Remove branch-version (keep them for contracts only)

Fix branch-version
Remove "version" from composer.json files, use "branch-version" instead
2026-03-24 17:22:11 +01:00 · 2020-10-24 12:57:07 +02:00 · 2020-10-13 15:20:16 +02:00 · 2020-10-13 14:21:16 +02:00 · 2020-10-06 17:25:25 +02:00 · 2020-10-06 13:22:52 +02:00
18 changed files with 406 additions and 351 deletions
--- a/ApcClassLoader.php
+++ b/ApcClassLoader.php
@@ -11,6 +11,8 @@

 namespace Symfony\Component\ClassLoader;

+@trigger_error('The '.__NAMESPACE__.'\ApcClassLoader class is deprecated since Symfony 3.3 and will be removed in 4.0. Use `composer install --apcu-autoloader` instead.', \E_USER_DEPRECATED);
+
 /**
 * ApcClassLoader implements a wrapping autoloader cached in APC for PHP 5.3.
 *
@@ -44,6 +46,8 @@ namespace Symfony\Component\ClassLoader;
 *
 * @author Fabien Potencier <fabien@symfony.com>
 * @author Kris Wallsmith <kris@symfony.com>
+ *
+ * @deprecated since version 3.3, to be removed in 4.0. Use `composer install --apcu-autoloader` instead.
 */
 class ApcClassLoader
 {
@@ -57,8 +61,6 @@ class ApcClassLoader
    protected $decorated;

    /**
-     * Constructor.
-     *
     * @param string $prefix    The APC namespace prefix to use
     * @param object $decorated A class loader object that implements the findFile() method
     *
@@ -67,7 +69,7 @@ class ApcClassLoader
     */
    public function __construct($prefix, $decorated)
    {
-        if (!function_exists('apcu_fetch')) {
+        if (!\function_exists('apcu_fetch')) {
            throw new \RuntimeException('Unable to use ApcClassLoader as APC is not installed.');
        }

@@ -86,7 +88,7 @@ class ApcClassLoader
     */
    public function register($prepend = false)
    {
-        spl_autoload_register(array($this, 'loadClass'), true, $prepend);
+        spl_autoload_register([$this, 'loadClass'], true, $prepend);
    }

    /**
@@ -94,7 +96,7 @@ class ApcClassLoader
     */
    public function unregister()
    {
-        spl_autoload_unregister(array($this, 'loadClass'));
+        spl_autoload_unregister([$this, 'loadClass']);
    }

    /**
@@ -111,6 +113,8 @@ class ApcClassLoader

            return true;
        }
+
+        return null;
    }

    /**
@@ -136,6 +140,6 @@ class ApcClassLoader
     */
    public function __call($method, $args)
    {
-        return call_user_func_array(array($this->decorated, $method), $args);
+        return \call_user_func_array([$this->decorated, $method], $args);
    }
 }
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,11 @@
 CHANGELOG
 =========

+3.3.0
+-----
+
+ * deprecated the component: use Composer instead
+
 3.0.0
 -----

--- a/ClassCollectionLoader.php
+++ b/ClassCollectionLoader.php
@@ -11,10 +11,16 @@

 namespace Symfony\Component\ClassLoader;

+if (\PHP_VERSION_ID >= 70000) {
+    @trigger_error('The '.__NAMESPACE__.'\ClassCollectionLoader class is deprecated since Symfony 3.3 and will be removed in 4.0.', \E_USER_DEPRECATED);
+}
+
 /**
 * ClassCollectionLoader.
 *
 * @author Fabien Potencier <fabien@symfony.com>
+ *
+ * @deprecated since version 3.3, to be removed in 4.0.
 */
 class ClassCollectionLoader
 {
@@ -50,16 +56,16 @@ class ClassCollectionLoader
            $classes = array_diff($classes, $declared);

            // the cache is different depending on which classes are already declared
-            $name = $name.'-'.substr(hash('sha256', implode('|', $classes)), 0, 5);
+            $name .= '-'.substr(hash('sha256', implode('|', $classes)), 0, 5);
        }

        $classes = array_unique($classes);

        // cache the core classes
        if (!is_dir($cacheDir) && !@mkdir($cacheDir, 0777, true) && !is_dir($cacheDir)) {
-            throw new \RuntimeException(sprintf('Class Collection Loader was not able to create directory "%s"', $cacheDir));
+            throw new \RuntimeException(sprintf('Class Collection Loader was not able to create directory "%s".', $cacheDir));
        }
-        $cacheDir = rtrim(realpath($cacheDir) ?: $cacheDir, '/'.DIRECTORY_SEPARATOR);
+        $cacheDir = rtrim(realpath($cacheDir) ?: $cacheDir, '/'.\DIRECTORY_SEPARATOR);
        $cache = $cacheDir.'/'.$name.$extension;

        // auto-reload
@@ -102,7 +108,7 @@ class ClassCollectionLoader

        if ($autoReload) {
            // save the resources
-            self::writeCacheFile($metadata, serialize(array(array_values($files), $classes)));
+            self::writeCacheFile($metadata, serialize([array_values($files), $classes]));
        }
    }

@@ -119,15 +125,15 @@ class ClassCollectionLoader
     */
    public static function inline($classes, $cache, array $excluded)
    {
-        $declared = array();
+        $declared = [];
        foreach (self::getOrderedClasses($excluded) as $class) {
            $declared[$class->getName()] = true;
        }

        // cache the core classes
-        $cacheDir = dirname($cache);
+        $cacheDir = \dirname($cache);
        if (!is_dir($cacheDir) && !@mkdir($cacheDir, 0777, true) && !is_dir($cacheDir)) {
-            throw new \RuntimeException(sprintf('Class Collection Loader was not able to create directory "%s"', $cacheDir));
+            throw new \RuntimeException(sprintf('Class Collection Loader was not able to create directory "%s".', $cacheDir));
        }

        $spacesRegex = '(?:\s*+(?:(?:\#|//)[^\n]*+\n|/\*(?:(?<!\*/).)++)?+)*+';
@@ -140,8 +146,8 @@ class ClassCollectionLoader
 REGEX;
        $dontInlineRegex = str_replace('.', $spacesRegex, $dontInlineRegex);

-        $cacheDir = explode('/', str_replace(DIRECTORY_SEPARATOR, '/', $cacheDir));
-        $files = array();
+        $cacheDir = explode('/', str_replace(\DIRECTORY_SEPARATOR, '/', $cacheDir));
+        $files = [];
        $content = '';
        foreach (self::getOrderedClasses($classes) as $class) {
            if (isset($declared[$class->getName()])) {
@@ -153,7 +159,7 @@ REGEX;
            $c = file_get_contents($file);

            if (preg_match($dontInlineRegex, $c)) {
-                $file = explode('/', str_replace(DIRECTORY_SEPARATOR, '/', $file));
+                $file = explode('/', str_replace(\DIRECTORY_SEPARATOR, '/', $file));

                for ($i = 0; isset($file[$i], $cacheDir[$i]); ++$i) {
                    if ($file[$i] !== $cacheDir[$i]) {
@@ -163,14 +169,14 @@ REGEX;
                if (1 >= $i) {
                    $file = var_export(implode('/', $file), true);
                } else {
-                    $file = array_slice($file, $i);
-                    $file = str_repeat('../', count($cacheDir) - $i).implode('/', $file);
+                    $file = \array_slice($file, $i);
+                    $file = str_repeat('../', \count($cacheDir) - $i).implode('/', $file);
                    $file = '__DIR__.'.var_export('/'.$file, true);
                }

                $c = "\nnamespace {require $file;}";
            } else {
-                $c = preg_replace(array('/^\s*<\?php/', '/\?>\s*$/'), '', $c);
+                $c = preg_replace(['/^\s*<\?php/', '/\?>\s*$/'], '', $c);

                // fakes namespace declaration for global code
                if (!$class->inNamespace()) {
@@ -197,7 +203,7 @@ REGEX;
     */
    public static function fixNamespaceDeclarations($source)
    {
-        if (!function_exists('token_get_all') || !self::$useTokenizer) {
+        if (!\function_exists('token_get_all') || !self::$useTokenizer) {
            if (preg_match('/(^|\s)namespace(.*?)\s*;/', $source)) {
                $source = preg_replace('/(^|\s)namespace(.*?)\s*;/', "$1namespace$2\n{", $source)."}\n";
            }
@@ -210,21 +216,26 @@ REGEX;
        $inNamespace = false;
        $tokens = token_get_all($source);

+        $nsTokens = [\T_WHITESPACE => true, \T_NS_SEPARATOR => true, \T_STRING => true];
+        if (\defined('T_NAME_QUALIFIED')) {
+            $nsTokens[T_NAME_QUALIFIED] = true;
+        }
+
        for ($i = 0; isset($tokens[$i]); ++$i) {
            $token = $tokens[$i];
            if (!isset($token[1]) || 'b"' === $token) {
                $rawChunk .= $token;
-            } elseif (in_array($token[0], array(T_COMMENT, T_DOC_COMMENT))) {
+            } elseif (\in_array($token[0], [\T_COMMENT, \T_DOC_COMMENT])) {
                // strip comments
                continue;
-            } elseif (T_NAMESPACE === $token[0]) {
+            } elseif (\T_NAMESPACE === $token[0]) {
                if ($inNamespace) {
                    $rawChunk .= "}\n";
                }
                $rawChunk .= $token[1];

                // namespace name and whitespaces
-                while (isset($tokens[++$i][1]) && in_array($tokens[$i][0], array(T_WHITESPACE, T_NS_SEPARATOR, T_STRING))) {
+                while (isset($tokens[++$i][1], $nsTokens[$tokens[$i][0]])) {
                    $rawChunk .= $tokens[$i][1];
                }
                if ('{' === $tokens[$i]) {
@@ -234,15 +245,15 @@ REGEX;
                    $rawChunk = rtrim($rawChunk)."\n{";
                    $inNamespace = true;
                }
-            } elseif (T_START_HEREDOC === $token[0]) {
+            } elseif (\T_START_HEREDOC === $token[0]) {
                $output .= self::compressCode($rawChunk).$token[1];
                do {
                    $token = $tokens[++$i];
                    $output .= isset($token[1]) && 'b"' !== $token ? $token[1] : $token;
-                } while ($token[0] !== T_END_HEREDOC);
+                } while (\T_END_HEREDOC !== $token[0]);
                $output .= "\n";
                $rawChunk = '';
-            } elseif (T_CONSTANT_ENCAPSED_STRING === $token[0]) {
+            } elseif (\T_CONSTANT_ENCAPSED_STRING === $token[0]) {
                $output .= self::compressCode($rawChunk).$token[1];
                $rawChunk = '';
            } else {
@@ -256,7 +267,7 @@ REGEX;

        $output .= self::compressCode($rawChunk);

-        if (PHP_VERSION_ID >= 70000) {
+        if (\PHP_VERSION_ID >= 70000) {
            // PHP 7 memory manager will not release after token_get_all(), see https://bugs.php.net/70098
            unset($tokens, $rawChunk);
            gc_mem_caches();
@@ -283,8 +294,8 @@ REGEX;
    private static function compressCode($code)
    {
        return preg_replace(
-            array('/^\s+/m', '/\s+$/m', '/([\n\r]+ *[\n\r]+)+/', '/[ \t]+/'),
-            array('', '', "\n", ' '),
+            ['/^\s+/m', '/\s+$/m', '/([\n\r]+ *[\n\r]+)+/', '/[ \t]+/'],
+            ['', '', "\n", ' '],
            $code
        );
    }
@@ -299,7 +310,7 @@ REGEX;
     */
    private static function writeCacheFile($file, $content)
    {
-        $dir = dirname($file);
+        $dir = \dirname($file);
        if (!is_writable($dir)) {
            throw new \RuntimeException(sprintf('Cache directory "%s" is not writable.', $dir));
        }
@@ -318,21 +329,19 @@ REGEX;
    /**
     * Gets an ordered array of passed classes including all their dependencies.
     *
-     * @param array $classes
-     *
     * @return \ReflectionClass[] An array of sorted \ReflectionClass instances (dependencies added if needed)
     *
     * @throws \InvalidArgumentException When a class can't be loaded
     */
    private static function getOrderedClasses(array $classes)
    {
-        $map = array();
-        self::$seen = array();
+        $map = [];
+        self::$seen = [];
        foreach ($classes as $class) {
            try {
                $reflectionClass = new \ReflectionClass($class);
            } catch (\ReflectionException $e) {
-                throw new \InvalidArgumentException(sprintf('Unable to load class "%s"', $class));
+                throw new \InvalidArgumentException(sprintf('Unable to load class "%s".', $class));
            }

            $map = array_merge($map, self::getClassHierarchy($reflectionClass));
@@ -344,12 +353,12 @@ REGEX;
    private static function getClassHierarchy(\ReflectionClass $class)
    {
        if (isset(self::$seen[$class->getName()])) {
-            return array();
+            return [];
        }

        self::$seen[$class->getName()] = true;

-        $classes = array($class);
+        $classes = [$class];
        $parent = $class;
        while (($parent = $parent->getParentClass()) && $parent->isUserDefined() && !isset(self::$seen[$parent->getName()])) {
            self::$seen[$parent->getName()] = true;
@@ -357,7 +366,7 @@ REGEX;
            array_unshift($classes, $parent);
        }

-        $traits = array();
+        $traits = [];

        foreach ($classes as $c) {
            foreach (self::resolveDependencies(self::computeTraitDeps($c), $c) as $trait) {
@@ -372,7 +381,7 @@ REGEX;

    private static function getInterfaces(\ReflectionClass $class)
    {
-        $classes = array();
+        $classes = [];

        foreach ($class->getInterfaces() as $interface) {
            $classes = array_merge($classes, self::getInterfaces($interface));
@@ -390,7 +399,7 @@ REGEX;
    private static function computeTraitDeps(\ReflectionClass $class)
    {
        $traits = $class->getTraits();
-        $deps = array($class->getName() => $traits);
+        $deps = [$class->getName() => $traits];
        while ($trait = array_pop($traits)) {
            if ($trait->isUserDefined() && !isset(self::$seen[$trait->getName()])) {
                self::$seen[$trait->getName()] = true;
--- a/ClassLoader.php
+++ b/ClassLoader.php
@@ -11,6 +11,8 @@

 namespace Symfony\Component\ClassLoader;

+@trigger_error('The '.__NAMESPACE__.'\ClassLoader class is deprecated since Symfony 3.3 and will be removed in 4.0. Use Composer instead.', \E_USER_DEPRECATED);
+
 /**
 * ClassLoader implements an PSR-0 class loader.
 *
@@ -36,11 +38,13 @@ namespace Symfony\Component\ClassLoader;
 *
 * @author Fabien Potencier <fabien@symfony.com>
 * @author Jordi Boggiano <j.boggiano@seld.be>
+ *
+ * @deprecated since version 3.3, to be removed in 4.0.
 */
 class ClassLoader
 {
-    private $prefixes = array();
-    private $fallbackDirs = array();
+    private $prefixes = [];
+    private $fallbackDirs = [];
    private $useIncludePath = false;

    /**
@@ -91,12 +95,12 @@ class ClassLoader
            return;
        }
        if (isset($this->prefixes[$prefix])) {
-            if (is_array($paths)) {
+            if (\is_array($paths)) {
                $this->prefixes[$prefix] = array_unique(array_merge(
                    $this->prefixes[$prefix],
                    $paths
                ));
-            } elseif (!in_array($paths, $this->prefixes[$prefix])) {
+            } elseif (!\in_array($paths, $this->prefixes[$prefix])) {
                $this->prefixes[$prefix][] = $paths;
            }
        } else {
@@ -132,7 +136,7 @@ class ClassLoader
     */
    public function register($prepend = false)
    {
-        spl_autoload_register(array($this, 'loadClass'), true, $prepend);
+        spl_autoload_register([$this, 'loadClass'], true, $prepend);
    }

    /**
@@ -140,7 +144,7 @@ class ClassLoader
     */
    public function unregister()
    {
-        spl_autoload_unregister(array($this, 'loadClass'));
+        spl_autoload_unregister([$this, 'loadClass']);
    }

    /**
@@ -157,6 +161,8 @@ class ClassLoader

            return true;
        }
+
+        return null;
    }

    /**
@@ -170,7 +176,7 @@ class ClassLoader
    {
        if (false !== $pos = strrpos($class, '\\')) {
            // namespaced class name
-            $classPath = str_replace('\\', DIRECTORY_SEPARATOR, substr($class, 0, $pos)).DIRECTORY_SEPARATOR;
+            $classPath = str_replace('\\', \DIRECTORY_SEPARATOR, substr($class, 0, $pos)).\DIRECTORY_SEPARATOR;
            $className = substr($class, $pos + 1);
        } else {
            // PEAR-like class name
@@ -178,26 +184,28 @@ class ClassLoader
            $className = $class;
        }

-        $classPath .= str_replace('_', DIRECTORY_SEPARATOR, $className).'.php';
+        $classPath .= str_replace('_', \DIRECTORY_SEPARATOR, $className).'.php';

        foreach ($this->prefixes as $prefix => $dirs) {
            if ($class === strstr($class, $prefix)) {
                foreach ($dirs as $dir) {
-                    if (file_exists($dir.DIRECTORY_SEPARATOR.$classPath)) {
-                        return $dir.DIRECTORY_SEPARATOR.$classPath;
+                    if (file_exists($dir.\DIRECTORY_SEPARATOR.$classPath)) {
+                        return $dir.\DIRECTORY_SEPARATOR.$classPath;
                    }
                }
            }
        }

        foreach ($this->fallbackDirs as $dir) {
-            if (file_exists($dir.DIRECTORY_SEPARATOR.$classPath)) {
-                return $dir.DIRECTORY_SEPARATOR.$classPath;
+            if (file_exists($dir.\DIRECTORY_SEPARATOR.$classPath)) {
+                return $dir.\DIRECTORY_SEPARATOR.$classPath;
            }
        }

        if ($this->useIncludePath && $file = stream_resolve_include_path($classPath)) {
            return $file;
        }
+
+        return null;
    }
 }
--- a/ClassMapGenerator.php
+++ b/ClassMapGenerator.php
@@ -11,10 +11,14 @@

 namespace Symfony\Component\ClassLoader;

+@trigger_error('The '.__NAMESPACE__.'\ClassMapGenerator class is deprecated since Symfony 3.3 and will be removed in 4.0. Use Composer instead.', \E_USER_DEPRECATED);
+
 /**
 * ClassMapGenerator.
 *
 * @author Gyula Sallai <salla016@gmail.com>
+ *
+ * @deprecated since version 3.3, to be removed in 4.0.
 */
 class ClassMapGenerator
 {
@@ -27,7 +31,7 @@ class ClassMapGenerator
    public static function dump($dirs, $file)
    {
        $dirs = (array) $dirs;
-        $maps = array();
+        $maps = [];

        foreach ($dirs as $dir) {
            $maps = array_merge($maps, static::createMap($dir));
@@ -45,11 +49,11 @@ class ClassMapGenerator
     */
    public static function createMap($dir)
    {
-        if (is_string($dir)) {
+        if (\is_string($dir)) {
            $dir = new \RecursiveIteratorIterator(new \RecursiveDirectoryIterator($dir));
        }

-        $map = array();
+        $map = [];

        foreach ($dir as $file) {
            if (!$file->isFile()) {
@@ -58,13 +62,13 @@ class ClassMapGenerator

            $path = $file->getRealPath() ?: $file->getPathname();

-            if (pathinfo($path, PATHINFO_EXTENSION) !== 'php') {
+            if ('php' !== pathinfo($path, \PATHINFO_EXTENSION)) {
                continue;
            }

            $classes = self::findClasses($path);

-            if (PHP_VERSION_ID >= 70000) {
+            if (\PHP_VERSION_ID >= 70000) {
                // PHP 7 memory manager will not release after token_get_all(), see https://bugs.php.net/70098
                gc_mem_caches();
            }
@@ -89,7 +93,12 @@ class ClassMapGenerator
        $contents = file_get_contents($path);
        $tokens = token_get_all($contents);

-        $classes = array();
+        $nsTokens = [\T_STRING => true, \T_NS_SEPARATOR => true];
+        if (\defined('T_NAME_QUALIFIED')) {
+            $nsTokens[T_NAME_QUALIFIED] = true;
+        }
+
+        $classes = [];

        $namespace = '';
        for ($i = 0; isset($tokens[$i]); ++$i) {
@@ -102,19 +111,19 @@ class ClassMapGenerator
            $class = '';

            switch ($token[0]) {
-                case T_NAMESPACE:
+                case \T_NAMESPACE:
                    $namespace = '';
                    // If there is a namespace, extract it
                    while (isset($tokens[++$i][1])) {
-                        if (in_array($tokens[$i][0], array(T_STRING, T_NS_SEPARATOR))) {
+                        if (isset($nsTokens[$tokens[$i][0]])) {
                            $namespace .= $tokens[$i][1];
                        }
                    }
                    $namespace .= '\\';
                    break;
-                case T_CLASS:
-                case T_INTERFACE:
-                case T_TRAIT:
+                case \T_CLASS:
+                case \T_INTERFACE:
+                case \T_TRAIT:
                    // Skip usage of ::class constant
                    $isClassConstant = false;
                    for ($j = $i - 1; $j > 0; --$j) {
@@ -122,10 +131,10 @@ class ClassMapGenerator
                            break;
                        }

-                        if (T_DOUBLE_COLON === $tokens[$j][0]) {
+                        if (\T_DOUBLE_COLON === $tokens[$j][0]) {
                            $isClassConstant = true;
                            break;
-                        } elseif (!in_array($tokens[$j][0], array(T_WHITESPACE, T_DOC_COMMENT, T_COMMENT))) {
+                        } elseif (!\in_array($tokens[$j][0], [\T_WHITESPACE, \T_DOC_COMMENT, \T_COMMENT])) {
                            break;
                        }
                    }
@@ -137,9 +146,9 @@ class ClassMapGenerator
                    // Find the classname
                    while (isset($tokens[++$i][1])) {
                        $t = $tokens[$i];
-                        if (T_STRING === $t[0]) {
+                        if (\T_STRING === $t[0]) {
                            $class .= $t[1];
-                        } elseif ('' !== $class && T_WHITESPACE === $t[0]) {
+                        } elseif ('' !== $class && \T_WHITESPACE === $t[0]) {
                            break;
                        }
                    }
--- a/2
+++ b/2
@@ -1,4 +1,4 @@
-Copyright (c) 2004-2017 Fabien Potencier
+Copyright (c) 2004-2020 Fabien Potencier

 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
--- a/MapClassLoader.php
+++ b/MapClassLoader.php
@@ -11,18 +11,20 @@

 namespace Symfony\Component\ClassLoader;

+@trigger_error('The '.__NAMESPACE__.'\MapClassLoader class is deprecated since Symfony 3.3 and will be removed in 4.0. Use Composer instead.', \E_USER_DEPRECATED);
+
 /**
 * A class loader that uses a mapping file to look up paths.
 *
 * @author Fabien Potencier <fabien@symfony.com>
+ *
+ * @deprecated since version 3.3, to be removed in 4.0.
 */
 class MapClassLoader
 {
-    private $map = array();
+    private $map = [];

    /**
-     * Constructor.
-     *
     * @param array $map A map where keys are classes and values the absolute file path
     */
    public function __construct(array $map)
@@ -37,7 +39,7 @@ class MapClassLoader
     */
    public function register($prepend = false)
    {
-        spl_autoload_register(array($this, 'loadClass'), true, $prepend);
+        spl_autoload_register([$this, 'loadClass'], true, $prepend);
    }

    /**
@@ -61,8 +63,6 @@ class MapClassLoader
     */
    public function findFile($class)
    {
-        if (isset($this->map[$class])) {
-            return $this->map[$class];
-        }
+        return isset($this->map[$class]) ? $this->map[$class] : null;
    }
 }
--- a/Psr4ClassLoader.php
+++ b/Psr4ClassLoader.php
@@ -11,19 +11,20 @@

 namespace Symfony\Component\ClassLoader;

+@trigger_error('The '.__NAMESPACE__.'\Psr4ClassLoader class is deprecated since Symfony 3.3 and will be removed in 4.0. Use Composer instead.', \E_USER_DEPRECATED);
+
 /**
 * A PSR-4 compatible class loader.
 *
 * See http://www.php-fig.org/psr/psr-4/
 *
 * @author Alexander M. Turek <me@derrabus.de>
+ *
+ * @deprecated since version 3.3, to be removed in 4.0.
 */
 class Psr4ClassLoader
 {
-    /**
-     * @var array
-     */
-    private $prefixes = array();
+    private $prefixes = [];

    /**
     * @param string $prefix
@@ -32,8 +33,8 @@ class Psr4ClassLoader
    public function addPrefix($prefix, $baseDir)
    {
        $prefix = trim($prefix, '\\').'\\';
-        $baseDir = rtrim($baseDir, DIRECTORY_SEPARATOR).DIRECTORY_SEPARATOR;
-        $this->prefixes[] = array($prefix, $baseDir);
+        $baseDir = rtrim($baseDir, \DIRECTORY_SEPARATOR).\DIRECTORY_SEPARATOR;
+        $this->prefixes[] = [$prefix, $baseDir];
    }

    /**
@@ -47,13 +48,15 @@ class Psr4ClassLoader

        foreach ($this->prefixes as list($currentPrefix, $currentBaseDir)) {
            if (0 === strpos($class, $currentPrefix)) {
-                $classWithoutPrefix = substr($class, strlen($currentPrefix));
-                $file = $currentBaseDir.str_replace('\\', DIRECTORY_SEPARATOR, $classWithoutPrefix).'.php';
+                $classWithoutPrefix = substr($class, \strlen($currentPrefix));
+                $file = $currentBaseDir.str_replace('\\', \DIRECTORY_SEPARATOR, $classWithoutPrefix).'.php';
                if (file_exists($file)) {
                    return $file;
                }
            }
        }
+
+        return null;
    }

    /**
@@ -80,7 +83,7 @@ class Psr4ClassLoader
     */
    public function register($prepend = false)
    {
-        spl_autoload_register(array($this, 'loadClass'), true, $prepend);
+        spl_autoload_register([$this, 'loadClass'], true, $prepend);
    }

    /**
@@ -88,6 +91,6 @@ class Psr4ClassLoader
     */
    public function unregister()
    {
-        spl_autoload_unregister(array($this, 'loadClass'));
+        spl_autoload_unregister([$this, 'loadClass']);
    }
 }
--- a/README.md
+++ b/README.md
@@ -7,7 +7,7 @@ their locations for performance.
 Resources
 ---------

-  * [Documentation](https://symfony.com/doc/current/components/class_loader/index.html)
+  * [Documentation](https://symfony.com/doc/current/components/class_loader.html)
  * [Contributing](https://symfony.com/doc/current/contributing/index.html)
  * [Report issues](https://github.com/symfony/symfony/issues) and
    [send Pull Requests](https://github.com/symfony/symfony/pulls)
--- a/Tests/ApcClassLoaderTest.php
+++ b/Tests/ApcClassLoaderTest.php
@@ -11,14 +11,18 @@

 namespace Symfony\Component\ClassLoader\Tests;

+use PHPUnit\Framework\TestCase;
 use Symfony\Component\ClassLoader\ApcClassLoader;
 use Symfony\Component\ClassLoader\ClassLoader;

-class ApcClassLoaderTest extends \PHPUnit_Framework_TestCase
+/**
+ * @group legacy
+ */
+class ApcClassLoaderTest extends TestCase
 {
    protected function setUp()
    {
-        if (!(ini_get('apc.enabled') && ini_get('apc.enable_cli'))) {
+        if (!(filter_var(ini_get('apc.enabled'), \FILTER_VALIDATE_BOOLEAN) && filter_var(ini_get('apc.enable_cli'), \FILTER_VALIDATE_BOOLEAN))) {
            $this->markTestSkipped('The apc extension is not enabled.');
        } else {
            apcu_clear_cache();
@@ -27,7 +31,7 @@ class ApcClassLoaderTest extends \PHPUnit_Framework_TestCase

    protected function tearDown()
    {
-        if (ini_get('apc.enabled') && ini_get('apc.enable_cli')) {
+        if (filter_var(ini_get('apc.enabled'), \FILTER_VALIDATE_BOOLEAN) && filter_var(ini_get('apc.enable_cli'), \FILTER_VALIDATE_BOOLEAN)) {
            apcu_clear_cache();
        }
    }
@@ -35,7 +39,7 @@ class ApcClassLoaderTest extends \PHPUnit_Framework_TestCase
    public function testConstructor()
    {
        $loader = new ClassLoader();
-        $loader->addPrefix('Apc\Namespaced', __DIR__.DIRECTORY_SEPARATOR.'Fixtures');
+        $loader->addPrefix('Apc\Namespaced', __DIR__.\DIRECTORY_SEPARATOR.'Fixtures');

        $loader = new ApcClassLoader('test.prefix.', $loader);

@@ -48,8 +52,8 @@ class ApcClassLoaderTest extends \PHPUnit_Framework_TestCase
    public function testLoadClass($className, $testClassName, $message)
    {
        $loader = new ClassLoader();
-        $loader->addPrefix('Apc\Namespaced', __DIR__.DIRECTORY_SEPARATOR.'Fixtures');
-        $loader->addPrefix('Apc_Pearlike_', __DIR__.DIRECTORY_SEPARATOR.'Fixtures');
+        $loader->addPrefix('Apc\Namespaced', __DIR__.\DIRECTORY_SEPARATOR.'Fixtures');
+        $loader->addPrefix('Apc_Pearlike_', __DIR__.\DIRECTORY_SEPARATOR.'Fixtures');

        $loader = new ApcClassLoader('test.prefix.', $loader);
        $loader->loadClass($testClassName);
@@ -58,10 +62,10 @@ class ApcClassLoaderTest extends \PHPUnit_Framework_TestCase

    public function getLoadClassTests()
    {
-        return array(
-           array('\\Apc\\Namespaced\\Foo', 'Apc\\Namespaced\\Foo',   '->loadClass() loads Apc\Namespaced\Foo class'),
-           array('Apc_Pearlike_Foo',    'Apc_Pearlike_Foo',      '->loadClass() loads Apc_Pearlike_Foo class'),
-        );
+        return [
+           ['\\Apc\\Namespaced\\Foo', 'Apc\\Namespaced\\Foo',   '->loadClass() loads Apc\Namespaced\Foo class'],
+           ['Apc_Pearlike_Foo',    'Apc_Pearlike_Foo',      '->loadClass() loads Apc_Pearlike_Foo class'],
+        ];
    }

    /**
@@ -70,9 +74,9 @@ class ApcClassLoaderTest extends \PHPUnit_Framework_TestCase
    public function testLoadClassFromFallback($className, $testClassName, $message)
    {
        $loader = new ClassLoader();
-        $loader->addPrefix('Apc\Namespaced', __DIR__.DIRECTORY_SEPARATOR.'Fixtures');
-        $loader->addPrefix('Apc_Pearlike_', __DIR__.DIRECTORY_SEPARATOR.'Fixtures');
-        $loader->addPrefix('', array(__DIR__.DIRECTORY_SEPARATOR.'Fixtures/Apc/fallback'));
+        $loader->addPrefix('Apc\Namespaced', __DIR__.\DIRECTORY_SEPARATOR.'Fixtures');
+        $loader->addPrefix('Apc_Pearlike_', __DIR__.\DIRECTORY_SEPARATOR.'Fixtures');
+        $loader->addPrefix('', [__DIR__.\DIRECTORY_SEPARATOR.'Fixtures/Apc/fallback']);

        $loader = new ApcClassLoader('test.prefix.fallback', $loader);
        $loader->loadClass($testClassName);
@@ -82,12 +86,12 @@ class ApcClassLoaderTest extends \PHPUnit_Framework_TestCase

    public function getLoadClassFromFallbackTests()
    {
-        return array(
-           array('\\Apc\\Namespaced\\Baz',    'Apc\\Namespaced\\Baz',    '->loadClass() loads Apc\Namespaced\Baz class'),
-           array('Apc_Pearlike_Baz',       'Apc_Pearlike_Baz',       '->loadClass() loads Apc_Pearlike_Baz class'),
-           array('\\Apc\\Namespaced\\FooBar', 'Apc\\Namespaced\\FooBar', '->loadClass() loads Apc\Namespaced\Baz class from fallback dir'),
-           array('Apc_Pearlike_FooBar',    'Apc_Pearlike_FooBar',    '->loadClass() loads Apc_Pearlike_Baz class from fallback dir'),
-       );
+        return [
+           ['\\Apc\\Namespaced\\Baz',    'Apc\\Namespaced\\Baz',    '->loadClass() loads Apc\Namespaced\Baz class'],
+           ['Apc_Pearlike_Baz',       'Apc_Pearlike_Baz',       '->loadClass() loads Apc_Pearlike_Baz class'],
+           ['\\Apc\\Namespaced\\FooBar', 'Apc\\Namespaced\\FooBar', '->loadClass() loads Apc\Namespaced\Baz class from fallback dir'],
+           ['Apc_Pearlike_FooBar',    'Apc_Pearlike_FooBar',    '->loadClass() loads Apc_Pearlike_Baz class from fallback dir'],
+       ];
    }

    /**
@@ -106,40 +110,40 @@ class ApcClassLoaderTest extends \PHPUnit_Framework_TestCase

    public function getLoadClassNamespaceCollisionTests()
    {
-        return array(
-           array(
-               array(
-                   'Apc\\NamespaceCollision\\A' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/Apc/alpha',
-                   'Apc\\NamespaceCollision\\A\\B' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/Apc/beta',
-               ),
+        return [
+           [
+               [
+                   'Apc\\NamespaceCollision\\A' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/Apc/alpha',
+                   'Apc\\NamespaceCollision\\A\\B' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/Apc/beta',
+               ],
               'Apc\NamespaceCollision\A\Foo',
               '->loadClass() loads NamespaceCollision\A\Foo from alpha.',
-           ),
-           array(
-               array(
-                   'Apc\\NamespaceCollision\\A\\B' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/Apc/beta',
-                   'Apc\\NamespaceCollision\\A' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/Apc/alpha',
-               ),
+           ],
+           [
+               [
+                   'Apc\\NamespaceCollision\\A\\B' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/Apc/beta',
+                   'Apc\\NamespaceCollision\\A' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/Apc/alpha',
+               ],
               'Apc\NamespaceCollision\A\Bar',
               '->loadClass() loads NamespaceCollision\A\Bar from alpha.',
-           ),
-           array(
-               array(
-                   'Apc\\NamespaceCollision\\A' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/Apc/alpha',
-                   'Apc\\NamespaceCollision\\A\\B' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/Apc/beta',
-               ),
+           ],
+           [
+               [
+                   'Apc\\NamespaceCollision\\A' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/Apc/alpha',
+                   'Apc\\NamespaceCollision\\A\\B' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/Apc/beta',
+               ],
               'Apc\NamespaceCollision\A\B\Foo',
               '->loadClass() loads NamespaceCollision\A\B\Foo from beta.',
-           ),
-           array(
-               array(
-                   'Apc\\NamespaceCollision\\A\\B' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/Apc/beta',
-                   'Apc\\NamespaceCollision\\A' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/Apc/alpha',
-               ),
+           ],
+           [
+               [
+                   'Apc\\NamespaceCollision\\A\\B' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/Apc/beta',
+                   'Apc\\NamespaceCollision\\A' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/Apc/alpha',
+               ],
               'Apc\NamespaceCollision\A\B\Bar',
               '->loadClass() loads NamespaceCollision\A\B\Bar from beta.',
-           ),
-        );
+           ],
+        ];
    }

    /**
@@ -158,39 +162,39 @@ class ApcClassLoaderTest extends \PHPUnit_Framework_TestCase

    public function getLoadClassPrefixCollisionTests()
    {
-        return array(
-           array(
-               array(
-                   'ApcPrefixCollision_A_' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/Apc/alpha/Apc',
-                   'ApcPrefixCollision_A_B_' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/Apc/beta/Apc',
-               ),
+        return [
+           [
+               [
+                   'ApcPrefixCollision_A_' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/Apc/alpha/Apc',
+                   'ApcPrefixCollision_A_B_' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/Apc/beta/Apc',
+               ],
               'ApcPrefixCollision_A_Foo',
               '->loadClass() loads ApcPrefixCollision_A_Foo from alpha.',
-           ),
-           array(
-               array(
-                   'ApcPrefixCollision_A_B_' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/Apc/beta/Apc',
-                   'ApcPrefixCollision_A_' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/Apc/alpha/Apc',
-               ),
+           ],
+           [
+               [
+                   'ApcPrefixCollision_A_B_' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/Apc/beta/Apc',
+                   'ApcPrefixCollision_A_' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/Apc/alpha/Apc',
+               ],
               'ApcPrefixCollision_A_Bar',
               '->loadClass() loads ApcPrefixCollision_A_Bar from alpha.',
-           ),
-           array(
-               array(
-                   'ApcPrefixCollision_A_' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/Apc/alpha/Apc',
-                   'ApcPrefixCollision_A_B_' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/Apc/beta/Apc',
-               ),
+           ],
+           [
+               [
+                   'ApcPrefixCollision_A_' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/Apc/alpha/Apc',
+                   'ApcPrefixCollision_A_B_' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/Apc/beta/Apc',
+               ],
               'ApcPrefixCollision_A_B_Foo',
               '->loadClass() loads ApcPrefixCollision_A_B_Foo from beta.',
-           ),
-           array(
-               array(
-                   'ApcPrefixCollision_A_B_' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/Apc/beta/Apc',
-                   'ApcPrefixCollision_A_' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/Apc/alpha/Apc',
-               ),
+           ],
+           [
+               [
+                   'ApcPrefixCollision_A_B_' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/Apc/beta/Apc',
+                   'ApcPrefixCollision_A_' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/Apc/alpha/Apc',
+               ],
               'ApcPrefixCollision_A_B_Bar',
               '->loadClass() loads ApcPrefixCollision_A_B_Bar from beta.',
-           ),
-        );
+           ],
+        ];
    }
 }
--- a/Tests/ClassCollectionLoaderTest.php
+++ b/Tests/ClassCollectionLoaderTest.php
@@ -11,6 +11,7 @@

 namespace Symfony\Component\ClassLoader\Tests;

+use PHPUnit\Framework\TestCase;
 use Symfony\Component\ClassLoader\ClassCollectionLoader;
 use Symfony\Component\ClassLoader\Tests\Fixtures\DeclaredClass;
 use Symfony\Component\ClassLoader\Tests\Fixtures\WarmedClass;
@@ -20,7 +21,10 @@ require_once __DIR__.'/Fixtures/ClassesWithParents/CInterface.php';
 require_once __DIR__.'/Fixtures/ClassesWithParents/B.php';
 require_once __DIR__.'/Fixtures/ClassesWithParents/A.php';

-class ClassCollectionLoaderTest extends \PHPUnit_Framework_TestCase
+/**
+ * @group legacy
+ */
+class ClassCollectionLoaderTest extends TestCase
 {
    public function testTraitDependencies()
    {
@@ -30,17 +34,17 @@ class ClassCollectionLoaderTest extends \PHPUnit_Framework_TestCase
        $m = $r->getMethod('getOrderedClasses');
        $m->setAccessible(true);

-        $ordered = $m->invoke(null, array('CTFoo'));
+        $ordered = $m->invoke(null, ['CTFoo']);

        $this->assertEquals(
-            array('TD', 'TC', 'TB', 'TA', 'TZ', 'CTFoo'),
+            ['TD', 'TC', 'TB', 'TA', 'TZ', 'CTFoo'],
            array_map(function ($class) { return $class->getName(); }, $ordered)
        );

-        $ordered = $m->invoke(null, array('CTBar'));
+        $ordered = $m->invoke(null, ['CTBar']);

        $this->assertEquals(
-            array('TD', 'TZ', 'TC', 'TB', 'TA', 'CTBar'),
+            ['TD', 'TZ', 'TC', 'TB', 'TA', 'CTBar'],
            array_map(function ($class) { return $class->getName(); }, $ordered)
        );
    }
@@ -50,12 +54,12 @@ class ClassCollectionLoaderTest extends \PHPUnit_Framework_TestCase
     */
    public function testClassReordering(array $classes)
    {
-        $expected = array(
+        $expected = [
            'ClassesWithParents\\GInterface',
            'ClassesWithParents\\CInterface',
            'ClassesWithParents\\B',
            'ClassesWithParents\\A',
-        );
+        ];

        $r = new \ReflectionClass('Symfony\Component\ClassLoader\ClassCollectionLoader');
        $m = $r->getMethod('getOrderedClasses');
@@ -68,27 +72,27 @@ class ClassCollectionLoaderTest extends \PHPUnit_Framework_TestCase

    public function getDifferentOrders()
    {
-        return array(
-            array(array(
+        return [
+            [[
                'ClassesWithParents\\A',
                'ClassesWithParents\\CInterface',
                'ClassesWithParents\\GInterface',
                'ClassesWithParents\\B',
-            )),
-            array(array(
+            ]],
+            [[
                'ClassesWithParents\\B',
                'ClassesWithParents\\A',
                'ClassesWithParents\\CInterface',
-            )),
-            array(array(
+            ]],
+            [[
                'ClassesWithParents\\CInterface',
                'ClassesWithParents\\B',
                'ClassesWithParents\\A',
-            )),
-            array(array(
+            ]],
+            [[
                'ClassesWithParents\\A',
-            )),
-        );
+            ]],
+        ];
    }

    /**
@@ -102,7 +106,7 @@ class ClassCollectionLoaderTest extends \PHPUnit_Framework_TestCase
        require_once __DIR__.'/Fixtures/ClassesWithParents/D.php';
        require_once __DIR__.'/Fixtures/ClassesWithParents/E.php';

-        $expected = array(
+        $expected = [
            'ClassesWithParents\\GInterface',
            'ClassesWithParents\\CInterface',
            'ClassesWithParents\\ATrait',
@@ -112,7 +116,7 @@ class ClassCollectionLoaderTest extends \PHPUnit_Framework_TestCase
            'ClassesWithParents\\A',
            'ClassesWithParents\\D',
            'ClassesWithParents\\E',
-        );
+        ];

        $r = new \ReflectionClass('Symfony\Component\ClassLoader\ClassCollectionLoader');
        $m = $r->getMethod('getOrderedClasses');
@@ -125,15 +129,15 @@ class ClassCollectionLoaderTest extends \PHPUnit_Framework_TestCase

    public function getDifferentOrdersForTraits()
    {
-        return array(
-            array(array(
+        return [
+            [[
                'ClassesWithParents\\E',
                'ClassesWithParents\\ATrait',
-            )),
-            array(array(
+            ]],
+            [[
                'ClassesWithParents\\E',
-            )),
-        );
+            ]],
+        ];
    }

    public function testFixClassWithTraitsOrdering()
@@ -142,16 +146,16 @@ class ClassCollectionLoaderTest extends \PHPUnit_Framework_TestCase
        require_once __DIR__.'/Fixtures/ClassesWithParents/F.php';
        require_once __DIR__.'/Fixtures/ClassesWithParents/G.php';

-        $classes = array(
+        $classes = [
            'ClassesWithParents\\F',
            'ClassesWithParents\\G',
-        );
+        ];

-        $expected = array(
+        $expected = [
            'ClassesWithParents\\CTrait',
            'ClassesWithParents\\F',
            'ClassesWithParents\\G',
-        );
+        ];

        $r = new \ReflectionClass('Symfony\Component\ClassLoader\ClassCollectionLoader');
        $m = $r->getMethod('getOrderedClasses');
@@ -172,14 +176,14 @@ class ClassCollectionLoaderTest extends \PHPUnit_Framework_TestCase

    public function getFixNamespaceDeclarationsData()
    {
-        return array(
-            array("namespace;\nclass Foo {}\n", "namespace\n{\nclass Foo {}\n}"),
-            array("namespace Foo;\nclass Foo {}\n", "namespace Foo\n{\nclass Foo {}\n}"),
-            array("namespace   Bar ;\nclass Foo {}\n", "namespace Bar\n{\nclass Foo {}\n}"),
-            array("namespace Foo\Bar;\nclass Foo {}\n", "namespace Foo\Bar\n{\nclass Foo {}\n}"),
-            array("namespace Foo\Bar\Bar\n{\nclass Foo {}\n}\n", "namespace Foo\Bar\Bar\n{\nclass Foo {}\n}"),
-            array("namespace\n{\nclass Foo {}\n}\n", "namespace\n{\nclass Foo {}\n}"),
-        );
+        return [
+            ["namespace;\nclass Foo {}\n", "namespace\n{\nclass Foo {}\n}"],
+            ["namespace Foo;\nclass Foo {}\n", "namespace Foo\n{\nclass Foo {}\n}"],
+            ["namespace   Bar ;\nclass Foo {}\n", "namespace Bar\n{\nclass Foo {}\n}"],
+            ["namespace Foo\Bar;\nclass Foo {}\n", "namespace Foo\Bar\n{\nclass Foo {}\n}"],
+            ["namespace Foo\Bar\Bar\n{\nclass Foo {}\n}\n", "namespace Foo\Bar\Bar\n{\nclass Foo {}\n}"],
+            ["namespace\n{\nclass Foo {}\n}\n", "namespace\n{\nclass Foo {}\n}"],
+        ];
    }

    /**
@@ -194,26 +198,24 @@ class ClassCollectionLoaderTest extends \PHPUnit_Framework_TestCase

    public function getFixNamespaceDeclarationsDataWithoutTokenizer()
    {
-        return array(
-            array("namespace;\nclass Foo {}\n", "namespace\n{\nclass Foo {}\n}\n"),
-            array("namespace Foo;\nclass Foo {}\n", "namespace Foo\n{\nclass Foo {}\n}\n"),
-            array("namespace   Bar ;\nclass Foo {}\n", "namespace   Bar\n{\nclass Foo {}\n}\n"),
-            array("namespace Foo\Bar;\nclass Foo {}\n", "namespace Foo\Bar\n{\nclass Foo {}\n}\n"),
-            array("namespace Foo\Bar\Bar\n{\nclass Foo {}\n}\n", "namespace Foo\Bar\Bar\n{\nclass Foo {}\n}\n"),
-            array("\nnamespace\n{\nclass Foo {}\n\$namespace=123;}\n", "\nnamespace\n{\nclass Foo {}\n\$namespace=123;}\n"),
-        );
+        return [
+            ["namespace;\nclass Foo {}\n", "namespace\n{\nclass Foo {}\n}\n"],
+            ["namespace Foo;\nclass Foo {}\n", "namespace Foo\n{\nclass Foo {}\n}\n"],
+            ["namespace   Bar ;\nclass Foo {}\n", "namespace   Bar\n{\nclass Foo {}\n}\n"],
+            ["namespace Foo\Bar;\nclass Foo {}\n", "namespace Foo\Bar\n{\nclass Foo {}\n}\n"],
+            ["namespace Foo\Bar\Bar\n{\nclass Foo {}\n}\n", "namespace Foo\Bar\Bar\n{\nclass Foo {}\n}\n"],
+            ["\nnamespace\n{\nclass Foo {}\n\$namespace=123;}\n", "\nnamespace\n{\nclass Foo {}\n\$namespace=123;}\n"],
+        ];
    }

-    /**
-     * @expectedException \InvalidArgumentException
-     */
    public function testUnableToLoadClassException()
    {
+        $this->expectException('InvalidArgumentException');
        if (is_file($file = sys_get_temp_dir().'/foo.php')) {
            unlink($file);
        }

-        ClassCollectionLoader::load(array('SomeNotExistingClass'), sys_get_temp_dir(), 'foo', false);
+        ClassCollectionLoader::load(['SomeNotExistingClass'], sys_get_temp_dir(), 'foo', false);
    }

    public function testCommentStripping()
@@ -223,14 +225,14 @@ class ClassCollectionLoaderTest extends \PHPUnit_Framework_TestCase
        }
        spl_autoload_register($r = function ($class) {
            if (0 === strpos($class, 'Namespaced') || 0 === strpos($class, 'Pearlike_')) {
-                @require_once __DIR__.'/Fixtures/'.str_replace(array('\\', '_'), '/', $class).'.php';
+                @require_once __DIR__.'/Fixtures/'.str_replace(['\\', '_'], '/', $class).'.php';
            }
        });

-        $strictTypes = defined('HHVM_VERSION') ? '' : "\nnamespace {require __DIR__.'/Fixtures/Namespaced/WithStrictTypes.php';}";
+        $strictTypes = \defined('HHVM_VERSION') ? '' : "\nnamespace {require __DIR__.'/Fixtures/Namespaced/WithStrictTypes.php';}";

        ClassCollectionLoader::load(
-            array('Namespaced\\WithComments', 'Pearlike_WithComments', 'Namespaced\\WithDirMagic', 'Namespaced\\WithFileMagic', 'Namespaced\\WithHaltCompiler', $strictTypes ? 'Namespaced\\WithStrictTypes' : 'Namespaced\\WithComments'),
+            ['Namespaced\\WithComments', 'Pearlike_WithComments', 'Namespaced\\WithDirMagic', 'Namespaced\\WithFileMagic', 'Namespaced\\WithHaltCompiler', $strictTypes ? 'Namespaced\\WithStrictTypes' : 'Namespaced\\WithComments'],
            __DIR__,
            'bar',
            false
@@ -275,7 +277,7 @@ namespace {require __DIR__.'/Fixtures/Namespaced/WithFileMagic.php';}
 namespace {require __DIR__.'/Fixtures/Namespaced/WithHaltCompiler.php';}
 EOF
            .$strictTypes,
-            str_replace(array("<?php \n", '\\\\'), array('', '/'), file_get_contents($file))
+            str_replace(["<?php \n", '\\\\'], ['', '/'], file_get_contents($file))
        );

        unlink($file);
@@ -287,8 +289,8 @@ EOF

        @unlink($cache = sys_get_temp_dir().'/inline.php');

-        $classes = array(WarmedClass::class);
-        $excluded = array(DeclaredClass::class);
+        $classes = [WarmedClass::class];
+        $excluded = [DeclaredClass::class];

        ClassCollectionLoader::inline($classes, $cache, $excluded);

--- a/Tests/ClassLoaderTest.php
+++ b/Tests/ClassLoaderTest.php
@@ -11,16 +11,20 @@

 namespace Symfony\Component\ClassLoader\Tests;

+use PHPUnit\Framework\TestCase;
 use Symfony\Component\ClassLoader\ClassLoader;

-class ClassLoaderTest extends \PHPUnit_Framework_TestCase
+/**
+ * @group legacy
+ */
+class ClassLoaderTest extends TestCase
 {
    public function testGetPrefixes()
    {
        $loader = new ClassLoader();
-        $loader->addPrefix('Foo', __DIR__.DIRECTORY_SEPARATOR.'Fixtures');
-        $loader->addPrefix('Bar', __DIR__.DIRECTORY_SEPARATOR.'Fixtures');
-        $loader->addPrefix('Bas', __DIR__.DIRECTORY_SEPARATOR.'Fixtures');
+        $loader->addPrefix('Foo', __DIR__.\DIRECTORY_SEPARATOR.'Fixtures');
+        $loader->addPrefix('Bar', __DIR__.\DIRECTORY_SEPARATOR.'Fixtures');
+        $loader->addPrefix('Bas', __DIR__.\DIRECTORY_SEPARATOR.'Fixtures');
        $prefixes = $loader->getPrefixes();
        $this->assertArrayHasKey('Foo', $prefixes);
        $this->assertArrayNotHasKey('Foo1', $prefixes);
@@ -31,8 +35,8 @@ class ClassLoaderTest extends \PHPUnit_Framework_TestCase
    public function testGetFallbackDirs()
    {
        $loader = new ClassLoader();
-        $loader->addPrefix(null, __DIR__.DIRECTORY_SEPARATOR.'Fixtures');
-        $loader->addPrefix(null, __DIR__.DIRECTORY_SEPARATOR.'Fixtures');
+        $loader->addPrefix(null, __DIR__.\DIRECTORY_SEPARATOR.'Fixtures');
+        $loader->addPrefix(null, __DIR__.\DIRECTORY_SEPARATOR.'Fixtures');
        $fallback_dirs = $loader->getFallbackDirs();
        $this->assertCount(2, $fallback_dirs);
    }
@@ -43,18 +47,18 @@ class ClassLoaderTest extends \PHPUnit_Framework_TestCase
    public function testLoadClass($className, $testClassName, $message)
    {
        $loader = new ClassLoader();
-        $loader->addPrefix('Namespaced2\\', __DIR__.DIRECTORY_SEPARATOR.'Fixtures');
-        $loader->addPrefix('Pearlike2_', __DIR__.DIRECTORY_SEPARATOR.'Fixtures');
+        $loader->addPrefix('Namespaced2\\', __DIR__.\DIRECTORY_SEPARATOR.'Fixtures');
+        $loader->addPrefix('Pearlike2_', __DIR__.\DIRECTORY_SEPARATOR.'Fixtures');
        $loader->loadClass($testClassName);
        $this->assertTrue(class_exists($className), $message);
    }

    public function getLoadClassTests()
    {
-        return array(
-            array('\\Namespaced2\\Foo', 'Namespaced2\\Foo',   '->loadClass() loads Namespaced2\Foo class'),
-            array('\\Pearlike2_Foo',    'Pearlike2_Foo',      '->loadClass() loads Pearlike2_Foo class'),
-        );
+        return [
+            ['\\Namespaced2\\Foo', 'Namespaced2\\Foo',   '->loadClass() loads Namespaced2\Foo class'],
+            ['\\Pearlike2_Foo',    'Pearlike2_Foo',      '->loadClass() loads Pearlike2_Foo class'],
+        ];
    }

    /**
@@ -63,24 +67,24 @@ class ClassLoaderTest extends \PHPUnit_Framework_TestCase
    public function testLoadNonexistentClass($className, $testClassName, $message)
    {
        $loader = new ClassLoader();
-        $loader->addPrefix('Namespaced2\\', __DIR__.DIRECTORY_SEPARATOR.'Fixtures');
-        $loader->addPrefix('Pearlike2_', __DIR__.DIRECTORY_SEPARATOR.'Fixtures');
+        $loader->addPrefix('Namespaced2\\', __DIR__.\DIRECTORY_SEPARATOR.'Fixtures');
+        $loader->addPrefix('Pearlike2_', __DIR__.\DIRECTORY_SEPARATOR.'Fixtures');
        $loader->loadClass($testClassName);
        $this->assertFalse(class_exists($className), $message);
    }

    public function getLoadNonexistentClassTests()
    {
-        return array(
-            array('\\Pearlike3_Bar', '\\Pearlike3_Bar', '->loadClass() loads non existing Pearlike3_Bar class with a leading slash'),
-        );
+        return [
+            ['\\Pearlike3_Bar', '\\Pearlike3_Bar', '->loadClass() loads non existing Pearlike3_Bar class with a leading slash'],
+        ];
    }

    public function testAddPrefixSingle()
    {
        $loader = new ClassLoader();
-        $loader->addPrefix('Foo', __DIR__.DIRECTORY_SEPARATOR.'Fixtures');
-        $loader->addPrefix('Foo', __DIR__.DIRECTORY_SEPARATOR.'Fixtures');
+        $loader->addPrefix('Foo', __DIR__.\DIRECTORY_SEPARATOR.'Fixtures');
+        $loader->addPrefix('Foo', __DIR__.\DIRECTORY_SEPARATOR.'Fixtures');
        $prefixes = $loader->getPrefixes();
        $this->assertArrayHasKey('Foo', $prefixes);
        $this->assertCount(1, $prefixes['Foo']);
@@ -89,8 +93,8 @@ class ClassLoaderTest extends \PHPUnit_Framework_TestCase
    public function testAddPrefixesSingle()
    {
        $loader = new ClassLoader();
-        $loader->addPrefixes(array('Foo' => array('foo', 'foo')));
-        $loader->addPrefixes(array('Foo' => array('foo')));
+        $loader->addPrefixes(['Foo' => ['foo', 'foo']]);
+        $loader->addPrefixes(['Foo' => ['foo']]);
        $prefixes = $loader->getPrefixes();
        $this->assertArrayHasKey('Foo', $prefixes);
        $this->assertCount(1, $prefixes['Foo'], print_r($prefixes, true));
@@ -120,9 +124,9 @@ class ClassLoaderTest extends \PHPUnit_Framework_TestCase
        $loader->setUseIncludePath(true);
        $this->assertTrue($loader->getUseIncludePath());

-        set_include_path(__DIR__.'/Fixtures/includepath'.PATH_SEPARATOR.$includePath);
+        set_include_path(__DIR__.'/Fixtures/includepath'.\PATH_SEPARATOR.$includePath);

-        $this->assertEquals(__DIR__.DIRECTORY_SEPARATOR.'Fixtures'.DIRECTORY_SEPARATOR.'includepath'.DIRECTORY_SEPARATOR.'Foo.php', $loader->findFile('Foo'));
+        $this->assertEquals(__DIR__.\DIRECTORY_SEPARATOR.'Fixtures'.\DIRECTORY_SEPARATOR.'includepath'.\DIRECTORY_SEPARATOR.'Foo.php', $loader->findFile('Foo'));

        set_include_path($includePath);
    }
@@ -133,21 +137,21 @@ class ClassLoaderTest extends \PHPUnit_Framework_TestCase
    public function testLoadClassFromFallback($className, $testClassName, $message)
    {
        $loader = new ClassLoader();
-        $loader->addPrefix('Namespaced2\\', __DIR__.DIRECTORY_SEPARATOR.'Fixtures');
-        $loader->addPrefix('Pearlike2_', __DIR__.DIRECTORY_SEPARATOR.'Fixtures');
-        $loader->addPrefix('', array(__DIR__.DIRECTORY_SEPARATOR.'Fixtures/fallback'));
+        $loader->addPrefix('Namespaced2\\', __DIR__.\DIRECTORY_SEPARATOR.'Fixtures');
+        $loader->addPrefix('Pearlike2_', __DIR__.\DIRECTORY_SEPARATOR.'Fixtures');
+        $loader->addPrefix('', [__DIR__.\DIRECTORY_SEPARATOR.'Fixtures/fallback']);
        $loader->loadClass($testClassName);
        $this->assertTrue(class_exists($className), $message);
    }

    public function getLoadClassFromFallbackTests()
    {
-        return array(
-            array('\\Namespaced2\\Baz',    'Namespaced2\\Baz',    '->loadClass() loads Namespaced2\Baz class'),
-            array('\\Pearlike2_Baz',       'Pearlike2_Baz',       '->loadClass() loads Pearlike2_Baz class'),
-            array('\\Namespaced2\\FooBar', 'Namespaced2\\FooBar', '->loadClass() loads Namespaced2\Baz class from fallback dir'),
-            array('\\Pearlike2_FooBar',    'Pearlike2_FooBar',    '->loadClass() loads Pearlike2_Baz class from fallback dir'),
-        );
+        return [
+            ['\\Namespaced2\\Baz',    'Namespaced2\\Baz',    '->loadClass() loads Namespaced2\Baz class'],
+            ['\\Pearlike2_Baz',       'Pearlike2_Baz',       '->loadClass() loads Pearlike2_Baz class'],
+            ['\\Namespaced2\\FooBar', 'Namespaced2\\FooBar', '->loadClass() loads Namespaced2\Baz class from fallback dir'],
+            ['\\Pearlike2_FooBar',    'Pearlike2_FooBar',    '->loadClass() loads Pearlike2_Baz class from fallback dir'],
+        ];
    }

    /**
@@ -164,71 +168,71 @@ class ClassLoaderTest extends \PHPUnit_Framework_TestCase

    public function getLoadClassNamespaceCollisionTests()
    {
-        return array(
-            array(
-                array(
-                    'NamespaceCollision\\C' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/alpha',
-                    'NamespaceCollision\\C\\B' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/beta',
-                ),
+        return [
+            [
+                [
+                    'NamespaceCollision\\C' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/alpha',
+                    'NamespaceCollision\\C\\B' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/beta',
+                ],
                'NamespaceCollision\C\Foo',
                '->loadClass() loads NamespaceCollision\C\Foo from alpha.',
-            ),
-            array(
-                array(
-                    'NamespaceCollision\\C\\B' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/beta',
-                    'NamespaceCollision\\C' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/alpha',
-                ),
+            ],
+            [
+                [
+                    'NamespaceCollision\\C\\B' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/beta',
+                    'NamespaceCollision\\C' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/alpha',
+                ],
                'NamespaceCollision\C\Bar',
                '->loadClass() loads NamespaceCollision\C\Bar from alpha.',
-            ),
-            array(
-                array(
-                    'NamespaceCollision\\C' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/alpha',
-                    'NamespaceCollision\\C\\B' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/beta',
-                ),
+            ],
+            [
+                [
+                    'NamespaceCollision\\C' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/alpha',
+                    'NamespaceCollision\\C\\B' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/beta',
+                ],
                'NamespaceCollision\C\B\Foo',
                '->loadClass() loads NamespaceCollision\C\B\Foo from beta.',
-            ),
-            array(
-                array(
-                    'NamespaceCollision\\C\\B' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/beta',
-                    'NamespaceCollision\\C' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/alpha',
-                ),
+            ],
+            [
+                [
+                    'NamespaceCollision\\C\\B' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/beta',
+                    'NamespaceCollision\\C' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/alpha',
+                ],
                'NamespaceCollision\C\B\Bar',
                '->loadClass() loads NamespaceCollision\C\B\Bar from beta.',
-            ),
-            array(
-                array(
-                    'PrefixCollision_C_' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/alpha',
-                    'PrefixCollision_C_B_' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/beta',
-                ),
+            ],
+            [
+                [
+                    'PrefixCollision_C_' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/alpha',
+                    'PrefixCollision_C_B_' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/beta',
+                ],
                'PrefixCollision_C_Foo',
                '->loadClass() loads PrefixCollision_C_Foo from alpha.',
-            ),
-            array(
-                array(
-                    'PrefixCollision_C_B_' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/beta',
-                    'PrefixCollision_C_' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/alpha',
-                ),
+            ],
+            [
+                [
+                    'PrefixCollision_C_B_' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/beta',
+                    'PrefixCollision_C_' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/alpha',
+                ],
                'PrefixCollision_C_Bar',
                '->loadClass() loads PrefixCollision_C_Bar from alpha.',
-            ),
-            array(
-                array(
-                    'PrefixCollision_C_' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/alpha',
-                    'PrefixCollision_C_B_' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/beta',
-                ),
+            ],
+            [
+                [
+                    'PrefixCollision_C_' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/alpha',
+                    'PrefixCollision_C_B_' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/beta',
+                ],
                'PrefixCollision_C_B_Foo',
                '->loadClass() loads PrefixCollision_C_B_Foo from beta.',
-            ),
-            array(
-                array(
-                    'PrefixCollision_C_B_' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/beta',
-                    'PrefixCollision_C_' => __DIR__.DIRECTORY_SEPARATOR.'Fixtures/alpha',
-                ),
+            ],
+            [
+                [
+                    'PrefixCollision_C_B_' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/beta',
+                    'PrefixCollision_C_' => __DIR__.\DIRECTORY_SEPARATOR.'Fixtures/alpha',
+                ],
                'PrefixCollision_C_B_Bar',
                '->loadClass() loads PrefixCollision_C_B_Bar from beta.',
-            ),
-        );
+            ],
+        ];
    }
 }
--- a/Tests/ClassMapGeneratorTest.php
+++ b/Tests/ClassMapGeneratorTest.php
@@ -11,9 +11,13 @@

 namespace Symfony\Component\ClassLoader\Tests;

+use PHPUnit\Framework\TestCase;
 use Symfony\Component\ClassLoader\ClassMapGenerator;

-class ClassMapGeneratorTest extends \PHPUnit_Framework_TestCase
+/**
+ * @group legacy
+ */
+class ClassMapGeneratorTest extends TestCase
 {
    /**
     * @var string|null
@@ -70,8 +74,8 @@ class ClassMapGeneratorTest extends \PHPUnit_Framework_TestCase

    public function getTestCreateMapTests()
    {
-        $data = array(
-            array(__DIR__.'/Fixtures/Namespaced', array(
+        $data = [
+            [__DIR__.'/Fixtures/Namespaced', [
                'Namespaced\\Bar' => realpath(__DIR__).'/Fixtures/Namespaced/Bar.php',
                'Namespaced\\Foo' => realpath(__DIR__).'/Fixtures/Namespaced/Foo.php',
                'Namespaced\\Baz' => realpath(__DIR__).'/Fixtures/Namespaced/Baz.php',
@@ -80,20 +84,20 @@ class ClassMapGeneratorTest extends \PHPUnit_Framework_TestCase
                'Namespaced\\WithHaltCompiler' => realpath(__DIR__).'/Fixtures/Namespaced/WithHaltCompiler.php',
                'Namespaced\\WithDirMagic' => realpath(__DIR__).'/Fixtures/Namespaced/WithDirMagic.php',
                'Namespaced\\WithFileMagic' => realpath(__DIR__).'/Fixtures/Namespaced/WithFileMagic.php',
-            )),
-            array(__DIR__.'/Fixtures/beta/NamespaceCollision', array(
+            ]],
+            [__DIR__.'/Fixtures/beta/NamespaceCollision', [
                'NamespaceCollision\\A\\B\\Bar' => realpath(__DIR__).'/Fixtures/beta/NamespaceCollision/A/B/Bar.php',
                'NamespaceCollision\\A\\B\\Foo' => realpath(__DIR__).'/Fixtures/beta/NamespaceCollision/A/B/Foo.php',
                'NamespaceCollision\\C\\B\\Bar' => realpath(__DIR__).'/Fixtures/beta/NamespaceCollision/C/B/Bar.php',
                'NamespaceCollision\\C\\B\\Foo' => realpath(__DIR__).'/Fixtures/beta/NamespaceCollision/C/B/Foo.php',
-            )),
-            array(__DIR__.'/Fixtures/Pearlike', array(
+            ]],
+            [__DIR__.'/Fixtures/Pearlike', [
                'Pearlike_Foo' => realpath(__DIR__).'/Fixtures/Pearlike/Foo.php',
                'Pearlike_Bar' => realpath(__DIR__).'/Fixtures/Pearlike/Bar.php',
                'Pearlike_Baz' => realpath(__DIR__).'/Fixtures/Pearlike/Baz.php',
                'Pearlike_WithComments' => realpath(__DIR__).'/Fixtures/Pearlike/WithComments.php',
-            )),
-            array(__DIR__.'/Fixtures/classmap', array(
+            ]],
+            [__DIR__.'/Fixtures/classmap', [
                'Foo\\Bar\\A' => realpath(__DIR__).'/Fixtures/classmap/sameNsMultipleClasses.php',
                'Foo\\Bar\\B' => realpath(__DIR__).'/Fixtures/classmap/sameNsMultipleClasses.php',
                'A' => realpath(__DIR__).'/Fixtures/classmap/multipleNs.php',
@@ -104,19 +108,19 @@ class ClassMapGeneratorTest extends \PHPUnit_Framework_TestCase
                'ClassMap\\SomeInterface' => realpath(__DIR__).'/Fixtures/classmap/SomeInterface.php',
                'ClassMap\\SomeParent' => realpath(__DIR__).'/Fixtures/classmap/SomeParent.php',
                'ClassMap\\SomeClass' => realpath(__DIR__).'/Fixtures/classmap/SomeClass.php',
-            )),
-            array(__DIR__.'/Fixtures/php5.4', array(
+            ]],
+            [__DIR__.'/Fixtures/php5.4', [
                'TFoo' => __DIR__.'/Fixtures/php5.4/traits.php',
                'CFoo' => __DIR__.'/Fixtures/php5.4/traits.php',
                'Foo\\TBar' => __DIR__.'/Fixtures/php5.4/traits.php',
                'Foo\\IBar' => __DIR__.'/Fixtures/php5.4/traits.php',
                'Foo\\TFooBar' => __DIR__.'/Fixtures/php5.4/traits.php',
                'Foo\\CBar' => __DIR__.'/Fixtures/php5.4/traits.php',
-            )),
-            array(__DIR__.'/Fixtures/php5.5', array(
+            ]],
+            [__DIR__.'/Fixtures/php5.5', [
                'ClassCons\\Foo' => __DIR__.'/Fixtures/php5.5/class_cons.php',
-            )),
-        );
+            ]],
+        ];

        return $data;
    }
@@ -126,15 +130,15 @@ class ClassMapGeneratorTest extends \PHPUnit_Framework_TestCase
        $finder = new \Symfony\Component\Finder\Finder();
        $finder->files()->in(__DIR__.'/Fixtures/beta/NamespaceCollision');

-        $this->assertEqualsNormalized(array(
+        $this->assertEqualsNormalized([
            'NamespaceCollision\\A\\B\\Bar' => realpath(__DIR__).'/Fixtures/beta/NamespaceCollision/A/B/Bar.php',
            'NamespaceCollision\\A\\B\\Foo' => realpath(__DIR__).'/Fixtures/beta/NamespaceCollision/A/B/Foo.php',
            'NamespaceCollision\\C\\B\\Bar' => realpath(__DIR__).'/Fixtures/beta/NamespaceCollision/C/B/Bar.php',
            'NamespaceCollision\\C\\B\\Foo' => realpath(__DIR__).'/Fixtures/beta/NamespaceCollision/C/B/Foo.php',
-        ), ClassMapGenerator::createMap($finder));
+        ], ClassMapGenerator::createMap($finder));
    }

-    protected function assertEqualsNormalized($expected, $actual, $message = null)
+    protected function assertEqualsNormalized($expected, $actual, $message = '')
    {
        foreach ($expected as $ns => $path) {
            $expected[$ns] = str_replace('\\', '/', $path);
--- a/Tests/Psr4ClassLoaderTest.php
+++ b/Tests/Psr4ClassLoaderTest.php
@@ -11,9 +11,13 @@

 namespace Symfony\Component\ClassLoader\Tests;

+use PHPUnit\Framework\TestCase;
 use Symfony\Component\ClassLoader\Psr4ClassLoader;

-class Psr4ClassLoaderTest extends \PHPUnit_Framework_TestCase
+/**
+ * @group legacy
+ */
+class Psr4ClassLoaderTest extends TestCase
 {
    /**
     * @param string $className
@@ -24,7 +28,7 @@ class Psr4ClassLoaderTest extends \PHPUnit_Framework_TestCase
        $loader = new Psr4ClassLoader();
        $loader->addPrefix(
            'Acme\\DemoLib',
-            __DIR__.DIRECTORY_SEPARATOR.'Fixtures'.DIRECTORY_SEPARATOR.'psr-4'
+            __DIR__.\DIRECTORY_SEPARATOR.'Fixtures'.\DIRECTORY_SEPARATOR.'psr-4'
        );
        $loader->loadClass($className);
        $this->assertTrue(class_exists($className), sprintf('loadClass() should load %s', $className));
@@ -35,12 +39,12 @@ class Psr4ClassLoaderTest extends \PHPUnit_Framework_TestCase
     */
    public function getLoadClassTests()
    {
-        return array(
-            array('Acme\\DemoLib\\Foo'),
-            array('Acme\\DemoLib\\Class_With_Underscores'),
-            array('Acme\\DemoLib\\Lets\\Go\\Deeper\\Foo'),
-            array('Acme\\DemoLib\\Lets\\Go\\Deeper\\Class_With_Underscores'),
-        );
+        return [
+            ['Acme\\DemoLib\\Foo'],
+            ['Acme\\DemoLib\\Class_With_Underscores'],
+            ['Acme\\DemoLib\\Lets\\Go\\Deeper\\Foo'],
+            ['Acme\\DemoLib\\Lets\\Go\\Deeper\\Class_With_Underscores'],
+        ];
    }

    /**
@@ -52,7 +56,7 @@ class Psr4ClassLoaderTest extends \PHPUnit_Framework_TestCase
        $loader = new Psr4ClassLoader();
        $loader->addPrefix(
            'Acme\\DemoLib',
-            __DIR__.DIRECTORY_SEPARATOR.'Fixtures'.DIRECTORY_SEPARATOR.'psr-4'
+            __DIR__.\DIRECTORY_SEPARATOR.'Fixtures'.\DIRECTORY_SEPARATOR.'psr-4'
        );
        $loader->loadClass($className);
        $this->assertFalse(class_exists($className), sprintf('loadClass() should not load %s', $className));
@@ -63,9 +67,9 @@ class Psr4ClassLoaderTest extends \PHPUnit_Framework_TestCase
     */
    public function getLoadNonexistentClassTests()
    {
-        return array(
-            array('Acme\\DemoLib\\I_Do_Not_Exist'),
-            array('UnknownVendor\\SomeLib\\I_Do_Not_Exist'),
-        );
+        return [
+            ['Acme\\DemoLib\\I_Do_Not_Exist'],
+            ['UnknownVendor\\SomeLib\\I_Do_Not_Exist'],
+        ];
    }
 }
--- a/WinCacheClassLoader.php
+++ b/WinCacheClassLoader.php
@@ -11,6 +11,8 @@

 namespace Symfony\Component\ClassLoader;

+@trigger_error('The '.__NAMESPACE__.'\WinCacheClassLoader class is deprecated since Symfony 3.3 and will be removed in 4.0. Use `composer install --apcu-autoloader` instead.', \E_USER_DEPRECATED);
+
 /**
 * WinCacheClassLoader implements a wrapping autoloader cached in WinCache.
 *
@@ -43,6 +45,8 @@ namespace Symfony\Component\ClassLoader;
 * @author Fabien Potencier <fabien@symfony.com>
 * @author Kris Wallsmith <kris@symfony.com>
 * @author Artem Ryzhkov <artem@smart-core.org>
+ *
+ * @deprecated since version 3.3, to be removed in 4.0. Use `composer install --apcu-autoloader` instead.
 */
 class WinCacheClassLoader
 {
@@ -56,8 +60,6 @@ class WinCacheClassLoader
    protected $decorated;

    /**
-     * Constructor.
-     *
     * @param string $prefix    The WinCache namespace prefix to use
     * @param object $decorated A class loader object that implements the findFile() method
     *
@@ -66,7 +68,7 @@ class WinCacheClassLoader
     */
    public function __construct($prefix, $decorated)
    {
-        if (!extension_loaded('wincache')) {
+        if (!\extension_loaded('wincache')) {
            throw new \RuntimeException('Unable to use WinCacheClassLoader as WinCache is not enabled.');
        }

@@ -85,7 +87,7 @@ class WinCacheClassLoader
     */
    public function register($prepend = false)
    {
-        spl_autoload_register(array($this, 'loadClass'), true, $prepend);
+        spl_autoload_register([$this, 'loadClass'], true, $prepend);
    }

    /**
@@ -93,7 +95,7 @@ class WinCacheClassLoader
     */
    public function unregister()
    {
-        spl_autoload_unregister(array($this, 'loadClass'));
+        spl_autoload_unregister([$this, 'loadClass']);
    }

    /**
@@ -110,6 +112,8 @@ class WinCacheClassLoader

            return true;
        }
+
+        return null;
    }

    /**
@@ -135,6 +139,6 @@ class WinCacheClassLoader
     */
    public function __call($method, $args)
    {
-        return call_user_func_array(array($this->decorated, $method), $args);
+        return \call_user_func_array([$this->decorated, $method], $args);
    }
 }
--- a/XcacheClassLoader.php
+++ b/XcacheClassLoader.php
@@ -11,6 +11,8 @@

 namespace Symfony\Component\ClassLoader;

+@trigger_error('The '.__NAMESPACE__.'\XcacheClassLoader class is deprecated since Symfony 3.3 and will be removed in 4.0. Use `composer install --apcu-autoloader` instead.', \E_USER_DEPRECATED);
+
 /**
 * XcacheClassLoader implements a wrapping autoloader cached in XCache for PHP 5.3.
 *
@@ -43,21 +45,15 @@ namespace Symfony\Component\ClassLoader;
 * @author Fabien Potencier <fabien@symfony.com>
 * @author Kris Wallsmith <kris@symfony.com>
 * @author Kim Hemsø Rasmussen <kimhemsoe@gmail.com>
+ *
+ * @deprecated since version 3.3, to be removed in 4.0. Use `composer install --apcu-autoloader` instead.
 */
 class XcacheClassLoader
 {
    private $prefix;
-
-    /**
-     * A class loader object that implements the findFile() method.
-     *
-     * @var object
-     */
    private $decorated;

    /**
-     * Constructor.
-     *
     * @param string $prefix    The XCache namespace prefix to use
     * @param object $decorated A class loader object that implements the findFile() method
     *
@@ -66,7 +62,7 @@ class XcacheClassLoader
     */
    public function __construct($prefix, $decorated)
    {
-        if (!extension_loaded('xcache')) {
+        if (!\extension_loaded('xcache')) {
            throw new \RuntimeException('Unable to use XcacheClassLoader as XCache is not enabled.');
        }

@@ -85,7 +81,7 @@ class XcacheClassLoader
     */
    public function register($prepend = false)
    {
-        spl_autoload_register(array($this, 'loadClass'), true, $prepend);
+        spl_autoload_register([$this, 'loadClass'], true, $prepend);
    }

    /**
@@ -93,7 +89,7 @@ class XcacheClassLoader
     */
    public function unregister()
    {
-        spl_autoload_unregister(array($this, 'loadClass'));
+        spl_autoload_unregister([$this, 'loadClass']);
    }

    /**
@@ -110,6 +106,8 @@ class XcacheClassLoader

            return true;
        }
+
+        return null;
    }

    /**
@@ -136,6 +134,6 @@ class XcacheClassLoader
     */
    public function __call($method, $args)
    {
-        return call_user_func_array(array($this->decorated, $method), $args);
+        return \call_user_func_array([$this->decorated, $method], $args);
    }
 }
--- a/composer.json
+++ b/composer.json
@@ -17,10 +17,10 @@
    ],
    "minimum-stability": "dev",
    "require": {
-        "php": ">=5.5.9"
+        "php": "^5.5.9|>=7.0.8"
    },
    "require-dev": {
-        "symfony/finder": "~2.8|~3.0",
+        "symfony/finder": "~2.8|~3.0|~4.0",
        "symfony/polyfill-apcu": "~1.1"
    },
    "suggest": {
@@ -31,10 +31,5 @@
        "exclude-from-classmap": [
            "/Tests/"
        ]
-    },
-    "extra": {
-        "branch-alias": {
-            "dev-master": "3.2-dev"
-        }
    }
 }
--- a/phpunit.xml.dist
+++ b/phpunit.xml.dist
@@ -1,10 +1,12 @@
 <?xml version="1.0" encoding="UTF-8"?>

 <phpunit xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
-         xsi:noNamespaceSchemaLocation="http://schema.phpunit.de/4.1/phpunit.xsd"
+         xsi:noNamespaceSchemaLocation="http://schema.phpunit.de/5.2/phpunit.xsd"
         backupGlobals="false"
         colors="true"
         bootstrap="vendor/autoload.php"
+         failOnRisky="true"
+         failOnWarning="true"
 >
    <php>
        <ini name="error_reporting" value="-1" />