Fix displaying anonymous classes on PHP >= 7.4.2

Merge branch '3.4' into 4.3
* 3.4: [Debug] fix ClassNotFoundFatalErrorHandler [Dotenv] Fixed infinite loop with missing quote followed by quoted value [TwigBridge] button_widget now has its title attr translated even if its label = null or false [PhpUnitBridge] When using phpenv + phpenv-composer plugin, composer executable is wrapped into a bash script [Security] Prevent canceled remember-me cookie from being accepted [FrameworkBundle][TranslationUpdateCommand] Do not output positive feedback on stderr
2026-03-25 09:42:20 +01:00 · 2020-01-25 13:32:28 +01:00 · 2020-01-08 18:19:22 +01:00 · 2020-01-08 17:36:15 +01:00 · 2020-01-04 13:24:57 +01:00 · 2020-01-04 13:05:51 +01:00
33 changed files with 892 additions and 222 deletions
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,14 @@
 CHANGELOG
 =========

+4.3.0
+-----
+
+* made the `ErrorHandler` and `ExceptionHandler` classes final
+* added `Exception\FlattenException::getAsString` and
+`Exception\FlattenException::getTraceAsString` to increase compatibility to php
+exception objects
+
 4.0.0
 -----

--- a/DebugClassLoader.php
+++ b/DebugClassLoader.php
@@ -11,6 +11,8 @@

 namespace Symfony\Component\Debug;

+use PHPUnit\Framework\MockObject\Matcher\StatelessInvocation;
+
 /**
 * Autoloader checking if the class is really defined in the file found.
 *
@@ -21,6 +23,7 @@ namespace Symfony\Component\Debug;
 * @author Fabien Potencier <fabien@symfony.com>
 * @author Christophe Coevoet <stof@notk.org>
 * @author Nicolas Grekas <p@tchwork.com>
+ * @author Guilhem Niot <guilhem.niot@gmail.com>
 */
 class DebugClassLoader
 {
@@ -34,7 +37,9 @@ class DebugClassLoader
    private static $deprecated = [];
    private static $internal = [];
    private static $internalMethods = [];
+    private static $annotatedParameters = [];
    private static $darwinCache = ['/' => ['/', []]];
+    private static $method = [];

    public function __construct(callable $classLoader)
    {
@@ -148,11 +153,11 @@ class DebugClassLoader
                if (!$file = $this->classLoader[0]->findFile($class) ?: false) {
                    // no-op
                } elseif (\function_exists('opcache_is_script_cached') && @opcache_is_script_cached($file)) {
-                    require $file;
+                    include $file;

                    return;
-                } else {
-                    require $file;
+                } elseif (false === include $file) {
+                    return;
                }
            } else {
                ($this->classLoader)($class);
@@ -167,7 +172,7 @@ class DebugClassLoader

    private function checkClass($class, $file = null)
    {
-        $exists = null === $file || \class_exists($class, false) || \interface_exists($class, false) || \trait_exists($class, false);
+        $exists = null === $file || class_exists($class, false) || interface_exists($class, false) || trait_exists($class, false);

        if (null !== $file && $class && '\\' === $class[0]) {
            $class = substr($class, 1);
@@ -185,7 +190,7 @@ class DebugClassLoader
            }
            $name = $refl->getName();

-            if ($name !== $class && 0 === \strcasecmp($name, $class)) {
+            if ($name !== $class && 0 === strcasecmp($name, $class)) {
                throw new \RuntimeException(sprintf('Case mismatch between loaded and declared class names: "%s" vs "%s".', $class, $name));
            }

@@ -218,23 +223,41 @@ class DebugClassLoader
        $deprecations = [];

        // Don't trigger deprecations for classes in the same vendor
-        if (2 > $len = 1 + (\strpos($class, '\\') ?: \strpos($class, '_'))) {
+        if (2 > $len = 1 + (strpos($class, '\\') ?: strpos($class, '_'))) {
            $len = 0;
            $ns = '';
        } else {
-            $ns = \str_replace('_', '\\', \substr($class, 0, $len));
+            $ns = str_replace('_', '\\', substr($class, 0, $len));
        }

        // Detect annotations on the class
        if (false !== $doc = $refl->getDocComment()) {
            foreach (['final', 'deprecated', 'internal'] as $annotation) {
-                if (false !== \strpos($doc, $annotation) && preg_match('#\n\s+\* @'.$annotation.'(?:( .+?)\.?)?\r?\n\s+\*(?: @|/$)#s', $doc, $notice)) {
+                if (false !== strpos($doc, $annotation) && preg_match('#\n\s+\* @'.$annotation.'(?:( .+?)\.?)?\r?\n\s+\*(?: @|/$|\r?\n)#s', $doc, $notice)) {
                    self::${$annotation}[$class] = isset($notice[1]) ? preg_replace('#\.?\r?\n( \*)? *(?= |\r?\n|$)#', '', $notice[1]) : '';
                }
            }
+
+            if ($refl->isInterface() && false !== strpos($doc, 'method') && preg_match_all('#\n \* @method\s+(static\s+)?+(?:[\w\|&\[\]\\\]+\s+)?(\w+(?:\s*\([^\)]*\))?)+(.+?([[:punct:]]\s*)?)?(?=\r?\n \*(?: @|/$|\r?\n))#', $doc, $notice, PREG_SET_ORDER)) {
+                foreach ($notice as $method) {
+                    $static = '' !== $method[1];
+                    $name = $method[2];
+                    $description = $method[3] ?? null;
+                    if (false === strpos($name, '(')) {
+                        $name .= '()';
+                    }
+                    if (null !== $description) {
+                        $description = trim($description);
+                        if (!isset($method[4])) {
+                            $description .= '.';
+                        }
+                    }
+                    self::$method[$class][] = [$class, $name, $static, $description];
+                }
+            }
        }

-        $parent = \get_parent_class($class);
+        $parent = get_parent_class($class);
        $parentAndOwnInterfaces = $this->getOwnInterfaces($class, $parent);
        if ($parent) {
            $parentAndOwnInterfaces[$parent] = $parent;
@@ -249,30 +272,53 @@ class DebugClassLoader
        }

        // Detect if the parent is annotated
-        foreach ($parentAndOwnInterfaces + \class_uses($class, false) as $use) {
+        foreach ($parentAndOwnInterfaces + class_uses($class, false) as $use) {
            if (!isset(self::$checkedClasses[$use])) {
                $this->checkClass($use);
            }
-            if (isset(self::$deprecated[$use]) && \strncmp($ns, \str_replace('_', '\\', $use), $len)) {
+            if (isset(self::$deprecated[$use]) && strncmp($ns, str_replace('_', '\\', $use), $len) && !isset(self::$deprecated[$class])) {
                $type = class_exists($class, false) ? 'class' : (interface_exists($class, false) ? 'interface' : 'trait');
                $verb = class_exists($use, false) || interface_exists($class, false) ? 'extends' : (interface_exists($use, false) ? 'implements' : 'uses');

                $deprecations[] = sprintf('The "%s" %s %s "%s" that is deprecated%s.', $class, $type, $verb, $use, self::$deprecated[$use]);
            }
-            if (isset(self::$internal[$use]) && \strncmp($ns, \str_replace('_', '\\', $use), $len)) {
+            if (isset(self::$internal[$use]) && strncmp($ns, str_replace('_', '\\', $use), $len)) {
                $deprecations[] = sprintf('The "%s" %s is considered internal%s. It may change without further notice. You should not use it from "%s".', $use, class_exists($use, false) ? 'class' : (interface_exists($use, false) ? 'interface' : 'trait'), self::$internal[$use], $class);
            }
+            if (isset(self::$method[$use])) {
+                if ($refl->isAbstract()) {
+                    if (isset(self::$method[$class])) {
+                        self::$method[$class] = array_merge(self::$method[$class], self::$method[$use]);
+                    } else {
+                        self::$method[$class] = self::$method[$use];
+                    }
+                } elseif (!$refl->isInterface()) {
+                    $hasCall = $refl->hasMethod('__call');
+                    $hasStaticCall = $refl->hasMethod('__callStatic');
+                    foreach (self::$method[$use] as $method) {
+                        list($interface, $name, $static, $description) = $method;
+                        if ($static ? $hasStaticCall : $hasCall) {
+                            continue;
+                        }
+                        $realName = substr($name, 0, strpos($name, '('));
+                        if (!$refl->hasMethod($realName) || !($methodRefl = $refl->getMethod($realName))->isPublic() || ($static && !$methodRefl->isStatic()) || (!$static && $methodRefl->isStatic())) {
+                            $deprecations[] = sprintf('Class "%s" should implement method "%s::%s"%s', $class, ($static ? 'static ' : '').$interface, $name, null == $description ? '.' : ': '.$description);
+                        }
+                    }
+                }
+            }
        }

-        if (\trait_exists($class)) {
+        if (trait_exists($class)) {
            return $deprecations;
        }

-        // Inherit @final and @internal annotations for methods
+        // Inherit @final, @internal and @param annotations for methods
        self::$finalMethods[$class] = [];
        self::$internalMethods[$class] = [];
+        self::$annotatedParameters[$class] = [];
        foreach ($parentAndOwnInterfaces as $use) {
-            foreach (['finalMethods', 'internalMethods'] as $property) {
+            foreach (['finalMethods', 'internalMethods', 'annotatedParameters'] as $property) {
                if (isset(self::${$property}[$use])) {
                    self::${$property}[$class] = self::${$property}[$class] ? self::${$property}[$use] + self::${$property}[$class] : self::${$property}[$use];
                }
@@ -291,20 +337,57 @@ class DebugClassLoader

            if (isset(self::$internalMethods[$class][$method->name])) {
                list($declaringClass, $message) = self::$internalMethods[$class][$method->name];
-                if (\strncmp($ns, $declaringClass, $len)) {
+                if (strncmp($ns, $declaringClass, $len)) {
                    $deprecations[] = sprintf('The "%s::%s()" method is considered internal%s. It may change without further notice. You should not extend it from "%s".', $declaringClass, $method->name, $message, $class);
                }
            }

-            // Detect method annotations
-            if (false === $doc = $method->getDocComment()) {
+            // To read method annotations
+            $doc = $method->getDocComment();
+
+            if (isset(self::$annotatedParameters[$class][$method->name])) {
+                $definedParameters = [];
+                foreach ($method->getParameters() as $parameter) {
+                    $definedParameters[$parameter->name] = true;
+                }
+
+                foreach (self::$annotatedParameters[$class][$method->name] as $parameterName => $deprecation) {
+                    if (!isset($definedParameters[$parameterName]) && !($doc && preg_match("/\\n\\s+\\* @param +((?(?!callable *\().*?|callable *\(.*\).*?))(?<= )\\\${$parameterName}\\b/", $doc))) {
+                        $deprecations[] = sprintf($deprecation, $class);
+                    }
+                }
+            }
+
+            if (!$doc) {
                continue;
            }

+            $finalOrInternal = false;
+
            foreach (['final', 'internal'] as $annotation) {
-                if (false !== \strpos($doc, $annotation) && preg_match('#\n\s+\* @'.$annotation.'(?:( .+?)\.?)?\r?\n\s+\*(?: @|/$)#s', $doc, $notice)) {
+                if (false !== strpos($doc, $annotation) && preg_match('#\n\s+\* @'.$annotation.'(?:( .+?)\.?)?\r?\n\s+\*(?: @|/$|\r?\n)#s', $doc, $notice)) {
                    $message = isset($notice[1]) ? preg_replace('#\.?\r?\n( \*)? *(?= |\r?\n|$)#', '', $notice[1]) : '';
                    self::${$annotation.'Methods'}[$class][$method->name] = [$class, $message];
+                    $finalOrInternal = true;
+                }
+            }
+
+            if ($finalOrInternal || $method->isConstructor() || false === strpos($doc, '@param') || StatelessInvocation::class === $class) {
+                continue;
+            }
+            if (!preg_match_all('#\n\s+\* @param +((?(?!callable *\().*?|callable *\(.*\).*?))(?<= )\$([a-zA-Z0-9_\x7f-\xff]++)#', $doc, $matches, PREG_SET_ORDER)) {
+                continue;
+            }
+            if (!isset(self::$annotatedParameters[$class][$method->name])) {
+                $definedParameters = [];
+                foreach ($method->getParameters() as $parameter) {
+                    $definedParameters[$parameter->name] = true;
+                }
+            }
+            foreach ($matches as list(, $parameterType, $parameterName)) {
+                if (!isset($definedParameters[$parameterName])) {
+                    $parameterType = trim($parameterType);
+                    self::$annotatedParameters[$class][$method->name][$parameterName] = sprintf('The "%%s::%s()" method will require a new "%s$%s" argument in the next major version of its parent class "%s", not defining it is deprecated.', $method->name, $parameterType ? $parameterType.' ' : '', $parameterName, $method->class);
                }
            }
        }
@@ -312,6 +395,12 @@ class DebugClassLoader
        return $deprecations;
    }

+    /**
+     * @param string $file
+     * @param string $class
+     *
+     * @return array|null
+     */
    public function checkCase(\ReflectionClass $refl, $file, $class)
    {
        $real = explode('\\', $class.strrchr($file, '.'));
@@ -328,7 +417,7 @@ class DebugClassLoader
        array_splice($tail, 0, $i + 1);

        if (!$tail) {
-            return;
+            return null;
        }

        $tail = \DIRECTORY_SEPARATOR.implode(\DIRECTORY_SEPARATOR, $tail);
@@ -344,6 +433,8 @@ class DebugClassLoader
        ) {
            return [substr($tail, -$tailLen + 1), substr($real, -$tailLen + 1), substr($real, 0, -$tailLen + 1)];
        }
+
+        return null;
    }

    /**
@@ -364,7 +455,11 @@ class DebugClassLoader
                $real = self::$darwinCache[$kDir][0];
            } else {
                $dir = getcwd();
-                chdir($real);
+
+                if (!@chdir($real)) {
+                    return $real.$file;
+                }
+
                $real = getcwd().'/';
                chdir($dir);

@@ -385,8 +480,13 @@ class DebugClassLoader

        $dirFiles = self::$darwinCache[$kDir][1];

+        if (!isset($dirFiles[$file]) && ') : eval()\'d code' === substr($file, -17)) {
+            // Get the file name from "file_name.php(123) : eval()'d code"
+            $file = substr($file, 0, strrpos($file, '(', -17));
+        }
+
        if (isset($dirFiles[$file])) {
-            return $real .= $dirFiles[$file];
+            return $real.$dirFiles[$file];
        }

        $kFile = strtolower($file);
@@ -405,7 +505,7 @@ class DebugClassLoader
            self::$darwinCache[$kDir][1] = $dirFiles;
        }

-        return $real .= $dirFiles[$kFile];
+        return $real.$dirFiles[$kFile];
    }

    /**
--- a/ErrorHandler.php
+++ b/ErrorHandler.php
@@ -15,6 +15,7 @@ use Psr\Log\LoggerInterface;
 use Psr\Log\LogLevel;
 use Symfony\Component\Debug\Exception\FatalErrorException;
 use Symfony\Component\Debug\Exception\FatalThrowableError;
+use Symfony\Component\Debug\Exception\FlattenException;
 use Symfony\Component\Debug\Exception\OutOfMemoryException;
 use Symfony\Component\Debug\Exception\SilencedErrorContext;
 use Symfony\Component\Debug\FatalErrorHandler\ClassNotFoundFatalErrorHandler;
@@ -44,6 +45,8 @@ use Symfony\Component\Debug\FatalErrorHandler\UndefinedMethodFatalErrorHandler;
 *
 * @author Nicolas Grekas <p@tchwork.com>
 * @author Grégoire Pineau <lyrixx@lyrixx.info>
+ *
+ * @final since Symfony 4.3
 */
 class ErrorHandler
 {
@@ -219,7 +222,7 @@ class ErrorHandler
            }
            if (!\is_array($log)) {
                $log = [$log];
-            } elseif (!array_key_exists(0, $log)) {
+            } elseif (!\array_key_exists(0, $log)) {
                throw new \InvalidArgumentException('No logger provided');
            }
            if (null === $log[0]) {
@@ -379,6 +382,10 @@ class ErrorHandler
     */
    public function handleError($type, $message, $file, $line)
    {
+        if (\PHP_VERSION_ID >= 70300 && E_WARNING === $type && '"' === $message[0] && false !== strpos($message, '" targeting switch is equivalent to "break')) {
+            $type = E_DEPRECATED;
+        }
+
        // Level is the current error reporting level to manage silent error.
        $level = error_reporting();
        $silenced = 0 === ($level & $type);
@@ -405,15 +412,19 @@ class ErrorHandler
            $context = $e;
        }

-        $logMessage = $this->levels[$type].': '.$message;
+        if (false !== strpos($message, "class@anonymous\0")) {
+            $logMessage = $this->levels[$type].': '.(new FlattenException())->setMessage($message)->getMessage();
+        } else {
+            $logMessage = $this->levels[$type].': '.$message;
+        }

        if (null !== self::$toStringException) {
            $errorAsException = self::$toStringException;
            self::$toStringException = null;
        } elseif (!$throw && !($type & $level)) {
            if (!isset(self::$silencedErrorCache[$id = $file.':'.$line])) {
-                $lightTrace = $this->tracedErrors & $type ? $this->cleanTrace(debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 3), $type, $file, $line, false) : [];
-                $errorAsException = new SilencedErrorContext($type, $file, $line, $lightTrace);
+                $lightTrace = $this->tracedErrors & $type ? $this->cleanTrace(debug_backtrace(DEBUG_BACKTRACE_IGNORE_ARGS, 5), $type, $file, $line, false) : [];
+                $errorAsException = new SilencedErrorContext($type, $file, $line, isset($lightTrace[1]) ? [$lightTrace[0]] : $lightTrace);
            } elseif (isset(self::$silencedErrorCache[$id][$message])) {
                $lightTrace = null;
                $errorAsException = self::$silencedErrorCache[$id][$message];
@@ -431,12 +442,11 @@ class ErrorHandler
                self::$silencedErrorCache[$id][$message] = $errorAsException;
            }
            if (null === $lightTrace) {
-                return;
+                return true;
            }
        } else {
            $errorAsException = new \ErrorException($logMessage, 0, $type, $file, $line);

-            // Clean the trace by removing function arguments and the first frames added by the error handler itself.
            if ($throw || $this->tracedErrors & $type) {
                $backtrace = $errorAsException->getTrace();
                $lightTrace = $this->cleanTrace($backtrace, $type, $file, $line, $throw);
@@ -448,7 +458,7 @@ class ErrorHandler
        }

        if ($throw) {
-            if (E_USER_ERROR & $type) {
+            if (\PHP_VERSION_ID < 70400 && E_USER_ERROR & $type) {
                for ($i = 1; isset($backtrace[$i]); ++$i) {
                    if (isset($backtrace[$i]['function'], $backtrace[$i]['type'], $backtrace[$i - 1]['function'])
                        && '__toString' === $backtrace[$i]['function']
@@ -486,6 +496,11 @@ class ErrorHandler
        if ($this->isRecursive) {
            $log = 0;
        } else {
+            if (!\defined('HHVM_VERSION')) {
+                $currentErrorHandler = set_error_handler('var_dump');
+                restore_error_handler();
+            }
+
            try {
                $this->isRecursive = true;
                $level = ($type & $level) ? $this->loggers[$type][1] : LogLevel::DEBUG;
@@ -494,7 +509,7 @@ class ErrorHandler
                $this->isRecursive = false;

                if (!\defined('HHVM_VERSION')) {
-                    set_error_handler([$this, __FUNCTION__]);
+                    set_error_handler($currentErrorHandler);
                }
            }
        }
@@ -522,21 +537,24 @@ class ErrorHandler
        $handlerException = null;

        if (($this->loggedErrors & $type) || $exception instanceof FatalThrowableError) {
+            if (false !== strpos($message = $exception->getMessage(), "class@anonymous\0")) {
+                $message = (new FlattenException())->setMessage($message)->getMessage();
+            }
            if ($exception instanceof FatalErrorException) {
                if ($exception instanceof FatalThrowableError) {
                    $error = [
                        'type' => $type,
-                        'message' => $message = $exception->getMessage(),
+                        'message' => $message,
                        'file' => $exception->getFile(),
                        'line' => $exception->getLine(),
                    ];
                } else {
-                    $message = 'Fatal '.$exception->getMessage();
+                    $message = 'Fatal '.$message;
                }
            } elseif ($exception instanceof \ErrorException) {
-                $message = 'Uncaught '.$exception->getMessage();
+                $message = 'Uncaught '.$message;
            } else {
-                $message = 'Uncaught Exception: '.$exception->getMessage();
+                $message = 'Uncaught Exception: '.$message;
            }
        }
        if ($this->loggedErrors & $type) {
@@ -557,7 +575,9 @@ class ErrorHandler
        $this->exceptionHandler = null;
        try {
            if (null !== $exceptionHandler) {
-                return $exceptionHandler($exception);
+                $exceptionHandler($exception);
+
+                return;
            }
            $handlerException = $handlerException ?: $exception;
        } catch (\Throwable $handlerException) {
@@ -665,6 +685,9 @@ class ErrorHandler
        ];
    }

+    /**
+     * Cleans the trace by removing function arguments and the frames added by the error handler and DebugClassLoader.
+     */
    private function cleanTrace($backtrace, $type, $file, $line, $throw)
    {
        $lightTrace = $backtrace;
@@ -675,6 +698,13 @@ class ErrorHandler
                break;
            }
        }
+        if (class_exists(DebugClassLoader::class, false)) {
+            for ($i = \count($lightTrace) - 2; 0 < $i; --$i) {
+                if (DebugClassLoader::class === ($lightTrace[$i]['class'] ?? null)) {
+                    array_splice($lightTrace, --$i, 2);
+                }
+            }
+        }
        if (!($throw || $this->scopedErrors & $type)) {
            for ($i = 0; isset($lightTrace[$i]); ++$i) {
                unset($lightTrace[$i]['args'], $lightTrace[$i]['object']);
--- a/Exception/FlattenException.php
+++ b/Exception/FlattenException.php
@@ -27,6 +27,7 @@ class FlattenException
    private $code;
    private $previous;
    private $trace;
+    private $traceAsString;
    private $class;
    private $statusCode;
    private $headers;
@@ -90,9 +91,14 @@ class FlattenException
        return $this->statusCode;
    }

+    /**
+     * @return $this
+     */
    public function setStatusCode($code)
    {
        $this->statusCode = $code;
+
+        return $this;
    }

    public function getHeaders()
@@ -100,9 +106,14 @@ class FlattenException
        return $this->headers;
    }

+    /**
+     * @return $this
+     */
    public function setHeaders(array $headers)
    {
        $this->headers = $headers;
+
+        return $this;
    }

    public function getClass()
@@ -110,9 +121,14 @@ class FlattenException
        return $this->class;
    }

+    /**
+     * @return $this
+     */
    public function setClass($class)
    {
-        $this->class = $class;
+        $this->class = 'c' === $class[0] && 0 === strpos($class, "class@anonymous\0") ? get_parent_class($class).'@anonymous' : $class;
+
+        return $this;
    }

    public function getFile()
@@ -120,9 +136,14 @@ class FlattenException
        return $this->file;
    }

+    /**
+     * @return $this
+     */
    public function setFile($file)
    {
        $this->file = $file;
+
+        return $this;
    }

    public function getLine()
@@ -130,9 +151,14 @@ class FlattenException
        return $this->line;
    }

+    /**
+     * @return $this
+     */
    public function setLine($line)
    {
        $this->line = $line;
+
+        return $this;
    }

    public function getMessage()
@@ -140,9 +166,20 @@ class FlattenException
        return $this->message;
    }

+    /**
+     * @return $this
+     */
    public function setMessage($message)
    {
+        if (false !== strpos($message, "class@anonymous\0")) {
+            $message = preg_replace_callback('/class@anonymous\x00.*?\.php(?:0x?|:[0-9]++\$)[0-9a-fA-F]++/', function ($m) {
+                return class_exists($m[0], false) ? get_parent_class($m[0]).'@anonymous' : $m[0];
+            }, $message);
+        }
+
        $this->message = $message;
+
+        return $this;
    }

    public function getCode()
@@ -150,9 +187,14 @@ class FlattenException
        return $this->code;
    }

+    /**
+     * @return $this
+     */
    public function setCode($code)
    {
        $this->code = $code;
+
+        return $this;
    }

    public function getPrevious()
@@ -160,9 +202,14 @@ class FlattenException
        return $this->previous;
    }

+    /**
+     * @return $this
+     */
    public function setPrevious(self $previous)
    {
        $this->previous = $previous;
+
+        return $this;
    }

    public function getAllPrevious()
@@ -191,11 +238,16 @@ class FlattenException
        $this->setTraceFromThrowable($exception);
    }

-    public function setTraceFromThrowable(\Throwable $throwable): void
+    public function setTraceFromThrowable(\Throwable $throwable)
    {
-        $this->setTrace($throwable->getTrace(), $throwable->getFile(), $throwable->getLine());
+        $this->traceAsString = $throwable->getTraceAsString();
+
+        return $this->setTrace($throwable->getTrace(), $throwable->getFile(), $throwable->getLine());
    }

+    /**
+     * @return $this
+     */
    public function setTrace($trace, $file, $line)
    {
        $this->trace = [];
@@ -229,6 +281,8 @@ class FlattenException
                'args' => isset($entry['args']) ? $this->flattenArgs($entry['args']) : [],
            ];
        }
+
+        return $this;
    }

    private function flattenArgs($args, $level = 0, &$count = 0)
@@ -273,4 +327,33 @@ class FlattenException

        return $array['__PHP_Incomplete_Class_Name'];
    }
+
+    public function getTraceAsString()
+    {
+        return $this->traceAsString;
+    }
+
+    public function getAsString()
+    {
+        $message = '';
+        $next = false;
+
+        foreach (array_reverse(array_merge([$this], $this->getAllPrevious())) as $exception) {
+            if ($next) {
+                $message .= 'Next ';
+            } else {
+                $next = true;
+            }
+            $message .= $exception->getClass();
+
+            if ('' != $exception->getMessage()) {
+                $message .= ': '.$exception->getMessage();
+            }
+
+            $message .= ' in '.$exception->getFile().':'.$exception->getLine().
+                "\nStack trace:\n".$exception->getTraceAsString()."\n\n";
+        }
+
+        return rtrim($message);
+    }
 }
--- a/Exception/SilencedErrorContext.php
+++ b/Exception/SilencedErrorContext.php
@@ -54,7 +54,7 @@ class SilencedErrorContext implements \JsonSerializable
        return $this->trace;
    }

-    public function JsonSerialize()
+    public function jsonSerialize()
    {
        return [
            'severity' => $this->severity,
--- a/ExceptionHandler.php
+++ b/ExceptionHandler.php
--- a/FatalErrorHandler/ClassNotFoundFatalErrorHandler.php
+++ b/FatalErrorHandler/ClassNotFoundFatalErrorHandler.php
@@ -33,11 +33,11 @@ class ClassNotFoundFatalErrorHandler implements FatalErrorHandlerInterface
        $notFoundSuffix = '\' not found';
        $notFoundSuffixLen = \strlen($notFoundSuffix);
        if ($notFoundSuffixLen > $messageLen) {
-            return;
+            return null;
        }

        if (0 !== substr_compare($error['message'], $notFoundSuffix, -$notFoundSuffixLen)) {
-            return;
+            return null;
        }

        foreach (['class', 'interface', 'trait'] as $typeName) {
@@ -71,6 +71,8 @@ class ClassNotFoundFatalErrorHandler implements FatalErrorHandlerInterface

            return new ClassNotFoundException($message, $exception);
        }
+
+        return null;
    }

    /**
@@ -171,7 +173,11 @@ class ClassNotFoundFatalErrorHandler implements FatalErrorHandlerInterface
            }
        }

-        require_once $file;
+        try {
+            require_once $file;
+        } catch (\Throwable $e) {
+            return null;
+        }

        foreach ($candidates as $candidate) {
            if ($this->classExists($candidate)) {
--- a/FatalErrorHandler/UndefinedFunctionFatalErrorHandler.php
+++ b/FatalErrorHandler/UndefinedFunctionFatalErrorHandler.php
@@ -30,17 +30,17 @@ class UndefinedFunctionFatalErrorHandler implements FatalErrorHandlerInterface
        $notFoundSuffix = '()';
        $notFoundSuffixLen = \strlen($notFoundSuffix);
        if ($notFoundSuffixLen > $messageLen) {
-            return;
+            return null;
        }

        if (0 !== substr_compare($error['message'], $notFoundSuffix, -$notFoundSuffixLen)) {
-            return;
+            return null;
        }

        $prefix = 'Call to undefined function ';
        $prefixLen = \strlen($prefix);
        if (0 !== strpos($error['message'], $prefix)) {
-            return;
+            return null;
        }

        $fullyQualifiedFunctionName = substr($error['message'], $prefixLen, -$notFoundSuffixLen);
--- a/FatalErrorHandler/UndefinedMethodFatalErrorHandler.php
+++ b/FatalErrorHandler/UndefinedMethodFatalErrorHandler.php
@@ -28,7 +28,7 @@ class UndefinedMethodFatalErrorHandler implements FatalErrorHandlerInterface
    {
        preg_match('/^Call to undefined method (.*)::(.*)\(\)$/', $error['message'], $matches);
        if (!$matches) {
-            return;
+            return null;
        }

        $className = $matches[1];
--- a/2
+++ b/2
@@ -1,4 +1,4 @@
-Copyright (c) 2004-2019 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/README.md
+++ b/README.md
@@ -6,7 +6,7 @@ The Debug component provides tools to ease debugging PHP code.
 Resources
 ---------

-  * [Documentation](https://symfony.com/doc/current/components/debug/index.html)
+  * [Documentation](https://symfony.com/doc/current/components/debug.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/DebugClassLoaderTest.php
+++ b/Tests/DebugClassLoaderTest.php
@@ -23,7 +23,7 @@ class DebugClassLoaderTest extends TestCase

    private $loader;

-    protected function setUp()
+    protected function setUp(): void
    {
        $this->errorReporting = error_reporting(E_ALL);
        $this->loader = new ClassLoader();
@@ -31,7 +31,7 @@ class DebugClassLoaderTest extends TestCase
        DebugClassLoader::enable();
    }

-    protected function tearDown()
+    protected function tearDown(): void
    {
        DebugClassLoader::disable();
        spl_autoload_unregister([$this->loader, 'loadClass']);
@@ -44,7 +44,7 @@ class DebugClassLoaderTest extends TestCase

        $functions = spl_autoload_functions();
        foreach ($functions as $function) {
-            if (is_array($function) && $function[0] instanceof DebugClassLoader) {
+            if (\is_array($function) && $function[0] instanceof DebugClassLoader) {
                $reflClass = new \ReflectionClass($function[0]);
                $reflProp = $reflClass->getProperty('classLoader');
                $reflProp->setAccessible(true);
@@ -58,49 +58,43 @@ class DebugClassLoaderTest extends TestCase
        $this->fail('DebugClassLoader did not register');
    }

-    /**
-     * @expectedException \Exception
-     * @expectedExceptionMessage boo
-     */
    public function testThrowingClass()
    {
+        $this->expectException('Exception');
+        $this->expectExceptionMessage('boo');
        try {
-            class_exists(__NAMESPACE__.'\Fixtures\Throwing');
+            class_exists(Fixtures\Throwing::class);
            $this->fail('Exception expected');
        } catch (\Exception $e) {
            $this->assertSame('boo', $e->getMessage());
        }

        // the second call also should throw
-        class_exists(__NAMESPACE__.'\Fixtures\Throwing');
+        class_exists(Fixtures\Throwing::class);
    }

-    /**
-     * @expectedException \RuntimeException
-     */
    public function testNameCaseMismatch()
    {
-        class_exists(__NAMESPACE__.'\TestingCaseMismatch', true);
+        $this->expectException('RuntimeException');
+        $this->expectExceptionMessage('Case mismatch between loaded and declared class names');
+        class_exists(TestingCaseMismatch::class, true);
    }

-    /**
-     * @expectedException \RuntimeException
-     * @expectedExceptionMessage Case mismatch between class and real file names
-     */
    public function testFileCaseMismatch()
    {
+        $this->expectException('RuntimeException');
+        $this->expectExceptionMessage('Case mismatch between class and real file names');
        if (!file_exists(__DIR__.'/Fixtures/CaseMismatch.php')) {
            $this->markTestSkipped('Can only be run on case insensitive filesystems');
        }

-        class_exists(__NAMESPACE__.'\Fixtures\CaseMismatch', true);
+        class_exists(Fixtures\CaseMismatch::class, true);
    }

-    /**
-     * @expectedException \RuntimeException
-     */
    public function testPsr4CaseMismatch()
    {
+        $this->expectException('RuntimeException');
+        $this->expectExceptionMessage('Case mismatch between loaded and declared class names');
        class_exists(__NAMESPACE__.'\Fixtures\Psr4CaseMismatch', true);
    }

@@ -116,7 +110,7 @@ class DebugClassLoaderTest extends TestCase

    public function testClassAlias()
    {
-        $this->assertTrue(class_exists(__NAMESPACE__.'\Fixtures\ClassAlias', true));
+        $this->assertTrue(class_exists(Fixtures\ClassAlias::class, true));
    }

    /**
@@ -158,7 +152,7 @@ class DebugClassLoaderTest extends TestCase
        $e = error_reporting(0);
        trigger_error('', E_USER_NOTICE);

-        class_exists('Test\\'.__NAMESPACE__.'\\NonDeprecatedInterfaceClass', true);
+        class_exists('Test\\'.NonDeprecatedInterfaceClass::class, true);

        error_reporting($e);
        restore_error_handler();
@@ -205,7 +199,7 @@ class DebugClassLoaderTest extends TestCase
        require __DIR__.'/Fixtures/FinalClasses.php';

        $i = 1;
-        while(class_exists($finalClass = __NAMESPACE__.'\\Fixtures\\FinalClass'.$i++, false)) {
+        while (class_exists($finalClass = Fixtures\FinalClass::class.$i++, false)) {
            spl_autoload_call($finalClass);
            class_exists('Test\\'.__NAMESPACE__.'\\Extends'.substr($finalClass, strrpos($finalClass, '\\') + 1), true);
        }
@@ -231,7 +225,7 @@ class DebugClassLoaderTest extends TestCase
        set_error_handler(function ($type, $msg) use (&$deprecations) { $deprecations[] = $msg; });
        $e = error_reporting(E_USER_DEPRECATED);

-        class_exists(__NAMESPACE__.'\\Fixtures\\ExtendedFinalMethod', true);
+        class_exists(Fixtures\ExtendedFinalMethod::class, true);

        error_reporting($e);
        restore_error_handler();
@@ -250,7 +244,7 @@ class DebugClassLoaderTest extends TestCase
        $e = error_reporting(0);
        trigger_error('', E_USER_NOTICE);

-        class_exists('Test\\'.__NAMESPACE__.'\\ExtendsAnnotatedClass', true);
+        class_exists('Test\\'.ExtendsAnnotatedClass::class, true);

        error_reporting($e);
        restore_error_handler();
@@ -267,7 +261,7 @@ class DebugClassLoaderTest extends TestCase
        set_error_handler(function ($type, $msg) use (&$deprecations) { $deprecations[] = $msg; });
        $e = error_reporting(E_USER_DEPRECATED);

-        class_exists('Test\\'.__NAMESPACE__.'\\ExtendsInternals', true);
+        class_exists('Test\\'.ExtendsInternals::class, true);

        error_reporting($e);
        restore_error_handler();
@@ -280,19 +274,87 @@ class DebugClassLoaderTest extends TestCase
        ]);
    }

+    public function testExtendedMethodDefinesNewParameters()
+    {
+        $deprecations = [];
+        set_error_handler(function ($type, $msg) use (&$deprecations) { $deprecations[] = $msg; });
+        $e = error_reporting(E_USER_DEPRECATED);
+
+        class_exists(Fixtures\SubClassWithAnnotatedParameters::class, true);
+
+        error_reporting($e);
+        restore_error_handler();
+
+        $this->assertSame([
+            'The "Symfony\Component\Debug\Tests\Fixtures\SubClassWithAnnotatedParameters::quzMethod()" method will require a new "Quz $quz" argument in the next major version of its parent class "Symfony\Component\Debug\Tests\Fixtures\ClassWithAnnotatedParameters", not defining it is deprecated.',
+            'The "Symfony\Component\Debug\Tests\Fixtures\SubClassWithAnnotatedParameters::whereAmI()" method will require a new "bool $matrix" argument in the next major version of its parent class "Symfony\Component\Debug\Tests\Fixtures\InterfaceWithAnnotatedParameters", not defining it is deprecated.',
+            'The "Symfony\Component\Debug\Tests\Fixtures\SubClassWithAnnotatedParameters::iAmHere()" method will require a new "$noType" argument in the next major version of its parent class "Symfony\Component\Debug\Tests\Fixtures\InterfaceWithAnnotatedParameters", not defining it is deprecated.',
+            'The "Symfony\Component\Debug\Tests\Fixtures\SubClassWithAnnotatedParameters::iAmHere()" method will require a new "callable(\Throwable|null $reason, mixed $value) $callback" argument in the next major version of its parent class "Symfony\Component\Debug\Tests\Fixtures\InterfaceWithAnnotatedParameters", not defining it is deprecated.',
+            'The "Symfony\Component\Debug\Tests\Fixtures\SubClassWithAnnotatedParameters::iAmHere()" method will require a new "string $param" argument in the next major version of its parent class "Symfony\Component\Debug\Tests\Fixtures\InterfaceWithAnnotatedParameters", not defining it is deprecated.',
+            'The "Symfony\Component\Debug\Tests\Fixtures\SubClassWithAnnotatedParameters::iAmHere()" method will require a new "callable  ($a,  $b) $anotherOne" argument in the next major version of its parent class "Symfony\Component\Debug\Tests\Fixtures\InterfaceWithAnnotatedParameters", not defining it is deprecated.',
+            'The "Symfony\Component\Debug\Tests\Fixtures\SubClassWithAnnotatedParameters::iAmHere()" method will require a new "Type$WithDollarIsStillAType $ccc" argument in the next major version of its parent class "Symfony\Component\Debug\Tests\Fixtures\InterfaceWithAnnotatedParameters", not defining it is deprecated.',
+            'The "Symfony\Component\Debug\Tests\Fixtures\SubClassWithAnnotatedParameters::isSymfony()" method will require a new "true $yes" argument in the next major version of its parent class "Symfony\Component\Debug\Tests\Fixtures\ClassWithAnnotatedParameters", not defining it is deprecated.',
+        ], $deprecations);
+    }
+
    public function testUseTraitWithInternalMethod()
    {
        $deprecations = [];
        set_error_handler(function ($type, $msg) use (&$deprecations) { $deprecations[] = $msg; });
        $e = error_reporting(E_USER_DEPRECATED);

-        class_exists('Test\\'.__NAMESPACE__.'\\UseTraitWithInternalMethod', true);
+        class_exists('Test\\'.UseTraitWithInternalMethod::class, true);

        error_reporting($e);
        restore_error_handler();

        $this->assertSame([], $deprecations);
    }
+
+    public function testVirtualUse()
+    {
+        $deprecations = [];
+        set_error_handler(function ($type, $msg) use (&$deprecations) { $deprecations[] = $msg; });
+        $e = error_reporting(E_USER_DEPRECATED);
+
+        class_exists('Test\\'.ExtendsVirtual::class, true);
+
+        error_reporting($e);
+        restore_error_handler();
+
+        $this->assertSame([
+            'Class "Test\Symfony\Component\Debug\Tests\ExtendsVirtualParent" should implement method "Symfony\Component\Debug\Tests\Fixtures\VirtualInterface::sameLineInterfaceMethodNoBraces()".',
+            'Class "Test\Symfony\Component\Debug\Tests\ExtendsVirtualParent" should implement method "Symfony\Component\Debug\Tests\Fixtures\VirtualInterface::newLineInterfaceMethod()": Some description!',
+            'Class "Test\Symfony\Component\Debug\Tests\ExtendsVirtualParent" should implement method "Symfony\Component\Debug\Tests\Fixtures\VirtualInterface::newLineInterfaceMethodNoBraces()": Description.',
+            'Class "Test\Symfony\Component\Debug\Tests\ExtendsVirtualParent" should implement method "Symfony\Component\Debug\Tests\Fixtures\VirtualInterface::invalidInterfaceMethod()".',
+            'Class "Test\Symfony\Component\Debug\Tests\ExtendsVirtualParent" should implement method "Symfony\Component\Debug\Tests\Fixtures\VirtualInterface::invalidInterfaceMethodNoBraces()".',
+            'Class "Test\Symfony\Component\Debug\Tests\ExtendsVirtualParent" should implement method "Symfony\Component\Debug\Tests\Fixtures\VirtualInterface::complexInterfaceMethod($arg, ...$args)".',
+            'Class "Test\Symfony\Component\Debug\Tests\ExtendsVirtualParent" should implement method "Symfony\Component\Debug\Tests\Fixtures\VirtualInterface::complexInterfaceMethodTyped($arg, int ...$args)": Description ...',
+            'Class "Test\Symfony\Component\Debug\Tests\ExtendsVirtualParent" should implement method "static Symfony\Component\Debug\Tests\Fixtures\VirtualInterface::staticMethodNoBraces()".',
+            'Class "Test\Symfony\Component\Debug\Tests\ExtendsVirtualParent" should implement method "static Symfony\Component\Debug\Tests\Fixtures\VirtualInterface::staticMethodTyped(int $arg)": Description.',
+            'Class "Test\Symfony\Component\Debug\Tests\ExtendsVirtualParent" should implement method "static Symfony\Component\Debug\Tests\Fixtures\VirtualInterface::staticMethodTypedNoBraces()".',
+            'Class "Test\Symfony\Component\Debug\Tests\ExtendsVirtual" should implement method "Symfony\Component\Debug\Tests\Fixtures\VirtualSubInterface::subInterfaceMethod()".',
+        ], $deprecations);
+    }
+
+    public function testVirtualUseWithMagicCall()
+    {
+        $deprecations = [];
+        set_error_handler(function ($type, $msg) use (&$deprecations) { $deprecations[] = $msg; });
+        $e = error_reporting(E_USER_DEPRECATED);
+
+        class_exists('Test\\'.ExtendsVirtualMagicCall::class, true);
+
+        error_reporting($e);
+        restore_error_handler();
+
+        $this->assertSame([], $deprecations);
+    }
+
+    public function testEvaluatedCode()
+    {
+        $this->assertTrue(class_exists(Fixtures\DefinitionInEvaluatedCode::class, true));
+    }
 }

 class ClassLoader
@@ -308,47 +370,75 @@ class ClassLoader

    public function findFile($class)
    {
-        $fixtureDir = __DIR__.DIRECTORY_SEPARATOR.'Fixtures'.DIRECTORY_SEPARATOR;
+        $fixtureDir = __DIR__.\DIRECTORY_SEPARATOR.'Fixtures'.\DIRECTORY_SEPARATOR;

-        if (__NAMESPACE__.'\TestingUnsilencing' === $class) {
+        if (TestingUnsilencing::class === $class) {
            eval('-- parse error --');
-        } elseif (__NAMESPACE__.'\TestingStacking' === $class) {
+        } elseif (TestingStacking::class === $class) {
            eval('namespace '.__NAMESPACE__.'; class TestingStacking { function foo() {} }');
-        } elseif (__NAMESPACE__.'\TestingCaseMismatch' === $class) {
+        } elseif (TestingCaseMismatch::class === $class) {
            eval('namespace '.__NAMESPACE__.'; class TestingCaseMisMatch {}');
        } elseif (__NAMESPACE__.'\Fixtures\Psr4CaseMismatch' === $class) {
-            return $fixtureDir.'psr4'.DIRECTORY_SEPARATOR.'Psr4CaseMismatch.php';
+            return $fixtureDir.'psr4'.\DIRECTORY_SEPARATOR.'Psr4CaseMismatch.php';
        } elseif (__NAMESPACE__.'\Fixtures\NotPSR0' === $class) {
            return $fixtureDir.'reallyNotPsr0.php';
        } elseif (__NAMESPACE__.'\Fixtures\NotPSR0bis' === $class) {
            return $fixtureDir.'notPsr0Bis.php';
        } elseif ('Symfony\Bridge\Debug\Tests\Fixtures\ExtendsDeprecatedParent' === $class) {
            eval('namespace Symfony\Bridge\Debug\Tests\Fixtures; class ExtendsDeprecatedParent extends \\'.__NAMESPACE__.'\Fixtures\DeprecatedClass {}');
-        } elseif ('Test\\'.__NAMESPACE__.'\DeprecatedParentClass' === $class) {
+        } elseif ('Test\\'.DeprecatedParentClass::class === $class) {
            eval('namespace Test\\'.__NAMESPACE__.'; class DeprecatedParentClass extends \\'.__NAMESPACE__.'\Fixtures\DeprecatedClass {}');
-        } elseif ('Test\\'.__NAMESPACE__.'\DeprecatedInterfaceClass' === $class) {
+        } elseif ('Test\\'.DeprecatedInterfaceClass::class === $class) {
            eval('namespace Test\\'.__NAMESPACE__.'; class DeprecatedInterfaceClass implements \\'.__NAMESPACE__.'\Fixtures\DeprecatedInterface {}');
-        } elseif ('Test\\'.__NAMESPACE__.'\NonDeprecatedInterfaceClass' === $class) {
+        } elseif ('Test\\'.NonDeprecatedInterfaceClass::class === $class) {
            eval('namespace Test\\'.__NAMESPACE__.'; class NonDeprecatedInterfaceClass implements \\'.__NAMESPACE__.'\Fixtures\NonDeprecatedInterface {}');
-        } elseif ('Test\\'.__NAMESPACE__.'\Float' === $class) {
+        } elseif ('Test\\'.Float::class === $class) {
            eval('namespace Test\\'.__NAMESPACE__.'; class Float {}');
-        } elseif (0 === strpos($class, 'Test\\'.__NAMESPACE__.'\ExtendsFinalClass')) {
+        } elseif (0 === strpos($class, 'Test\\'.ExtendsFinalClass::class)) {
            $classShortName = substr($class, strrpos($class, '\\') + 1);
            eval('namespace Test\\'.__NAMESPACE__.'; class '.$classShortName.' extends \\'.__NAMESPACE__.'\Fixtures\\'.substr($classShortName, 7).' {}');
-        } elseif ('Test\\'.__NAMESPACE__.'\ExtendsAnnotatedClass' === $class) {
+        } elseif ('Test\\'.ExtendsAnnotatedClass::class === $class) {
            eval('namespace Test\\'.__NAMESPACE__.'; class ExtendsAnnotatedClass extends \\'.__NAMESPACE__.'\Fixtures\AnnotatedClass {
                public function deprecatedMethod() { }
            }');
-        } elseif ('Test\\'.__NAMESPACE__.'\ExtendsInternals' === $class) {
+        } elseif ('Test\\'.ExtendsInternals::class === $class) {
            eval('namespace Test\\'.__NAMESPACE__.'; class ExtendsInternals extends ExtendsInternalsParent {
                use \\'.__NAMESPACE__.'\Fixtures\InternalTrait;

                public function internalMethod() { }
            }');
-        } elseif ('Test\\'.__NAMESPACE__.'\ExtendsInternalsParent' === $class) {
+        } elseif ('Test\\'.ExtendsInternalsParent::class === $class) {
            eval('namespace Test\\'.__NAMESPACE__.'; class ExtendsInternalsParent extends \\'.__NAMESPACE__.'\Fixtures\InternalClass implements \\'.__NAMESPACE__.'\Fixtures\InternalInterface { }');
-        } elseif ('Test\\'.__NAMESPACE__.'\UseTraitWithInternalMethod' === $class) {
+        } elseif ('Test\\'.UseTraitWithInternalMethod::class === $class) {
            eval('namespace Test\\'.__NAMESPACE__.'; class UseTraitWithInternalMethod { use \\'.__NAMESPACE__.'\Fixtures\TraitWithInternalMethod; }');
+        } elseif ('Test\\'.ExtendsVirtual::class === $class) {
+            eval('namespace Test\\'.__NAMESPACE__.'; class ExtendsVirtual extends ExtendsVirtualParent implements \\'.__NAMESPACE__.'\Fixtures\VirtualSubInterface {
+                public function ownClassMethod() { }
+                public function classMethod() { }
+                public function sameLineInterfaceMethodNoBraces() { }
+            }');
+        } elseif ('Test\\'.ExtendsVirtualParent::class === $class) {
+            eval('namespace Test\\'.__NAMESPACE__.'; class ExtendsVirtualParent extends ExtendsVirtualAbstract {
+                public function ownParentMethod() { }
+                public function traitMethod() { }
+                public function sameLineInterfaceMethod() { }
+                public function staticMethodNoBraces() { } // should be static
+            }');
+        } elseif ('Test\\'.ExtendsVirtualAbstract::class === $class) {
+            eval('namespace Test\\'.__NAMESPACE__.'; abstract class ExtendsVirtualAbstract extends ExtendsVirtualAbstractBase {
+                public static function staticMethod() { }
+                public function ownAbstractMethod() { }
+                public function interfaceMethod() { }
+            }');
+        } elseif ('Test\\'.ExtendsVirtualAbstractBase::class === $class) {
+            eval('namespace Test\\'.__NAMESPACE__.'; abstract class ExtendsVirtualAbstractBase extends \\'.__NAMESPACE__.'\Fixtures\VirtualClass implements \\'.__NAMESPACE__.'\Fixtures\VirtualInterface {
+                public function ownAbstractBaseMethod() { }
+            }');
+        } elseif ('Test\\'.ExtendsVirtualMagicCall::class === $class) {
+            eval('namespace Test\\'.__NAMESPACE__.'; class ExtendsVirtualMagicCall extends \\'.__NAMESPACE__.'\Fixtures\VirtualClassMagicCall implements \\'.__NAMESPACE__.'\Fixtures\VirtualInterface {
+            }');
        }
+
+        return null;
    }
 }
--- a/Tests/ErrorHandlerTest.php
+++ b/Tests/ErrorHandlerTest.php
@@ -12,12 +12,12 @@
 namespace Symfony\Component\Debug\Tests;

 use PHPUnit\Framework\TestCase;
-use Psr\Log\LoggerInterface;
 use Psr\Log\LogLevel;
 use Psr\Log\NullLogger;
 use Symfony\Component\Debug\BufferingLogger;
 use Symfony\Component\Debug\ErrorHandler;
 use Symfony\Component\Debug\Exception\SilencedErrorContext;
+use Symfony\Component\Debug\Tests\Fixtures\ErrorHandlerThatUsesThePreviousOne;
 use Symfony\Component\Debug\Tests\Fixtures\LoggerThatSetAnErrorHandler;

 /**
@@ -70,8 +70,8 @@ class ErrorHandlerTest extends TestCase

    public function testErrorGetLast()
    {
-        $handler = ErrorHandler::register();
        $logger = $this->getMockBuilder('Psr\Log\LoggerInterface')->getMock();
+        $handler = ErrorHandler::register();
        $handler->setDefaultLogger($logger);
        $handler->screamAt(E_ALL);

@@ -143,9 +143,8 @@ class ErrorHandlerTest extends TestCase
    public function testDefaultLogger()
    {
        try {
-            $handler = ErrorHandler::register();
-
            $logger = $this->getMockBuilder('Psr\Log\LoggerInterface')->getMock();
+            $handler = ErrorHandler::register();

            $handler->setDefaultLogger($logger, E_NOTICE);
            $handler->setDefaultLogger($logger, [E_USER_NOTICE => LogLevel::CRITICAL]);
@@ -234,7 +233,7 @@ class ErrorHandlerTest extends TestCase
            $logger
                ->expects($this->once())
                ->method('log')
-                ->will($this->returnCallback($warnArgCheck))
+                ->willReturnCallback($warnArgCheck)
            ;

            $handler = ErrorHandler::register();
@@ -262,7 +261,7 @@ class ErrorHandlerTest extends TestCase
            $logger
                ->expects($this->once())
                ->method('log')
-                ->will($this->returnCallback($logArgCheck))
+                ->willReturnCallback($logArgCheck)
            ;

            $handler = ErrorHandler::register();
@@ -284,6 +283,10 @@ class ErrorHandlerTest extends TestCase

    public function testHandleUserError()
    {
+        if (\PHP_VERSION_ID >= 70400) {
+            $this->markTestSkipped('PHP 7.4 allows __toString to throw exceptions');
+        }
+
        try {
            $handler = ErrorHandler::register();
            $handler->throwAt(0, true);
@@ -318,7 +321,7 @@ class ErrorHandlerTest extends TestCase
        $logger
            ->expects($this->once())
            ->method('log')
-            ->will($this->returnCallback($logArgCheck))
+            ->willReturnCallback($logArgCheck)
        ;

        $handler = new ErrorHandler();
@@ -331,12 +334,11 @@ class ErrorHandlerTest extends TestCase
    public function testHandleException()
    {
        try {
+            $logger = $this->getMockBuilder('Psr\Log\LoggerInterface')->getMock();
            $handler = ErrorHandler::register();

            $exception = new \Exception('foo');

-            $logger = $this->getMockBuilder('Psr\Log\LoggerInterface')->getMock();
-
            $logArgCheck = function ($level, $message, $context) {
                $this->assertSame('Uncaught Exception: foo', $message);
                $this->assertArrayHasKey('exception', $context);
@@ -346,7 +348,7 @@ class ErrorHandlerTest extends TestCase
            $logger
                ->expects($this->exactly(2))
                ->method('log')
-                ->will($this->returnCallback($logArgCheck))
+                ->willReturnCallback($logArgCheck)
            ;

            $handler->setDefaultLogger($logger, E_ERROR);
@@ -442,6 +444,7 @@ class ErrorHandlerTest extends TestCase
    public function testHandleFatalError()
    {
        try {
+            $logger = $this->getMockBuilder('Psr\Log\LoggerInterface')->getMock();
            $handler = ErrorHandler::register();

            $error = [
@@ -451,8 +454,6 @@ class ErrorHandlerTest extends TestCase
                'line' => 123,
            ];

-            $logger = $this->getMockBuilder('Psr\Log\LoggerInterface')->getMock();
-
            $logArgCheck = function ($level, $message, $context) {
                $this->assertEquals('Fatal Parse Error: foo', $message);
                $this->assertArrayHasKey('exception', $context);
@@ -462,7 +463,7 @@ class ErrorHandlerTest extends TestCase
            $logger
                ->expects($this->once())
                ->method('log')
-                ->will($this->returnCallback($logArgCheck))
+                ->willReturnCallback($logArgCheck)
            ;

            $handler->setDefaultLogger($logger, E_PARSE);
@@ -481,7 +482,7 @@ class ErrorHandlerTest extends TestCase

    public function testHandleErrorException()
    {
-        $exception = new \Error("Class 'Foo' not found");
+        $exception = new \Error("Class 'IReallyReallyDoNotExistAnywhereInTheRepositoryISwear' not found");

        $handler = new ErrorHandler();
        $handler->setExceptionHandler(function () use (&$args) {
@@ -491,14 +492,12 @@ class ErrorHandlerTest extends TestCase
        $handler->handleException($exception);

        $this->assertInstanceOf('Symfony\Component\Debug\Exception\ClassNotFoundException', $args[0]);
-        $this->assertStringStartsWith("Attempted to load class \"Foo\" from the global namespace.\nDid you forget a \"use\" statement", $args[0]->getMessage());
+        $this->assertStringStartsWith("Attempted to load class \"IReallyReallyDoNotExistAnywhereInTheRepositoryISwear\" from the global namespace.\nDid you forget a \"use\" statement", $args[0]->getMessage());
    }

-    /**
-     * @expectedException \Exception
-     */
    public function testCustomExceptionHandler()
    {
+        $this->expectException('Exception');
        $handler = new ErrorHandler();
        $handler->setExceptionHandler(function ($e) use ($handler) {
            $handler->handleException($e);
@@ -508,26 +507,40 @@ class ErrorHandlerTest extends TestCase
    }

    /**
-     * @dataProvider errorHandlerIsNotLostWhenLoggingProvider
+     * @dataProvider errorHandlerWhenLoggingProvider
     */
-    public function testErrorHandlerIsNotLostWhenLogging($customErrorHandlerHasBeenPreviouslyDefined, LoggerInterface $logger)
+    public function testErrorHandlerWhenLogging($previousHandlerWasDefined, $loggerSetsAnotherHandler, $nextHandlerIsDefined)
    {
        try {
-            if ($customErrorHandlerHasBeenPreviouslyDefined) {
+            if ($previousHandlerWasDefined) {
                set_error_handler('count');
            }

+            $logger = $loggerSetsAnotherHandler ? new LoggerThatSetAnErrorHandler() : new NullLogger();
+
            $handler = ErrorHandler::register();
            $handler->setDefaultLogger($logger);

+            if ($nextHandlerIsDefined) {
+                $handler = ErrorHandlerThatUsesThePreviousOne::register();
+            }
+
            @trigger_error('foo', E_USER_DEPRECATED);
            @trigger_error('bar', E_USER_DEPRECATED);

            $this->assertSame([$handler, 'handleError'], set_error_handler('var_dump'));

+            if ($logger instanceof LoggerThatSetAnErrorHandler) {
+                $this->assertCount(2, $logger->cleanLogs());
+            }
+
            restore_error_handler();

-            if ($customErrorHandlerHasBeenPreviouslyDefined) {
+            if ($previousHandlerWasDefined) {
+                restore_error_handler();
+            }
+
+            if ($nextHandlerIsDefined) {
                restore_error_handler();
            }
        } finally {
@@ -536,13 +549,14 @@ class ErrorHandlerTest extends TestCase
        }
    }

-    public function errorHandlerIsNotLostWhenLoggingProvider()
+    public function errorHandlerWhenLoggingProvider()
    {
-        return [
-            [false, new NullLogger()],
-            [true, new NullLogger()],
-            [false, new LoggerThatSetAnErrorHandler()],
-            [true, new LoggerThatSetAnErrorHandler()],
-        ];
+        foreach ([false, true] as $previousHandlerWasDefined) {
+            foreach ([false, true] as $loggerSetsAnotherHandler) {
+                foreach ([false, true] as $nextHandlerIsDefined) {
+                    yield [$previousHandlerWasDefined, $loggerSetsAnotherHandler, $nextHandlerIsDefined];
+                }
+            }
+        }
    }
 }
--- a/Tests/Exception/FlattenExceptionTest.php
+++ b/Tests/Exception/FlattenExceptionTest.php
@@ -237,6 +237,10 @@ class FlattenExceptionTest extends TestCase

    public function testArguments()
    {
+        if (\PHP_VERSION_ID >= 70400) {
+            $this->markTestSkipped('PHP 7.4 removes arguments from exception traces.');
+        }
+
        $dh = opendir(__DIR__);
        $fh = tmpfile();

@@ -294,22 +298,30 @@ 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()
    {
+        if (\PHP_VERSION_ID >= 70400) {
+            $this->markTestSkipped('PHP 7.4 removes arguments from exception traces.');
+        }
+
        $a = null;
        $a = ['foo', [2, &$a]];
        $exception = $this->createException($a);

        $flattened = FlattenException::create($exception);
        $trace = $flattened->getTrace();
-        $this->assertContains('*DEEP NESTED ARRAY*', serialize($trace));
+        $this->assertStringContainsString('*DEEP NESTED ARRAY*', serialize($trace));
    }

    public function testTooBigArray()
    {
+        if (\PHP_VERSION_ID >= 70400) {
+            $this->markTestSkipped('PHP 7.4 removes arguments from exception traces.');
+        }
+
        $a = [];
        for ($i = 0; $i < 20; ++$i) {
            for ($j = 0; $j < 50; ++$j) {
@@ -329,8 +341,56 @@ class FlattenExceptionTest extends TestCase

        $serializeTrace = serialize($trace);

-        $this->assertContains('*SKIPPED over 10000 entries*', $serializeTrace);
-        $this->assertNotContains('*value1*', $serializeTrace);
+        $this->assertStringContainsString('*SKIPPED over 10000 entries*', $serializeTrace);
+        $this->assertStringNotContainsString('*value1*', $serializeTrace);
+    }
+
+    public function testAnonymousClass()
+    {
+        $flattened = FlattenException::create(new class() extends \RuntimeException {
+        });
+
+        $this->assertSame('RuntimeException@anonymous', $flattened->getClass());
+
+        $flattened = FlattenException::create(new \Exception(sprintf('Class "%s" blah.', \get_class(new class() extends \RuntimeException {
+        }))));
+
+        $this->assertSame('Class "RuntimeException@anonymous" blah.', $flattened->getMessage());
+    }
+
+    public function testToStringEmptyMessage()
+    {
+        $exception = new \RuntimeException();
+
+        $flattened = FlattenException::create($exception);
+
+        $this->assertSame($exception->getTraceAsString(), $flattened->getTraceAsString());
+        $this->assertSame($exception->__toString(), $flattened->getAsString());
+    }
+
+    public function testToString()
+    {
+        $test = function ($a, $b, $c, $d) {
+            return new \RuntimeException('This is a test message');
+        };
+
+        $exception = $test('foo123', 1, null, 1.5);
+
+        $flattened = FlattenException::create($exception);
+
+        $this->assertSame($exception->getTraceAsString(), $flattened->getTraceAsString());
+        $this->assertSame($exception->__toString(), $flattened->getAsString());
+    }
+
+    public function testToStringParent()
+    {
+        $exception = new \LogicException('This is message 1');
+        $exception = new \RuntimeException('This is messsage 2', 500, $exception);
+
+        $flattened = FlattenException::create($exception);
+
+        $this->assertSame($exception->getTraceAsString(), $flattened->getTraceAsString());
+        $this->assertSame($exception->__toString(), $flattened->getAsString());
    }

    private function createException($foo)
--- a/Tests/ExceptionHandlerTest.php
+++ b/Tests/ExceptionHandlerTest.php
@@ -21,12 +21,12 @@ require_once __DIR__.'/HeaderMock.php';

 class ExceptionHandlerTest extends TestCase
 {
-    protected function setUp()
+    protected function setUp(): void
    {
        testHeader();
    }

-    protected function tearDown()
+    protected function tearDown(): void
    {
        testHeader();
    }
@@ -39,8 +39,8 @@ class ExceptionHandlerTest extends TestCase
        $handler->sendPhpResponse(new \RuntimeException('Foo'));
        $response = ob_get_clean();

-        $this->assertContains('Whoops, looks like something went wrong.', $response);
-        $this->assertNotContains('<div class="trace trace-as-html">', $response);
+        $this->assertStringContainsString('Whoops, looks like something went wrong.', $response);
+        $this->assertStringNotContainsString('<div class="trace trace-as-html">', $response);

        $handler = new ExceptionHandler(true);

@@ -48,8 +48,17 @@ class ExceptionHandlerTest extends TestCase
        $handler->sendPhpResponse(new \RuntimeException('Foo'));
        $response = ob_get_clean();

-        $this->assertContains('Whoops, looks like something went wrong.', $response);
-        $this->assertContains('<div class="trace trace-as-html">', $response);
+        $this->assertStringContainsString('<h1 class="break-long-words exception-message">Foo</h1>', $response);
+        $this->assertStringContainsString('<div class="trace trace-as-html">', $response);
+
+        // taken from https://www.owasp.org/index.php/Cross-site_Scripting_(XSS)
+        $htmlWithXss = '<body onload=alert(\'test1\')> <b onmouseover=alert(\'Wufff!\')>click me!</b> <img src="j&#X41vascript:alert(\'test2\')"> <meta http-equiv="refresh"
+content="0;url=data:text/html;base64,PHNjcmlwdD5hbGVydCgndGVzdDMnKTwvc2NyaXB0Pg">';
+        ob_start();
+        $handler->sendPhpResponse(new \RuntimeException($htmlWithXss));
+        $response = ob_get_clean();
+
+        $this->assertStringContainsString(sprintf('<h1 class="break-long-words exception-message">%s</h1>', htmlspecialchars($htmlWithXss, ENT_COMPAT | ENT_SUBSTITUTE, 'UTF-8')), $response);
    }

    public function testStatusCode()
@@ -60,7 +69,7 @@ class ExceptionHandlerTest extends TestCase
        $handler->sendPhpResponse(new NotFoundHttpException('Foo'));
        $response = ob_get_clean();

-        $this->assertContains('Sorry, the page you are looking for could not be found.', $response);
+        $this->assertStringContainsString('Sorry, the page you are looking for could not be found.', $response);

        $expectedHeaders = [
            ['HTTP/1.0 404', true, null],
@@ -76,7 +85,7 @@ class ExceptionHandlerTest extends TestCase

        ob_start();
        $handler->sendPhpResponse(new MethodNotAllowedHttpException(['POST']));
-        $response = ob_get_clean();
+        ob_get_clean();

        $expectedHeaders = [
            ['HTTP/1.0 405', true, null],
@@ -99,35 +108,65 @@ class ExceptionHandlerTest extends TestCase

    public function testHandle()
    {
-        $exception = new \Exception('foo');
+        $handler = new ExceptionHandler(true);
+        ob_start();

-        $handler = $this->getMockBuilder('Symfony\Component\Debug\ExceptionHandler')->setMethods(['sendPhpResponse'])->getMock();
-        $handler
-            ->expects($this->exactly(2))
-            ->method('sendPhpResponse');
+        $handler->handle(new \Exception('foo'));

-        $handler->handle($exception);
+        $this->assertThatTheExceptionWasOutput(ob_get_clean(), \Exception::class, 'Exception', 'foo');
+    }

-        $handler->setHandler(function ($e) use ($exception) {
-            $this->assertSame($exception, $e);
+    public function testHandleWithACustomHandlerThatOutputsSomething()
+    {
+        $handler = new ExceptionHandler(true);
+        ob_start();
+        $handler->setHandler(function () {
+            echo 'ccc';
        });

-        $handler->handle($exception);
+        $handler->handle(new \Exception());
+        ob_end_flush(); // Necessary because of this PHP bug : https://bugs.php.net/76563
+        $this->assertSame('ccc', ob_get_clean());
+    }
+
+    public function testHandleWithACustomHandlerThatOutputsNothing()
+    {
+        $handler = new ExceptionHandler(true);
+        $handler->setHandler(function () {});
+
+        $handler->handle(new \Exception('ccc'));
+
+        $this->assertThatTheExceptionWasOutput(ob_get_clean(), \Exception::class, 'Exception', 'ccc');
+    }
+
+    public function testHandleWithACustomHandlerThatFails()
+    {
+        $handler = new ExceptionHandler(true);
+        $handler->setHandler(function () {
+            throw new \RuntimeException();
+        });
+
+        $handler->handle(new \Exception('ccc'));
+
+        $this->assertThatTheExceptionWasOutput(ob_get_clean(), \Exception::class, 'Exception', 'ccc');
    }

    public function testHandleOutOfMemoryException()
    {
-        $exception = new OutOfMemoryException('foo', 0, E_ERROR, __FILE__, __LINE__);
-
-        $handler = $this->getMockBuilder('Symfony\Component\Debug\ExceptionHandler')->setMethods(['sendPhpResponse'])->getMock();
-        $handler
-            ->expects($this->once())
-            ->method('sendPhpResponse');
-
-        $handler->setHandler(function ($e) {
+        $handler = new ExceptionHandler(true);
+        ob_start();
+        $handler->setHandler(function () {
            $this->fail('OutOfMemoryException should bypass the handler');
        });

-        $handler->handle($exception);
+        $handler->handle(new OutOfMemoryException('foo', 0, E_ERROR, __FILE__, __LINE__));
+
+        $this->assertThatTheExceptionWasOutput(ob_get_clean(), OutOfMemoryException::class, 'OutOfMemoryException', 'foo');
+    }
+
+    private function assertThatTheExceptionWasOutput($content, $expectedClass, $expectedTitle, $expectedMessage)
+    {
+        $this->assertStringContainsString(sprintf('<span class="exception_title"><abbr title="%s">%s</abbr></span>', $expectedClass, $expectedTitle), $content);
+        $this->assertStringContainsString(sprintf('<p class="break-long-words trace-message">%s</p>', $expectedMessage), $content);
    }
 }
--- a/Tests/FatalErrorHandler/ClassNotFoundFatalErrorHandlerTest.php
+++ b/Tests/FatalErrorHandler/ClassNotFoundFatalErrorHandlerTest.php
@@ -19,7 +19,7 @@ use Symfony\Component\Debug\FatalErrorHandler\ClassNotFoundFatalErrorHandler;

 class ClassNotFoundFatalErrorHandlerTest extends TestCase
 {
-    public static function setUpBeforeClass()
+    public static function setUpBeforeClass(): void
    {
        foreach (spl_autoload_functions() as $function) {
            if (!\is_array($function)) {
@@ -29,10 +29,14 @@ class ClassNotFoundFatalErrorHandlerTest extends TestCase
            // get class loaders wrapped by DebugClassLoader
            if ($function[0] instanceof DebugClassLoader) {
                $function = $function[0]->getClassLoader();
+
+                if (!\is_array($function)) {
+                    continue;
+                }
            }

            if ($function[0] instanceof ComposerClassLoader) {
-                $function[0]->add('Symfony_Component_Debug_Tests_Fixtures', \dirname(\dirname(\dirname(\dirname(\dirname(__DIR__))))));
+                $function[0]->add('Symfony_Component_Debug_Tests_Fixtures', \dirname(__DIR__, 5));
                break;
            }
        }
@@ -61,7 +65,7 @@ class ClassNotFoundFatalErrorHandlerTest extends TestCase
        }

        $this->assertInstanceOf('Symfony\Component\Debug\Exception\ClassNotFoundException', $exception);
-        $this->assertSame($translatedMessage, $exception->getMessage());
+        $this->assertRegExp($translatedMessage, $exception->getMessage());
        $this->assertSame($error['type'], $exception->getSeverity());
        $this->assertSame($error['file'], $exception->getFile());
        $this->assertSame($error['line'], $exception->getLine());
@@ -71,6 +75,7 @@ class ClassNotFoundFatalErrorHandlerTest extends TestCase
    {
        $autoloader = new ComposerClassLoader();
        $autoloader->add('Symfony\Component\Debug\Exception\\', realpath(__DIR__.'/../../Exception'));
+        $autoloader->add('Symfony_Component_Debug_Tests_Fixtures', realpath(__DIR__.'/../../Tests/Fixtures'));

        $debugClassLoader = new DebugClassLoader([$autoloader, 'loadClass']);

@@ -82,7 +87,7 @@ class ClassNotFoundFatalErrorHandlerTest extends TestCase
                    'file' => 'foo.php',
                    'message' => 'Class \'WhizBangFactory\' not found',
                ],
-                "Attempted to load class \"WhizBangFactory\" from the global namespace.\nDid you forget a \"use\" statement?",
+                "/^Attempted to load class \"WhizBangFactory\" from the global namespace.\nDid you forget a \"use\" statement\?$/",
            ],
            [
                [
@@ -91,7 +96,7 @@ class ClassNotFoundFatalErrorHandlerTest extends TestCase
                    'file' => 'foo.php',
                    'message' => 'Class \'Foo\\Bar\\WhizBangFactory\' not found',
                ],
-                "Attempted to load class \"WhizBangFactory\" from namespace \"Foo\\Bar\".\nDid you forget a \"use\" statement for another namespace?",
+                "/^Attempted to load class \"WhizBangFactory\" from namespace \"Foo\\\\Bar\".\nDid you forget a \"use\" statement for another namespace\?$/",
            ],
            [
                [
@@ -100,7 +105,8 @@ class ClassNotFoundFatalErrorHandlerTest extends TestCase
                    'file' => 'foo.php',
                    'message' => 'Class \'UndefinedFunctionException\' not found',
                ],
-                "Attempted to load class \"UndefinedFunctionException\" from the global namespace.\nDid you forget a \"use\" statement for \"Symfony\Component\Debug\Exception\UndefinedFunctionException\"?",
+                "/^Attempted to load class \"UndefinedFunctionException\" from the global namespace.\nDid you forget a \"use\" statement for .*\"Symfony\\\\Component\\\\Debug\\\\Exception\\\\UndefinedFunctionException\"\?$/",
+                [$debugClassLoader, 'loadClass'],
            ],
            [
                [
@@ -109,35 +115,7 @@ class ClassNotFoundFatalErrorHandlerTest extends TestCase
                    'file' => 'foo.php',
                    'message' => 'Class \'PEARClass\' not found',
                ],
-                "Attempted to load class \"PEARClass\" from the global namespace.\nDid you forget a \"use\" statement for \"Symfony_Component_Debug_Tests_Fixtures_PEARClass\"?",
-            ],
-            [
-                [
-                    'type' => 1,
-                    'line' => 12,
-                    'file' => 'foo.php',
-                    'message' => 'Class \'Foo\\Bar\\UndefinedFunctionException\' not found',
-                ],
-                "Attempted to load class \"UndefinedFunctionException\" from namespace \"Foo\Bar\".\nDid you forget a \"use\" statement for \"Symfony\Component\Debug\Exception\UndefinedFunctionException\"?",
-            ],
-            [
-                [
-                    'type' => 1,
-                    'line' => 12,
-                    'file' => 'foo.php',
-                    'message' => 'Class \'Foo\\Bar\\UndefinedFunctionException\' not found',
-                ],
-                "Attempted to load class \"UndefinedFunctionException\" from namespace \"Foo\Bar\".\nDid you forget a \"use\" statement for \"Symfony\Component\Debug\Exception\UndefinedFunctionException\"?",
-                [$autoloader, 'loadClass'],
-            ],
-            [
-                [
-                    'type' => 1,
-                    'line' => 12,
-                    'file' => 'foo.php',
-                    'message' => 'Class \'Foo\\Bar\\UndefinedFunctionException\' not found',
-                ],
-                "Attempted to load class \"UndefinedFunctionException\" from namespace \"Foo\Bar\".\nDid you forget a \"use\" statement for \"Symfony\Component\Debug\Exception\UndefinedFunctionException\"?",
+                "/^Attempted to load class \"PEARClass\" from the global namespace.\nDid you forget a \"use\" statement for \"Symfony_Component_Debug_Tests_Fixtures_PEARClass\"\?$/",
                [$debugClassLoader, 'loadClass'],
            ],
            [
@@ -147,7 +125,37 @@ class ClassNotFoundFatalErrorHandlerTest extends TestCase
                    'file' => 'foo.php',
                    'message' => 'Class \'Foo\\Bar\\UndefinedFunctionException\' not found',
                ],
-                "Attempted to load class \"UndefinedFunctionException\" from namespace \"Foo\\Bar\".\nDid you forget a \"use\" statement for another namespace?",
+                "/^Attempted to load class \"UndefinedFunctionException\" from namespace \"Foo\\\\Bar\".\nDid you forget a \"use\" statement for .*\"Symfony\\\\Component\\\\Debug\\\\Exception\\\\UndefinedFunctionException\"\?$/",
+                [$debugClassLoader, 'loadClass'],
+            ],
+            [
+                [
+                    'type' => 1,
+                    'line' => 12,
+                    'file' => 'foo.php',
+                    'message' => 'Class \'Foo\\Bar\\UndefinedFunctionException\' not found',
+                ],
+                "/^Attempted to load class \"UndefinedFunctionException\" from namespace \"Foo\\\\Bar\".\nDid you forget a \"use\" statement for \"Symfony\\\\Component\\\\Debug\\\\Exception\\\\UndefinedFunctionException\"\?$/",
+                [$autoloader, 'loadClass'],
+            ],
+            [
+                [
+                    'type' => 1,
+                    'line' => 12,
+                    'file' => 'foo.php',
+                    'message' => 'Class \'Foo\\Bar\\UndefinedFunctionException\' not found',
+                ],
+                "/^Attempted to load class \"UndefinedFunctionException\" from namespace \"Foo\\\\Bar\".\nDid you forget a \"use\" statement for \"Symfony\\\\Component\\\\Debug\\\\Exception\\\\UndefinedFunctionException\"\?/",
+                [$debugClassLoader, 'loadClass'],
+            ],
+            [
+                [
+                    'type' => 1,
+                    'line' => 12,
+                    'file' => 'foo.php',
+                    'message' => 'Class \'Foo\\Bar\\UndefinedFunctionException\' not found',
+                ],
+                "/^Attempted to load class \"UndefinedFunctionException\" from namespace \"Foo\\\\Bar\".\nDid you forget a \"use\" statement for another namespace\?$/",
                function ($className) { /* do nothing here */ },
            ],
        ];
--- a/Tests/Fixtures/ClassWithAnnotatedParameters.php
+++ b/Tests/Fixtures/ClassWithAnnotatedParameters.php
@@ -0,0 +1,34 @@
+<?php
+
+namespace Symfony\Component\Debug\Tests\Fixtures;
+
+class ClassWithAnnotatedParameters
+{
+    /**
+     * @param string $foo this is a foo parameter
+     */
+    public function fooMethod(string $foo)
+    {
+    }
+
+    /**
+     * @param string $bar parameter not implemented yet
+     */
+    public function barMethod(/* string $bar = null */)
+    {
+    }
+
+    /**
+     * @param Quz $quz parameter not implemented yet
+     */
+    public function quzMethod(/* Quz $quz = null */)
+    {
+    }
+
+    /**
+     * @param true $yes
+     */
+    public function isSymfony()
+    {
+    }
+}
--- a/Tests/Fixtures/DefinitionInEvaluatedCode.php
+++ b/Tests/Fixtures/DefinitionInEvaluatedCode.php
@@ -0,0 +1,11 @@
+<?php
+
+namespace Symfony\Component\Debug\Tests\Fixtures;
+
+eval('
+    namespace Symfony\Component\Debug\Tests\Fixtures;
+
+    class DefinitionInEvaluatedCode
+    {
+    }
+');
--- a/Tests/Fixtures/ErrorHandlerThatUsesThePreviousOne.php
+++ b/Tests/Fixtures/ErrorHandlerThatUsesThePreviousOne.php
@@ -0,0 +1,22 @@
+<?php
+
+namespace Symfony\Component\Debug\Tests\Fixtures;
+
+class ErrorHandlerThatUsesThePreviousOne
+{
+    private static $previous;
+
+    public static function register()
+    {
+        $handler = new static();
+
+        self::$previous = set_error_handler([$handler, 'handleError']);
+
+        return $handler;
+    }
+
+    public function handleError($type, $message, $file, $line, $context)
+    {
+        return \call_user_func(self::$previous, $type, $message, $file, $line, $context);
+    }
+}
--- a/Tests/Fixtures/FinalClasses.php
+++ b/Tests/Fixtures/FinalClasses.php
@@ -30,6 +30,7 @@ class FinalClass3

 /**
 * @final
+ *
 * @author John Doe
 */
 class FinalClass4
@@ -63,7 +64,6 @@ class FinalClass6
 * @author John Doe
 *
 * @final another
- *
 *        multiline comment...
 *
 * @return string
@@ -76,6 +76,7 @@ class FinalClass7
 /**
 * @author John Doe
 * @final
+ *
 * @return string
 */
 class FinalClass8
--- a/Tests/Fixtures/FinalMethod.php
+++ b/Tests/Fixtures/FinalMethod.php
@@ -13,6 +13,8 @@ class FinalMethod

    /**
     * @final
+     *
+     * @return int
     */
    public function finalMethod2()
    {
--- a/Tests/Fixtures/InterfaceWithAnnotatedParameters.php
+++ b/Tests/Fixtures/InterfaceWithAnnotatedParameters.php
@@ -0,0 +1,27 @@
+<?php
+
+namespace Symfony\Component\Debug\Tests\Fixtures;
+
+/**
+ * Ensures a deprecation is triggered when a new parameter is not declared in child classes.
+ */
+interface InterfaceWithAnnotatedParameters
+{
+    /**
+     * @param bool $matrix
+     */
+    public function whereAmI();
+
+    /**
+     * @param       $noType
+     * @param callable(\Throwable|null $reason, mixed $value) $callback and a comment
+     * about this great param
+     * @param string                                          $param (comment with $dollar)
+     * @param $defined
+     * @param  callable  ($a,  $b)  $anotherOne
+     * @param callable (mixed $a, $b) $definedCallable
+     * @param Type$WithDollarIsStillAType $ccc
+     * @param \JustAType
+     */
+    public function iAmHere();
+}
--- a/Tests/Fixtures/LoggerThatSetAnErrorHandler.php
+++ b/Tests/Fixtures/LoggerThatSetAnErrorHandler.php
@@ -2,13 +2,14 @@

 namespace Symfony\Component\Debug\Tests\Fixtures;

-use Psr\Log\AbstractLogger;
+use Symfony\Component\Debug\BufferingLogger;

-class LoggerThatSetAnErrorHandler extends AbstractLogger
+class LoggerThatSetAnErrorHandler extends BufferingLogger
 {
    public function log($level, $message, array $context = [])
    {
        set_error_handler('is_string');
+        parent::log($level, $message, $context);
        restore_error_handler();
    }
 }
--- a/Tests/Fixtures/SubClassWithAnnotatedParameters.php
+++ b/Tests/Fixtures/SubClassWithAnnotatedParameters.php
@@ -0,0 +1,32 @@
+<?php
+
+namespace Symfony\Component\Debug\Tests\Fixtures;
+
+class SubClassWithAnnotatedParameters extends ClassWithAnnotatedParameters implements InterfaceWithAnnotatedParameters
+{
+    use TraitWithAnnotatedParameters;
+
+    public function fooMethod(string $foo)
+    {
+    }
+
+    public function barMethod($bar = null)
+    {
+    }
+
+    public function quzMethod()
+    {
+    }
+
+    public function whereAmI()
+    {
+    }
+
+    /**
+     * @param                      $defined
+     * @param Type\Does\Not\Matter $definedCallable
+     */
+    public function iAmHere()
+    {
+    }
+}
--- a/Tests/Fixtures/TraitWithAnnotatedParameters.php
+++ b/Tests/Fixtures/TraitWithAnnotatedParameters.php
@@ -0,0 +1,13 @@
+<?php
+
+namespace Symfony\Component\Debug\Tests\Fixtures;
+
+trait TraitWithAnnotatedParameters
+{
+    /**
+     * `@param` annotations in traits are not parsed.
+     */
+    public function isSymfony()
+    {
+    }
+}
--- a/Tests/Fixtures/VirtualClass.php
+++ b/Tests/Fixtures/VirtualClass.php
@@ -0,0 +1,11 @@
+<?php
+
+namespace Symfony\Component\Debug\Tests\Fixtures;
+
+/**
+ * @method string classMethod()
+ */
+class VirtualClass
+{
+    use VirtualTrait;
+}
--- a/Tests/Fixtures/VirtualClassMagicCall.php
+++ b/Tests/Fixtures/VirtualClassMagicCall.php
@@ -0,0 +1,18 @@
+<?php
+
+namespace Symfony\Component\Debug\Tests\Fixtures;
+
+/**
+ * @method string magicMethod()
+ * @method static string staticMagicMethod()
+ */
+class VirtualClassMagicCall
+{
+    public static function __callStatic($name, $arguments)
+    {
+    }
+
+    public function __call($name, $arguments)
+    {
+    }
+}
--- a/Tests/Fixtures/VirtualInterface.php
+++ b/Tests/Fixtures/VirtualInterface.php
@@ -0,0 +1,34 @@
+<?php
+
+namespace Symfony\Component\Debug\Tests\Fixtures;
+
+/**
+ * @method string interfaceMethod()
+ * @method        sameLineInterfaceMethod($arg)
+ * @method sameLineInterfaceMethodNoBraces
+ *
+ * Ignored
+ * @method
+ * @method
+ *
+ * Not ignored
+ * @method newLineInterfaceMethod() Some description!
+ * @method \stdClass newLineInterfaceMethodNoBraces Description
+ *
+ * Invalid
+ * @method unknownType invalidInterfaceMethod()
+ * @method unknownType|string invalidInterfaceMethodNoBraces
+ *
+ * Complex
+ * @method              complexInterfaceMethod($arg, ...$args)
+ * @method string[]|int complexInterfaceMethodTyped($arg, int ...$args) Description ...
+ *
+ * Static
+ * @method static Foo&Bar staticMethod()
+ * @method static staticMethodNoBraces
+ * @method static \stdClass staticMethodTyped(int $arg) Description
+ * @method static \stdClass[] staticMethodTypedNoBraces
+ */
+interface VirtualInterface
+{
+}
--- a/Tests/Fixtures/VirtualSubInterface.php
+++ b/Tests/Fixtures/VirtualSubInterface.php
@@ -0,0 +1,10 @@
+<?php
+
+namespace Symfony\Component\Debug\Tests\Fixtures;
+
+/**
+ * @method string subInterfaceMethod()
+ */
+interface VirtualSubInterface extends VirtualInterface
+{
+}
--- a/Tests/Fixtures/VirtualTrait.php
+++ b/Tests/Fixtures/VirtualTrait.php
@@ -0,0 +1,10 @@
+<?php
+
+namespace Symfony\Component\Debug\Tests\Fixtures;
+
+/**
+ * @method string traitMethod()
+ */
+trait VirtualTrait
+{
+}
--- a/Tests/MockExceptionHandler.php
+++ b/Tests/MockExceptionHandler.php
@@ -1,24 +0,0 @@
-<?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\Debug\Tests;
-
-use Symfony\Component\Debug\ExceptionHandler;
-
-class MockExceptionHandler extends ExceptionHandler
-{
-    public $e;
-
-    public function handle(\Exception $e)
-    {
-        $this->e = $e;
-    }
-}
--- a/Tests/phpt/fatal_with_nested_handlers.phpt
+++ b/Tests/phpt/fatal_with_nested_handlers.phpt
@@ -24,7 +24,7 @@ var_dump([
 $eHandler[0]->setExceptionHandler('print_r');

 if (true) {
-    class Broken implements \Serializable
+    class Broken implements \JsonSerializable
    {
    }
 }
@@ -37,6 +37,6 @@ array(1) {
 }
 object(Symfony\Component\Debug\Exception\FatalErrorException)#%d (%d) {
  ["message":protected]=>
-  string(199) "Error: Class Symfony\Component\Debug\Broken contains 2 abstract methods and must therefore be declared abstract or implement the remaining methods (Serializable::serialize, Serializable::unserialize)"
+  string(179) "Error: Class Symfony\Component\Debug\Broken contains 1 abstract method and must therefore be declared abstract or implement the remaining methods (JsonSerializable::jsonSerialize)"
 %a
 }
--- a/composer.json
+++ b/composer.json
@@ -34,7 +34,7 @@
    "minimum-stability": "dev",
    "extra": {
        "branch-alias": {
-            "dev-master": "4.1-dev"
+            "dev-master": "4.3-dev"
        }
    }
 }