use Symfony\Component\Security\Core\Exception\UsernameNotFoundException;
+use Symfony\Component\Security\Core\Tests\Encoder\TestPasswordEncoderInterface;
+use Symfony\Component\Security\Core\User\PasswordUpgraderInterface;
+use Symfony\Component\Security\Core\User\User;
 use Symfony\Component\Security\Core\User\UserInterface;
+use Symfony\Component\Security\Core\User\UserProviderInterface;
 
 class DaoAuthenticationProviderTest extends TestCase
 {
@@ -240,6 +244,44 @@ class DaoAuthenticationProviderTest extends TestCase
         $method->invoke($provider, new TestUser(), $token);
     }
 
+    public function testPasswordUpgrades()
+    {
+        $user = new User('user', 'pwd');
+
+        $encoder = $this->getMockBuilder(TestPasswordEncoderInterface::class)->getMock();
+        $encoder->expects($this->once())
+                ->method('isPasswordValid')
+                ->willReturn(true)
+        ;
+        $encoder->expects($this->once())
+                ->method('encodePassword')
+                ->willReturn('foobar')
+        ;
+        $encoder->expects($this->once())
+                ->method('needsRehash')
+                ->willReturn(true)
+        ;
+
+        $provider = $this->getProvider(null, null, $encoder);
+
+        $userProvider = ((array) $provider)[sprintf("\0%s\0userProvider", DaoAuthenticationProvider::class)];
+        $userProvider->expects($this->once())
+            ->method('upgradePassword')
+            ->with($user, 'foobar')
+        ;
+
+        $method = new \ReflectionMethod($provider, 'checkAuthentication');
+        $method->setAccessible(true);
+
+        $token = $this->getSupportedToken();
+        $token->expects($this->once())
+              ->method('getCredentials')
+              ->willReturn('foo')
+        ;
+
+        $method->invoke($provider, $user, $token);
+    }
+
     protected function getSupportedToken()
     {
         $mock = $this->getMockBuilder('Symfony\\Component\\Security\\Core\\Authentication\\Token\\UsernamePasswordToken')->setMethods(['getCredentials', 'getUser', 'getProviderKey'])->disableOriginalConstructor()->getMock();
@@ -254,7 +296,7 @@ class DaoAuthenticationProviderTest extends TestCase
 
     protected function getProvider($user = null, $userChecker = null, $passwordEncoder = null)
     {
-        $userProvider = $this->getMockBuilder('Symfony\\Component\\Security\\Core\\User\\UserProviderInterface')->getMock();
+        $userProvider = $this->getMockBuilder([UserProviderInterface::class, PasswordUpgraderInterface::class])->getMock();
         if (null !== $user) {
             $userProvider->expects($this->once())
                          ->method('loadUserByUsername')
diff --git a/src/Symfony/Component/Security/Core/Tests/Encoder/MigratingPasswordEncoderTest.php b/src/Symfony/Component/Security/Core/Tests/Encoder/MigratingPasswordEncoderTest.php
index 245d6c182d..468c326f35 100644
--- a/src/Symfony/Component/Security/Core/Tests/Encoder/MigratingPasswordEncoderTest.php
+++ b/src/Symfony/Component/Security/Core/Tests/Encoder/MigratingPasswordEncoderTest.php
@@ -14,7 +14,6 @@ namespace Symfony\Component\Security\Core\Tests\Encoder;
 use PHPUnit\Framework\TestCase;
 use Symfony\Component\Security\Core\Encoder\MigratingPasswordEncoder;
 use Symfony\Component\Security\Core\Encoder\NativePasswordEncoder;
-use Symfony\Component\Security\Core\Encoder\PasswordEncoderInterface;
 
 class MigratingPasswordEncoderTest extends TestCase
 {
@@ -66,8 +65,3 @@ class MigratingPasswordEncoderTest extends TestCase
         $this->assertTrue($encoder->isPasswordValid('abc', 'foo', 'salt'));
     }
 }
-
-interface TestPasswordEncoderInterface extends PasswordEncoderInterface
-{
-    public function needsRehash(string $encoded): bool;
-}
diff --git a/src/Symfony/Component/Security/Core/Tests/Encoder/TestPasswordEncoderInterface.php b/src/Symfony/Component/Security/Core/Tests/Encoder/TestPasswordEncoderInterface.php
new file mode 100644
index 0000000000..13e2d0d3b3
--- /dev/null
+++ b/src/Symfony/Component/Security/Core/Tests/Encoder/TestPasswordEncoderInterface.php
@@ -0,0 +1,19 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Security\Core\Tests\Encoder;
+
+use Symfony\Component\Security\Core\Encoder\PasswordEncoderInterface;
+
+interface TestPasswordEncoderInterface extends PasswordEncoderInterface
+{
+    public function needsRehash(string $encoded): bool;
+}
diff --git a/src/Symfony/Component/Security/Core/Tests/User/ChainUserProviderTest.php b/src/Symfony/Component/Security/Core/Tests/User/ChainUserProviderTest.php
index 1592bcd2fe..aa9ade7020 100644
--- a/src/Symfony/Component/Security/Core/Tests/User/ChainUserProviderTest.php
+++ b/src/Symfony/Component/Security/Core/Tests/User/ChainUserProviderTest.php
@@ -15,6 +15,8 @@ use PHPUnit\Framework\TestCase;
 use Symfony\Component\Security\Core\Exception\UnsupportedUserException;
 use Symfony\Component\Security\Core\Exception\UsernameNotFoundException;
 use Symfony\Component\Security\Core\User\ChainUserProvider;
+use Symfony\Component\Security\Core\User\PasswordUpgraderInterface;
+use Symfony\Component\Security\Core\User\User;
 
 class ChainUserProviderTest extends TestCase
 {
@@ -188,6 +190,28 @@ class ChainUserProviderTest extends TestCase
         $this->assertSame($account, $provider->refreshUser($this->getAccount()));
     }
 
+    public function testPasswordUpgrades()
+    {
+        $user = new User('user', 'pwd');
+
+        $provider1 = $this->getMockBuilder(PasswordUpgraderInterface::class)->getMock();
+        $provider1
+            ->expects($this->once())
+            ->method('upgradePassword')
+            ->willThrowException(new UnsupportedUserException('unsupported'))
+        ;
+
+        $provider2 = $this->getMockBuilder(PasswordUpgraderInterface::class)->getMock();
+        $provider2
+            ->expects($this->once())
+            ->method('upgradePassword')
+            ->with($user, 'foobar')
+        ;
+
+        $provider = new ChainUserProvider([$provider1, $provider2]);
+        $provider->upgradePassword($user, 'foobar');
+    }
+
     protected function getAccount()
     {
         return $this->getMockBuilder('Symfony\Component\Security\Core\User\UserInterface')->getMock();
diff --git a/src/Symfony/Component/Security/Core/User/ChainUserProvider.php b/src/Symfony/Component/Security/Core/User/ChainUserProvider.php
index 9e9e86797b..68bb91ec47 100644
--- a/src/Symfony/Component/Security/Core/User/ChainUserProvider.php
+++ b/src/Symfony/Component/Security/Core/User/ChainUserProvider.php
@@ -22,7 +22,7 @@ use Symfony\Component\Security\Core\Exception\UsernameNotFoundException;
  *
  * @author Johannes M. Schmitt <schmittjoh@gmail.com>
  */
-class ChainUserProvider implements UserProviderInterface
+class ChainUserProvider implements UserProviderInterface, PasswordUpgraderInterface
 {
     private $providers;
 
@@ -104,4 +104,20 @@ class ChainUserProvider implements UserProviderInterface
 
         return false;
     }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function upgradePassword(UserInterface $user, string $newEncodedPassword): void
+    {
+        foreach ($this->providers as $provider) {
+            if ($provider instanceof PasswordUpgraderInterface) {
+                try {
+                    $provider->upgradePassword($user, $newEncodedPassword);
+                } catch (UnsupportedUserException $e) {
+                    // ignore: password upgrades are opportunistic
+                }
+            }
+        }
+    }
 }
diff --git a/src/Symfony/Component/Security/Core/User/PasswordUpgraderInterface.php b/src/Symfony/Component/Security/Core/User/PasswordUpgraderInterface.php
new file mode 100644
index 0000000000..9c65298b07
--- /dev/null
+++ b/src/Symfony/Component/Security/Core/User/PasswordUpgraderInterface.php
@@ -0,0 +1,27 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Security\Core\User;
+
+/**
+ * @author Nicolas Grekas <p@tchwork.com>
+ */
+interface PasswordUpgraderInterface
+{
+    /**
+     * Upgrades the encoded password of a user, typically for using a better hash algorithm.
+     *
+     * This method should persist the new password in the user storage and update the $user object accordingly.
+     * Because you don't want your users not being able to log in, this method should be opportunistic:
+     * it's fine if it does nothing or if it fails without throwing any exception.
+     */
+    public function upgradePassword(UserInterface $user, string $newEncodedPassword): void;
+}
diff --git a/src/Symfony/Component/Security/Guard/PasswordAuthenticatedInterface.php b/src/Symfony/Component/Security/Guard/PasswordAuthenticatedInterface.php
new file mode 100644
index 0000000000..4dd7a7b446
--- /dev/null
+++ b/src/Symfony/Component/Security/Guard/PasswordAuthenticatedInterface.php
@@ -0,0 +1,25 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Security\Guard;
+
+/**
+ * An optional interface for "guard" authenticators that deal with user passwords.
+ */
+interface PasswordAuthenticatedInterface
+{
+    /**
+     * Returns the clear-text password contained in credentials if any.
+     *
+     * @param mixed The user credentials
+     */
+    public function getPassword($credentials): ?string;
+}
diff --git a/src/Symfony/Component/Security/Guard/Provider/GuardAuthenticationProvider.php b/src/Symfony/Component/Security/Guard/Provider/GuardAuthenticationProvider.php
index ece66a8df0..ac295a6d08 100644
--- a/src/Symfony/Component/Security/Guard/Provider/GuardAuthenticationProvider.php
+++ b/src/Symfony/Component/Security/Guard/Provider/GuardAuthenticationProvider.php
@@ -13,14 +13,17 @@ namespace Symfony\Component\Security\Guard\Provider;
 
 use Symfony\Component\Security\Core\Authentication\Provider\AuthenticationProviderInterface;
 use Symfony\Component\Security\Core\Authentication\Token\TokenInterface;
+use Symfony\Component\Security\Core\Encoder\UserPasswordEncoderInterface;
 use Symfony\Component\Security\Core\Exception\AuthenticationException;
 use Symfony\Component\Security\Core\Exception\AuthenticationExpiredException;
 use Symfony\Component\Security\Core\Exception\BadCredentialsException;
 use Symfony\Component\Security\Core\Exception\UsernameNotFoundException;
+use Symfony\Component\Security\Core\User\PasswordUpgraderInterface;
 use Symfony\Component\Security\Core\User\UserCheckerInterface;
 use Symfony\Component\Security\Core\User\UserInterface;
 use Symfony\Component\Security\Core\User\UserProviderInterface;
 use Symfony\Component\Security\Guard\AuthenticatorInterface;
+use Symfony\Component\Security\Guard\PasswordAuthenticatedInterface;
 use Symfony\Component\Security\Guard\Token\GuardTokenInterface;
 use Symfony\Component\Security\Guard\Token\PreAuthenticationGuardToken;
 
@@ -39,19 +42,19 @@ class GuardAuthenticationProvider implements AuthenticationProviderInterface
     private $userProvider;
     private $providerKey;
     private $userChecker;
+    private $passwordEncoder;
 
     /**
      * @param iterable|AuthenticatorInterface[] $guardAuthenticators The authenticators, with keys that match what's passed to GuardAuthenticationListener
-     * @param UserProviderInterface             $userProvider        The user provider
      * @param string                            $providerKey         The provider (i.e. firewall) key
-     * @param UserCheckerInterface              $userChecker
      */
-    public function __construct($guardAuthenticators, UserProviderInterface $userProvider, string $providerKey, UserCheckerInterface $userChecker)
+    public function __construct($guardAuthenticators, UserProviderInterface $userProvider, string $providerKey, UserCheckerInterface $userChecker, UserPasswordEncoderInterface $passwordEncoder = null)
     {
         $this->guardAuthenticators = $guardAuthenticators;
         $this->userProvider = $userProvider;
         $this->providerKey = $providerKey;
         $this->userChecker = $userChecker;
+        $this->passwordEncoder = $passwordEncoder;
     }
 
     /**
@@ -113,6 +116,9 @@ class GuardAuthenticationProvider implements AuthenticationProviderInterface
         if (true !== $guardAuthenticator->checkCredentials($token->getCredentials(), $user)) {
             throw new BadCredentialsException(sprintf('Authentication failed because %s::checkCredentials() did not return true.', \get_class($guardAuthenticator)));
         }
+        if ($this->userProvider instanceof PasswordUpgraderInterface && $guardAuthenticator instanceof PasswordAuthenticatedInterface && null !== $this->passwordEncoder && (null !== $password = $guardAuthenticator->getPassword($token->getCredentials())) && method_exists($this->passwordEncoder, 'needsRehash') && $this->passwordEncoder->needsRehash($user)) {
+            $this->userProvider->upgradePassword($user, $this->passwordEncoder->encodePassword($user, $password));
+        }
         $this->userChecker->checkPostAuth($user);
 
         // turn the UserInterface into a TokenInterface
diff --git a/src/Symfony/Component/VarDumper/Cloner/AbstractCloner.php b/src/Symfony/Component/VarDumper/Cloner/AbstractCloner.php
index 21ccc471da..8e42337a75 100644
--- a/src/Symfony/Component/VarDumper/Cloner/AbstractCloner.php
+++ b/src/Symfony/Component/VarDumper/Cloner/AbstractCloner.php
@@ -91,6 +91,8 @@ abstract class AbstractCloner implements ClonerInterface
 
         'ProxyManager\Proxy\ProxyInterface' => ['Symfony\Component\VarDumper\Caster\ProxyManagerCaster', 'castProxy'],
         'PHPUnit_Framework_MockObject_MockObject' => ['Symfony\Component\VarDumper\Caster\StubCaster', 'cutInternals'],
+        'PHPUnit\Framework\MockObject\MockObject' => ['Symfony\Component\VarDumper\Caster\StubCaster', 'cutInternals'],
+        'PHPUnit\Framework\MockObject\Stub' => ['Symfony\Component\VarDumper\Caster\StubCaster', 'cutInternals'],
         'Prophecy\Prophecy\ProphecySubjectInterface' => ['Symfony\Component\VarDumper\Caster\StubCaster', 'cutInternals'],
         'Mockery\MockInterface' => ['Symfony\Component\VarDumper\Caster\StubCaster', 'cutInternals'],
 
diff --git a/src/Symfony/Component/Yaml/Inline.php b/src/Symfony/Component/Yaml/Inline.php
index 399759ae65..5e9e804ee8 100644
--- a/src/Symfony/Component/Yaml/Inline.php
+++ b/src/Symfony/Component/Yaml/Inline.php
@@ -33,7 +33,6 @@ class Inline
     private static $objectSupport = false;
     private static $objectForMap = false;
     private static $constantSupport = false;
-    private static $nullAsTilde = false;
 
     public static function initialize(int $flags, int $parsedLineNumber = null, string $parsedFilename = null)
     {
@@ -41,7 +40,6 @@ class Inline
         self::$objectSupport = (bool) (Yaml::PARSE_OBJECT & $flags);
         self::$objectForMap = (bool) (Yaml::PARSE_OBJECT_FOR_MAP & $flags);
         self::$constantSupport = (bool) (Yaml::PARSE_CONSTANT & $flags);
-        self::$nullAsTilde = (bool) (Yaml::DUMP_NULL_AS_TILDE & $flags);
         self::$parsedFilename = $parsedFilename;
 
         if (null !== $parsedLineNumber) {
diff --git a/src/Symfony/Contracts/HttpClient/Test/HttpClientTestCase.php b/src/Symfony/Contracts/HttpClient/Test/HttpClientTestCase.php
index 075f73a2c1..7d31a22217 100644
--- a/src/Symfony/Contracts/HttpClient/Test/HttpClientTestCase.php
+++ b/src/Symfony/Contracts/HttpClient/Test/HttpClientTestCase.php
@@ -580,7 +580,7 @@ abstract class HttpClientTestCase extends TestCase
 
         $response = null;
         $this->expectException(TransportExceptionInterface::class);
-        $client->request('GET', 'http://symfony.com:8057/', ['timeout' => 3]);
+        $client->request('GET', 'http://symfony.com:8057/', ['timeout' => 1]);
     }
 
     public function testTimeoutOnAccess()
@@ -643,7 +643,6 @@ abstract class HttpClientTestCase extends TestCase
     {
         $client = $this->getHttpClient(__FUNCTION__);
 
-        $downloaded = 0;
         $start = microtime(true);
         $client->request('GET', 'http://localhost:8057/timeout-long');
         $client = null;