From aa79381fe4e52004650218130e2c52d6951e0139 Mon Sep 17 00:00:00 2001
From: Simon Berger <simon_-berger@web.de>
Date: Sun, 24 Jan 2021 23:22:56 +0100
Subject: [PATCH] Changed private static array-properties to const

---
 .../Monolog/Command/ServerLogCommand.php      |  4 +-
 .../Monolog/Formatter/ConsoleFormatter.php    |  6 +--
 .../Bridge/Twig/UndefinedCallableHandler.php  | 18 ++++----
 .../Command/ServerLogCommand.php              |  4 +-
 src/Symfony/Component/BrowserKit/Cookie.php   |  6 +--
 .../Compiler/RegisterEnvVarProcessorsPass.php |  6 +--
 .../Compiler/ValidateEnvPlaceholdersPass.php  |  6 +--
 .../DependencyInjection/ContainerBuilder.php  |  4 +-
 .../Loader/YamlFileLoader.php                 | 18 ++++----
 .../ExpressionLanguage/Node/BinaryNode.php    | 16 +++----
 .../ExpressionLanguage/Node/UnaryNode.php     |  4 +-
 .../DateIntervalToArrayTransformer.php        |  6 +--
 .../Extension/Core/Type/DateIntervalType.php  |  4 +-
 .../Form/Extension/Core/Type/DateTimeType.php |  4 +-
 .../Form/Extension/Core/Type/DateType.php     | 12 +++---
 .../Form/Extension/Core/Type/FileType.php     |  4 +-
 .../Form/Extension/Core/Type/TimeType.php     |  8 ++--
 .../Form/Extension/Core/Type/WeekType.php     |  6 +--
 .../Component/Form/NativeRequestHandler.php   |  8 ++--
 .../Component/HttpFoundation/Cookie.php       |  6 +--
 .../Component/HttpFoundation/FileBag.php      |  8 ++--
 .../Component/HttpFoundation/Request.php      | 16 +++----
 .../HttpCache/ResponseCacheStrategy.php       |  8 ++--
 .../Component/HttpKernel/Log/Logger.php       | 10 ++---
 src/Symfony/Component/Inflector/Inflector.php | 14 +++----
 .../Data/Generator/CurrencyDataGenerator.php  |  4 +-
 .../Data/Generator/LanguageDataGenerator.php  | 16 +++----
 .../Data/Generator/RegionDataGenerator.php    | 16 +++----
 .../Data/Generator/ScriptDataGenerator.php    |  4 +-
 .../Component/Intl/Globals/IntlGlobals.php    | 10 ++---
 .../Intl/NumberFormatter/NumberFormatter.php  | 42 +++++++++----------
 .../Component/Intl/Tests/CountriesTest.php    | 22 +++++-----
 .../Component/Intl/Tests/CurrenciesTest.php   | 18 ++++----
 .../Bundle/Reader/BundleEntryReaderTest.php   | 24 +++++------
 .../Provider/AbstractDataProviderTest.php     |  8 ++--
 .../Component/Intl/Tests/LanguagesTest.php    | 32 +++++++-------
 .../AbstractNumberFormatterTest.php           |  6 +--
 .../Intl/Tests/ResourceBundleTestCase.php     |  8 ++--
 .../Component/Intl/Tests/TimezonesTest.php    | 12 +++---
 src/Symfony/Component/Ldap/Ldap.php           |  8 ++--
 .../Component/Mime/Encoder/QpEncoder.php      |  6 +--
 src/Symfony/Component/Mime/Header/Headers.php |  6 +--
 src/Symfony/Component/Mime/MimeTypes.php      |  8 ++--
 .../OptionsResolver/OptionsResolver.php       |  6 +--
 .../PropertyAccess/PropertyAccessor.php       |  6 +--
 .../Routing/Loader/YamlFileLoader.php         |  6 +--
 .../Normalizer/DataUriNormalizer.php          |  4 +-
 .../Normalizer/DateTimeNormalizer.php         |  4 +-
 .../Validator/Constraints/EmailValidator.php  |  4 +-
 .../Validator/Constraints/FileValidator.php   |  4 +-
 .../Validator/Constraints/IbanValidator.php   |  6 +--
 .../Component/VarDumper/Caster/AmqpCaster.php |  8 ++--
 .../Component/VarDumper/Caster/DOMCaster.php  | 12 +++---
 .../Component/VarDumper/Caster/PdoCaster.php  |  4 +-
 .../VarDumper/Caster/PgSqlCaster.php          | 20 ++++-----
 .../VarDumper/Caster/RedisCaster.php          | 28 ++++++-------
 .../VarDumper/Caster/ReflectionCaster.php     |  4 +-
 .../Component/VarDumper/Caster/SplCaster.php  |  4 +-
 .../VarDumper/Caster/SymfonyCaster.php        |  4 +-
 .../VarDumper/Caster/XmlReaderCaster.php      |  4 +-
 .../VarDumper/Caster/XmlResourceCaster.php    |  6 +--
 src/Symfony/Component/Yaml/Escaper.php        |  6 +--
 62 files changed, 296 insertions(+), 300 deletions(-)

diff --git a/src/Symfony/Bridge/Monolog/Command/ServerLogCommand.php b/src/Symfony/Bridge/Monolog/Command/ServerLogCommand.php
index f04db50c8c..bf3433e154 100644
--- a/src/Symfony/Bridge/Monolog/Command/ServerLogCommand.php
+++ b/src/Symfony/Bridge/Monolog/Command/ServerLogCommand.php
@@ -28,7 +28,7 @@ use Symfony\Component\ExpressionLanguage\ExpressionLanguage;
  */
 class ServerLogCommand extends Command
 {
-    private static $bgColor = ['black', 'blue', 'cyan', 'green', 'magenta', 'red', 'white', 'yellow'];
+    private const BG_COLOR = ['black', 'blue', 'cyan', 'green', 'magenta', 'red', 'white', 'yellow'];
 
     private $el;
     private $handler;
@@ -151,7 +151,7 @@ EOF
         if (isset($record['log_id'])) {
             $clientId = unpack('H*', $record['log_id'])[1];
         }
-        $logBlock = sprintf('<bg=%s> </>', self::$bgColor[$clientId % 8]);
+        $logBlock = sprintf('<bg=%s> </>', self::BG_COLOR[$clientId % 8]);
         $output->write($logBlock);
 
         $this->handler->handle($record);
diff --git a/src/Symfony/Bridge/Monolog/Formatter/ConsoleFormatter.php b/src/Symfony/Bridge/Monolog/Formatter/ConsoleFormatter.php
index 1c7e6afa99..d232d68cd9 100644
--- a/src/Symfony/Bridge/Monolog/Formatter/ConsoleFormatter.php
+++ b/src/Symfony/Bridge/Monolog/Formatter/ConsoleFormatter.php
@@ -30,7 +30,7 @@ class ConsoleFormatter implements FormatterInterface
     public const SIMPLE_FORMAT = "%datetime% %start_tag%%level_name%%end_tag% <comment>[%channel%]</> %message%%context%%extra%\n";
     public const SIMPLE_DATE = 'H:i:s';
 
-    private static $levelColorMap = [
+    private const LEVEL_COLOR_MAP = [
         Logger::DEBUG => 'fg=white',
         Logger::INFO => 'fg=green',
         Logger::NOTICE => 'fg=blue',
@@ -104,8 +104,6 @@ class ConsoleFormatter implements FormatterInterface
     {
         $record = $this->replacePlaceHolder($record);
 
-        $levelColor = self::$levelColorMap[$record['level']];
-
         if (!$this->options['ignore_empty_context_and_extra'] || !empty($record['context'])) {
             $context = ($this->options['multiline'] ? "\n" : ' ').$this->dumpData($record['context']);
         } else {
@@ -122,7 +120,7 @@ class ConsoleFormatter implements FormatterInterface
             '%datetime%' => $record['datetime'] instanceof \DateTimeInterface
                 ? $record['datetime']->format($this->options['date_format'])
                 : $record['datetime'],
-            '%start_tag%' => sprintf('<%s>', $levelColor),
+            '%start_tag%' => sprintf('<%s>', self::LEVEL_COLOR_MAP[$record['level']]),
             '%level_name%' => sprintf($this->options['level_name_format'], $record['level_name']),
             '%end_tag%' => '</>',
             '%channel%' => $record['channel'],
diff --git a/src/Symfony/Bridge/Twig/UndefinedCallableHandler.php b/src/Symfony/Bridge/Twig/UndefinedCallableHandler.php
index fa3049d3dd..16381fddac 100644
--- a/src/Symfony/Bridge/Twig/UndefinedCallableHandler.php
+++ b/src/Symfony/Bridge/Twig/UndefinedCallableHandler.php
@@ -19,7 +19,7 @@ use Twig\Error\SyntaxError;
  */
 class UndefinedCallableHandler
 {
-    private static $filterComponents = [
+    private const FILTER_COMPONENTS = [
         'humanize' => 'form',
         'trans' => 'translation',
         'transchoice' => 'translation',
@@ -27,7 +27,7 @@ class UndefinedCallableHandler
         'yaml_dump' => 'yaml',
     ];
 
-    private static $functionComponents = [
+    private const FUNCTION_COMPONENTS = [
         'asset' => 'asset',
         'asset_version' => 'asset',
         'dump' => 'debug-bundle',
@@ -57,7 +57,7 @@ class UndefinedCallableHandler
         'workflow_marked_places' => 'workflow',
     ];
 
-    private static $fullStackEnable = [
+    private const FULL_STACK_ENABLE = [
         'form' => 'enable "framework.form"',
         'security-core' => 'add the "SecurityBundle"',
         'security-http' => 'add the "SecurityBundle"',
@@ -67,30 +67,30 @@ class UndefinedCallableHandler
 
     public static function onUndefinedFilter(string $name): bool
     {
-        if (!isset(self::$filterComponents[$name])) {
+        if (!isset(self::FILTER_COMPONENTS[$name])) {
             return false;
         }
 
-        self::onUndefined($name, 'filter', self::$filterComponents[$name]);
+        self::onUndefined($name, 'filter', self::FILTER_COMPONENTS[$name]);
 
         return true;
     }
 
     public static function onUndefinedFunction(string $name): bool
     {
-        if (!isset(self::$functionComponents[$name])) {
+        if (!isset(self::FUNCTION_COMPONENTS[$name])) {
             return false;
         }
 
-        self::onUndefined($name, 'function', self::$functionComponents[$name]);
+        self::onUndefined($name, 'function', self::FUNCTION_COMPONENTS[$name]);
 
         return true;
     }
 
     private static function onUndefined(string $name, string $type, string $component)
     {
-        if (class_exists(FullStack::class) && isset(self::$fullStackEnable[$component])) {
-            throw new SyntaxError(sprintf('Did you forget to %s? Unknown %s "%s".', self::$fullStackEnable[$component], $type, $name));
+        if (class_exists(FullStack::class) && isset(self::FULL_STACK_ENABLE[$component])) {
+            throw new SyntaxError(sprintf('Did you forget to %s? Unknown %s "%s".', self::FULL_STACK_ENABLE[$component], $type, $name));
         }
 
         throw new SyntaxError(sprintf('Did you forget to run "composer require symfony/%s"? Unknown %s "%s".', $component, $type, $name));
diff --git a/src/Symfony/Bundle/WebServerBundle/Command/ServerLogCommand.php b/src/Symfony/Bundle/WebServerBundle/Command/ServerLogCommand.php
index c10e2d8a2b..10d06ddf5a 100644
--- a/src/Symfony/Bundle/WebServerBundle/Command/ServerLogCommand.php
+++ b/src/Symfony/Bundle/WebServerBundle/Command/ServerLogCommand.php
@@ -30,7 +30,7 @@ use Symfony\Component\ExpressionLanguage\ExpressionLanguage;
  */
 class ServerLogCommand extends Command
 {
-    private static $bgColor = ['black', 'blue', 'cyan', 'green', 'magenta', 'red', 'white', 'yellow'];
+    private const BG_COLOR = ['black', 'blue', 'cyan', 'green', 'magenta', 'red', 'white', 'yellow'];
 
     private $el;
     private $handler;
@@ -155,7 +155,7 @@ EOF
         if (isset($record['log_id'])) {
             $clientId = unpack('H*', $record['log_id'])[1];
         }
-        $logBlock = sprintf('<bg=%s> </>', self::$bgColor[$clientId % 8]);
+        $logBlock = sprintf('<bg=%s> </>', self::BG_COLOR[$clientId % 8]);
         $output->write($logBlock);
 
         $this->handler->handle($record);
diff --git a/src/Symfony/Component/BrowserKit/Cookie.php b/src/Symfony/Component/BrowserKit/Cookie.php
index e0232e5150..77b330c025 100644
--- a/src/Symfony/Component/BrowserKit/Cookie.php
+++ b/src/Symfony/Component/BrowserKit/Cookie.php
@@ -22,7 +22,7 @@ class Cookie
      * Handles dates as defined by RFC 2616 section 3.3.1, and also some other
      * non-standard, but common formats.
      */
-    private static $dateFormats = [
+    private const DATE_FORMATS = [
         'D, d M Y H:i:s T',
         'D, d-M-y H:i:s T',
         'D, d-M-Y H:i:s T',
@@ -92,7 +92,7 @@ class Cookie
 
         if (null !== $this->expires) {
             $dateTime = \DateTime::createFromFormat('U', $this->expires, new \DateTimeZone('GMT'));
-            $cookie .= '; expires='.str_replace('+0000', '', $dateTime->format(self::$dateFormats[0]));
+            $cookie .= '; expires='.str_replace('+0000', '', $dateTime->format(self::DATE_FORMATS[0]));
         }
 
         if ('' !== $this->domain) {
@@ -208,7 +208,7 @@ class Cookie
             $dateValue = substr($dateValue, 1, -1);
         }
 
-        foreach (self::$dateFormats as $dateFormat) {
+        foreach (self::DATE_FORMATS as $dateFormat) {
             if (false !== $date = \DateTime::createFromFormat($dateFormat, $dateValue, new \DateTimeZone('GMT'))) {
                 return $date->format('U');
             }
diff --git a/src/Symfony/Component/DependencyInjection/Compiler/RegisterEnvVarProcessorsPass.php b/src/Symfony/Component/DependencyInjection/Compiler/RegisterEnvVarProcessorsPass.php
index a9a133be2a..251889ebed 100644
--- a/src/Symfony/Component/DependencyInjection/Compiler/RegisterEnvVarProcessorsPass.php
+++ b/src/Symfony/Component/DependencyInjection/Compiler/RegisterEnvVarProcessorsPass.php
@@ -25,7 +25,7 @@ use Symfony\Component\DependencyInjection\Reference;
  */
 class RegisterEnvVarProcessorsPass implements CompilerPassInterface
 {
-    private static $allowedTypes = ['array', 'bool', 'float', 'int', 'string'];
+    private const ALLOWED_TYPES = ['array', 'bool', 'float', 'int', 'string'];
 
     public function process(ContainerBuilder $container)
     {
@@ -65,8 +65,8 @@ class RegisterEnvVarProcessorsPass implements CompilerPassInterface
         $types = explode('|', $types);
 
         foreach ($types as $type) {
-            if (!\in_array($type, self::$allowedTypes)) {
-                throw new InvalidArgumentException(sprintf('Invalid type "%s" returned by "%s::getProvidedTypes()", expected one of "%s".', $type, $class, implode('", "', self::$allowedTypes)));
+            if (!\in_array($type, self::ALLOWED_TYPES)) {
+                throw new InvalidArgumentException(sprintf('Invalid type "%s" returned by "%s::getProvidedTypes()", expected one of "%s".', $type, $class, implode('", "', self::ALLOWED_TYPES)));
             }
         }
 
diff --git a/src/Symfony/Component/DependencyInjection/Compiler/ValidateEnvPlaceholdersPass.php b/src/Symfony/Component/DependencyInjection/Compiler/ValidateEnvPlaceholdersPass.php
index 8fd84fac00..cae01c61dd 100644
--- a/src/Symfony/Component/DependencyInjection/Compiler/ValidateEnvPlaceholdersPass.php
+++ b/src/Symfony/Component/DependencyInjection/Compiler/ValidateEnvPlaceholdersPass.php
@@ -26,7 +26,7 @@ use Symfony\Component\DependencyInjection\ParameterBag\ParameterBag;
  */
 class ValidateEnvPlaceholdersPass implements CompilerPassInterface
 {
-    private static $typeFixtures = ['array' => [], 'bool' => false, 'float' => 0.0, 'int' => 0, 'string' => ''];
+    private const TYPE_FIXTURES = ['array' => [], 'bool' => false, 'float' => 0.0, 'int' => 0, 'string' => ''];
 
     private $extensionConfig = [];
 
@@ -52,13 +52,13 @@ class ValidateEnvPlaceholdersPass implements CompilerPassInterface
             foreach ($resolvingBag->getEnvPlaceholders() + $resolvingBag->getUnusedEnvPlaceholders() as $env => $placeholders) {
                 $values = [];
                 if (false === $i = strpos($env, ':')) {
-                    $default = $defaultBag->has("env($env)") ? $defaultBag->get("env($env)") : self::$typeFixtures['string'];
+                    $default = $defaultBag->has("env($env)") ? $defaultBag->get("env($env)") : self::TYPE_FIXTURES['string'];
                     $defaultType = null !== $default ? self::getType($default) : 'string';
                     $values[$defaultType] = $default;
                 } else {
                     $prefix = substr($env, 0, $i);
                     foreach ($envTypes[$prefix] ?? ['string'] as $type) {
-                        $values[$type] = self::$typeFixtures[$type] ?? null;
+                        $values[$type] = self::TYPE_FIXTURES[$type] ?? null;
                     }
                 }
                 foreach ($placeholders as $placeholder) {
diff --git a/src/Symfony/Component/DependencyInjection/ContainerBuilder.php b/src/Symfony/Component/DependencyInjection/ContainerBuilder.php
index 027334ceb6..57e7963846 100644
--- a/src/Symfony/Component/DependencyInjection/ContainerBuilder.php
+++ b/src/Symfony/Component/DependencyInjection/ContainerBuilder.php
@@ -126,7 +126,7 @@ class ContainerBuilder extends Container implements TaggedContainerInterface
 
     private $removedBindingIds = [];
 
-    private static $internalTypes = [
+    private const INTERNAL_TYPES = [
         'int' => true,
         'float' => true,
         'string' => true,
@@ -339,7 +339,7 @@ class ContainerBuilder extends Container implements TaggedContainerInterface
             return null;
         }
 
-        if (isset(self::$internalTypes[$class])) {
+        if (isset(self::INTERNAL_TYPES[$class])) {
             return null;
         }
 
diff --git a/src/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php b/src/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php
index 9e15ca8339..1133254c6c 100644
--- a/src/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php
+++ b/src/Symfony/Component/DependencyInjection/Loader/YamlFileLoader.php
@@ -38,7 +38,7 @@ use Symfony\Component\Yaml\Yaml;
  */
 class YamlFileLoader extends FileLoader
 {
-    private static $serviceKeywords = [
+    private const SERVICE_KEYWORDS = [
         'alias' => 'alias',
         'parent' => 'parent',
         'class' => 'class',
@@ -64,7 +64,7 @@ class YamlFileLoader extends FileLoader
         'bind' => 'bind',
     ];
 
-    private static $prototypeKeywords = [
+    private const PROTOTYPE_KEYWORDS = [
         'resource' => 'resource',
         'namespace' => 'namespace',
         'exclude' => 'exclude',
@@ -85,7 +85,7 @@ class YamlFileLoader extends FileLoader
         'bind' => 'bind',
     ];
 
-    private static $instanceofKeywords = [
+    private const INSTANCEOF_KEYWORDS = [
         'shared' => 'shared',
         'lazy' => 'lazy',
         'public' => 'public',
@@ -97,7 +97,7 @@ class YamlFileLoader extends FileLoader
         'bind' => 'bind',
     ];
 
-    private static $defaultsKeywords = [
+    private const DEFAULTS_KEYWORDS = [
         'public' => 'public',
         'tags' => 'tags',
         'autowire' => 'autowire',
@@ -250,8 +250,8 @@ class YamlFileLoader extends FileLoader
         }
 
         foreach ($defaults as $key => $default) {
-            if (!isset(self::$defaultsKeywords[$key])) {
-                throw new InvalidArgumentException(sprintf('The configuration key "%s" cannot be used to define a default value in "%s". Allowed keys are "%s".', $key, $file, implode('", "', self::$defaultsKeywords)));
+            if (!isset(self::DEFAULTS_KEYWORDS[$key])) {
+                throw new InvalidArgumentException(sprintf('The configuration key "%s" cannot be used to define a default value in "%s". Allowed keys are "%s".', $key, $file, implode('", "', self::DEFAULTS_KEYWORDS)));
             }
         }
 
@@ -864,11 +864,11 @@ class YamlFileLoader extends FileLoader
     private function checkDefinition(string $id, array $definition, string $file)
     {
         if ($this->isLoadingInstanceof) {
-            $keywords = self::$instanceofKeywords;
+            $keywords = self::INSTANCEOF_KEYWORDS;
         } elseif (isset($definition['resource']) || isset($definition['namespace'])) {
-            $keywords = self::$prototypeKeywords;
+            $keywords = self::PROTOTYPE_KEYWORDS;
         } else {
-            $keywords = self::$serviceKeywords;
+            $keywords = self::SERVICE_KEYWORDS;
         }
 
         foreach ($definition as $key => $value) {
diff --git a/src/Symfony/Component/ExpressionLanguage/Node/BinaryNode.php b/src/Symfony/Component/ExpressionLanguage/Node/BinaryNode.php
index 191970ca1e..3820f880e7 100644
--- a/src/Symfony/Component/ExpressionLanguage/Node/BinaryNode.php
+++ b/src/Symfony/Component/ExpressionLanguage/Node/BinaryNode.php
@@ -20,13 +20,13 @@ use Symfony\Component\ExpressionLanguage\Compiler;
  */
 class BinaryNode extends Node
 {
-    private static $operators = [
+    private const OPERATORS = [
         '~' => '.',
         'and' => '&&',
         'or' => '||',
     ];
 
-    private static $functions = [
+    private const FUNCTIONS = [
         '**' => 'pow',
         '..' => 'range',
         'in' => 'in_array',
@@ -57,9 +57,9 @@ class BinaryNode extends Node
             return;
         }
 
-        if (isset(self::$functions[$operator])) {
+        if (isset(self::FUNCTIONS[$operator])) {
             $compiler
-                ->raw(sprintf('%s(', self::$functions[$operator]))
+                ->raw(sprintf('%s(', self::FUNCTIONS[$operator]))
                 ->compile($this->nodes['left'])
                 ->raw(', ')
                 ->compile($this->nodes['right'])
@@ -69,8 +69,8 @@ class BinaryNode extends Node
             return;
         }
 
-        if (isset(self::$operators[$operator])) {
-            $operator = self::$operators[$operator];
+        if (isset(self::OPERATORS[$operator])) {
+            $operator = self::OPERATORS[$operator];
         }
 
         $compiler
@@ -89,13 +89,13 @@ class BinaryNode extends Node
         $operator = $this->attributes['operator'];
         $left = $this->nodes['left']->evaluate($functions, $values);
 
-        if (isset(self::$functions[$operator])) {
+        if (isset(self::FUNCTIONS[$operator])) {
             $right = $this->nodes['right']->evaluate($functions, $values);
 
             if ('not in' === $operator) {
                 return !\in_array($left, $right);
             }
-            $f = self::$functions[$operator];
+            $f = self::FUNCTIONS[$operator];
 
             return $f($left, $right);
         }
diff --git a/src/Symfony/Component/ExpressionLanguage/Node/UnaryNode.php b/src/Symfony/Component/ExpressionLanguage/Node/UnaryNode.php
index abf2cc6bac..dd6fba1df2 100644
--- a/src/Symfony/Component/ExpressionLanguage/Node/UnaryNode.php
+++ b/src/Symfony/Component/ExpressionLanguage/Node/UnaryNode.php
@@ -20,7 +20,7 @@ use Symfony\Component\ExpressionLanguage\Compiler;
  */
 class UnaryNode extends Node
 {
-    private static $operators = [
+    private const OPERATORS = [
         '!' => '!',
         'not' => '!',
         '+' => '+',
@@ -39,7 +39,7 @@ class UnaryNode extends Node
     {
         $compiler
             ->raw('(')
-            ->raw(self::$operators[$this->attributes['operator']])
+            ->raw(self::OPERATORS[$this->attributes['operator']])
             ->compile($this->nodes['node'])
             ->raw(')')
         ;
diff --git a/src/Symfony/Component/Form/Extension/Core/DataTransformer/DateIntervalToArrayTransformer.php b/src/Symfony/Component/Form/Extension/Core/DataTransformer/DateIntervalToArrayTransformer.php
index 3f6c23f555..bb461bb3b0 100644
--- a/src/Symfony/Component/Form/Extension/Core/DataTransformer/DateIntervalToArrayTransformer.php
+++ b/src/Symfony/Component/Form/Extension/Core/DataTransformer/DateIntervalToArrayTransformer.php
@@ -30,7 +30,7 @@ class DateIntervalToArrayTransformer implements DataTransformerInterface
     public const SECONDS = 'seconds';
     public const INVERT = 'invert';
 
-    private static $availableFields = [
+    private const AVAILABLE_FIELDS = [
         self::YEARS => 'y',
         self::MONTHS => 'm',
         self::DAYS => 'd',
@@ -85,7 +85,7 @@ class DateIntervalToArrayTransformer implements DataTransformerInterface
             throw new UnexpectedTypeException($dateInterval, \DateInterval::class);
         }
         $result = [];
-        foreach (self::$availableFields as $field => $char) {
+        foreach (self::AVAILABLE_FIELDS as $field => $char) {
             $result[$field] = $dateInterval->format('%'.($this->pad ? strtoupper($char) : $char));
         }
         if (\in_array('weeks', $this->fields, true)) {
@@ -134,7 +134,7 @@ class DateIntervalToArrayTransformer implements DataTransformerInterface
         if (isset($value['invert']) && !\is_bool($value['invert'])) {
             throw new TransformationFailedException('The value of "invert" must be boolean.');
         }
-        foreach (self::$availableFields as $field => $char) {
+        foreach (self::AVAILABLE_FIELDS as $field => $char) {
             if ('invert' !== $field && isset($value[$field]) && !ctype_digit((string) $value[$field])) {
                 throw new TransformationFailedException(sprintf('This amount of "%s" is invalid.', $field));
             }
diff --git a/src/Symfony/Component/Form/Extension/Core/Type/DateIntervalType.php b/src/Symfony/Component/Form/Extension/Core/Type/DateIntervalType.php
index 981740fdaa..af24b00644 100644
--- a/src/Symfony/Component/Form/Extension/Core/Type/DateIntervalType.php
+++ b/src/Symfony/Component/Form/Extension/Core/Type/DateIntervalType.php
@@ -37,7 +37,7 @@ class DateIntervalType extends AbstractType
         'minutes',
         'seconds',
     ];
-    private static $widgets = [
+    private const WIDGETS = [
         'text' => TextType::class,
         'integer' => IntegerType::class,
         'choice' => ChoiceType::class,
@@ -112,7 +112,7 @@ class DateIntervalType extends AbstractType
                         $childOptions['choices'] = $options[$part];
                         $childOptions['placeholder'] = $options['placeholder'][$part];
                     }
-                    $childForm = $builder->create($part, self::$widgets[$options['widget']], $childOptions);
+                    $childForm = $builder->create($part, self::WIDGETS[$options['widget']], $childOptions);
                     if ('integer' === $options['widget']) {
                         $childForm->addModelTransformer(
                             new ReversedTransformer(
diff --git a/src/Symfony/Component/Form/Extension/Core/Type/DateTimeType.php b/src/Symfony/Component/Form/Extension/Core/Type/DateTimeType.php
index e542351a02..8c96195485 100644
--- a/src/Symfony/Component/Form/Extension/Core/Type/DateTimeType.php
+++ b/src/Symfony/Component/Form/Extension/Core/Type/DateTimeType.php
@@ -40,7 +40,7 @@ class DateTimeType extends AbstractType
      */
     public const HTML5_FORMAT = "yyyy-MM-dd'T'HH:mm:ss";
 
-    private static $acceptedFormats = [
+    private const ACCEPTED_FORMATS = [
         \IntlDateFormatter::FULL,
         \IntlDateFormatter::LONG,
         \IntlDateFormatter::MEDIUM,
@@ -71,7 +71,7 @@ class DateTimeType extends AbstractType
         $calendar = \IntlDateFormatter::GREGORIAN;
         $pattern = \is_string($options['format']) ? $options['format'] : null;
 
-        if (!\in_array($dateFormat, self::$acceptedFormats, true)) {
+        if (!\in_array($dateFormat, self::ACCEPTED_FORMATS, true)) {
             throw new InvalidOptionsException('The "date_format" option must be one of the IntlDateFormatter constants (FULL, LONG, MEDIUM, SHORT) or a string representing a custom format.');
         }
 
diff --git a/src/Symfony/Component/Form/Extension/Core/Type/DateType.php b/src/Symfony/Component/Form/Extension/Core/Type/DateType.php
index 47ac0ca036..f6cca90814 100644
--- a/src/Symfony/Component/Form/Extension/Core/Type/DateType.php
+++ b/src/Symfony/Component/Form/Extension/Core/Type/DateType.php
@@ -31,14 +31,14 @@ class DateType extends AbstractType
     public const DEFAULT_FORMAT = \IntlDateFormatter::MEDIUM;
     public const HTML5_FORMAT = 'yyyy-MM-dd';
 
-    private static $acceptedFormats = [
+    private const ACCEPTED_FORMATS = [
         \IntlDateFormatter::FULL,
         \IntlDateFormatter::LONG,
         \IntlDateFormatter::MEDIUM,
         \IntlDateFormatter::SHORT,
     ];
 
-    private static $widgets = [
+    private const WIDGETS = [
         'text' => 'Symfony\Component\Form\Extension\Core\Type\TextType',
         'choice' => 'Symfony\Component\Form\Extension\Core\Type\ChoiceType',
     ];
@@ -53,7 +53,7 @@ class DateType extends AbstractType
         $calendar = \IntlDateFormatter::GREGORIAN;
         $pattern = \is_string($options['format']) ? $options['format'] : '';
 
-        if (!\in_array($dateFormat, self::$acceptedFormats, true)) {
+        if (!\in_array($dateFormat, self::ACCEPTED_FORMATS, true)) {
             throw new InvalidOptionsException('The "format" option must be one of the IntlDateFormatter constants (FULL, LONG, MEDIUM, SHORT) or a string representing a custom format.');
         }
 
@@ -155,9 +155,9 @@ class DateType extends AbstractType
             }
 
             $builder
-                ->add('year', self::$widgets[$options['widget']], $yearOptions)
-                ->add('month', self::$widgets[$options['widget']], $monthOptions)
-                ->add('day', self::$widgets[$options['widget']], $dayOptions)
+                ->add('year', self::WIDGETS[$options['widget']], $yearOptions)
+                ->add('month', self::WIDGETS[$options['widget']], $monthOptions)
+                ->add('day', self::WIDGETS[$options['widget']], $dayOptions)
                 ->addViewTransformer(new DateTimeToArrayTransformer(
                     $options['model_timezone'], $options['view_timezone'], ['year', 'month', 'day']
                 ))
diff --git a/src/Symfony/Component/Form/Extension/Core/Type/FileType.php b/src/Symfony/Component/Form/Extension/Core/Type/FileType.php
index 4ccf94c920..e26cedd37c 100644
--- a/src/Symfony/Component/Form/Extension/Core/Type/FileType.php
+++ b/src/Symfony/Component/Form/Extension/Core/Type/FileType.php
@@ -28,7 +28,7 @@ class FileType extends AbstractType
     public const KIB_BYTES = 1024;
     public const MIB_BYTES = 1048576;
 
-    private static $suffixes = [
+    private const SUFFIXES = [
         1 => 'bytes',
         self::KIB_BYTES => 'KiB',
         self::MIB_BYTES => 'MiB',
@@ -244,7 +244,7 @@ class FileType extends AbstractType
             $sizeAsString = (string) round($size / $coef, 2);
         }
 
-        return [$limitAsString, self::$suffixes[$coef]];
+        return [$limitAsString, self::SUFFIXES[$coef]];
     }
 
     /**
diff --git a/src/Symfony/Component/Form/Extension/Core/Type/TimeType.php b/src/Symfony/Component/Form/Extension/Core/Type/TimeType.php
index f122754642..58af6f1d45 100644
--- a/src/Symfony/Component/Form/Extension/Core/Type/TimeType.php
+++ b/src/Symfony/Component/Form/Extension/Core/Type/TimeType.php
@@ -28,7 +28,7 @@ use Symfony\Component\OptionsResolver\OptionsResolver;
 
 class TimeType extends AbstractType
 {
-    private static $widgets = [
+    private const WIDGETS = [
         'text' => 'Symfony\Component\Form\Extension\Core\Type\TextType',
         'choice' => 'Symfony\Component\Form\Extension\Core\Type\ChoiceType',
     ];
@@ -169,7 +169,7 @@ class TimeType extends AbstractType
                 }
             }
 
-            $builder->add('hour', self::$widgets[$options['widget']], $hourOptions);
+            $builder->add('hour', self::WIDGETS[$options['widget']], $hourOptions);
 
             if ($options['with_minutes']) {
                 if ($emptyData instanceof \Closure) {
@@ -177,7 +177,7 @@ class TimeType extends AbstractType
                 } elseif (isset($emptyData['minute'])) {
                     $minuteOptions['empty_data'] = $emptyData['minute'];
                 }
-                $builder->add('minute', self::$widgets[$options['widget']], $minuteOptions);
+                $builder->add('minute', self::WIDGETS[$options['widget']], $minuteOptions);
             }
 
             if ($options['with_seconds']) {
@@ -186,7 +186,7 @@ class TimeType extends AbstractType
                 } elseif (isset($emptyData['second'])) {
                     $secondOptions['empty_data'] = $emptyData['second'];
                 }
-                $builder->add('second', self::$widgets[$options['widget']], $secondOptions);
+                $builder->add('second', self::WIDGETS[$options['widget']], $secondOptions);
             }
 
             $builder->addViewTransformer(new DateTimeToArrayTransformer($options['model_timezone'], $options['view_timezone'], $parts, 'text' === $options['widget'], $options['reference_date']));
diff --git a/src/Symfony/Component/Form/Extension/Core/Type/WeekType.php b/src/Symfony/Component/Form/Extension/Core/Type/WeekType.php
index bae115756a..fcc4f8b31e 100644
--- a/src/Symfony/Component/Form/Extension/Core/Type/WeekType.php
+++ b/src/Symfony/Component/Form/Extension/Core/Type/WeekType.php
@@ -23,7 +23,7 @@ use Symfony\Component\OptionsResolver\OptionsResolver;
 
 class WeekType extends AbstractType
 {
-    private static $widgets = [
+    private const WIDGETS = [
         'text' => IntegerType::class,
         'choice' => ChoiceType::class,
     ];
@@ -78,8 +78,8 @@ class WeekType extends AbstractType
                 }
             }
 
-            $builder->add('year', self::$widgets[$options['widget']], $yearOptions);
-            $builder->add('week', self::$widgets[$options['widget']], $weekOptions);
+            $builder->add('year', self::WIDGETS[$options['widget']], $yearOptions);
+            $builder->add('week', self::WIDGETS[$options['widget']], $weekOptions);
         }
     }
 
diff --git a/src/Symfony/Component/Form/NativeRequestHandler.php b/src/Symfony/Component/Form/NativeRequestHandler.php
index 2532256f2b..e65492466e 100644
--- a/src/Symfony/Component/Form/NativeRequestHandler.php
+++ b/src/Symfony/Component/Form/NativeRequestHandler.php
@@ -26,7 +26,7 @@ class NativeRequestHandler implements RequestHandlerInterface
     /**
      * The allowed keys of the $_FILES array.
      */
-    private static $fileKeys = [
+    private const FILE_KEYS = [
         'error',
         'name',
         'size',
@@ -201,12 +201,12 @@ class NativeRequestHandler implements RequestHandlerInterface
         $keys = array_keys($data);
         sort($keys);
 
-        if (self::$fileKeys !== $keys || !isset($data['name']) || !\is_array($data['name'])) {
+        if (self::FILE_KEYS !== $keys || !isset($data['name']) || !\is_array($data['name'])) {
             return $data;
         }
 
         $files = $data;
-        foreach (self::$fileKeys as $k) {
+        foreach (self::FILE_KEYS as $k) {
             unset($files[$k]);
         }
 
@@ -237,7 +237,7 @@ class NativeRequestHandler implements RequestHandlerInterface
         $keys = array_keys($data);
         sort($keys);
 
-        if (self::$fileKeys === $keys) {
+        if (self::FILE_KEYS === $keys) {
             if (\UPLOAD_ERR_NO_FILE === $data['error']) {
                 return null;
             }
diff --git a/src/Symfony/Component/HttpFoundation/Cookie.php b/src/Symfony/Component/HttpFoundation/Cookie.php
index 4a15bc997d..c2fba7f854 100644
--- a/src/Symfony/Component/HttpFoundation/Cookie.php
+++ b/src/Symfony/Component/HttpFoundation/Cookie.php
@@ -35,8 +35,8 @@ class Cookie
     private $secureDefault = false;
 
     private static $reservedCharsList = "=,; \t\r\n\v\f";
-    private static $reservedCharsFrom = ['=', ',', ';', ' ', "\t", "\r", "\n", "\v", "\f"];
-    private static $reservedCharsTo = ['%3D', '%2C', '%3B', '%20', '%09', '%0D', '%0A', '%0B', '%0C'];
+    private const RESERVED_CHARS_FROM = ['=', ',', ';', ' ', "\t", "\r", "\n", "\v", "\f"];
+    private const RESERVED_CHARS_TO = ['%3D', '%2C', '%3B', '%20', '%09', '%0D', '%0A', '%0B', '%0C'];
 
     /**
      * Creates cookie from raw header string.
@@ -149,7 +149,7 @@ class Cookie
         if ($this->isRaw()) {
             $str = $this->getName();
         } else {
-            $str = str_replace(self::$reservedCharsFrom, self::$reservedCharsTo, $this->getName());
+            $str = str_replace(self::RESERVED_CHARS_FROM, self::RESERVED_CHARS_TO, $this->getName());
         }
 
         $str .= '=';
diff --git a/src/Symfony/Component/HttpFoundation/FileBag.php b/src/Symfony/Component/HttpFoundation/FileBag.php
index 4674443459..bb187f7207 100644
--- a/src/Symfony/Component/HttpFoundation/FileBag.php
+++ b/src/Symfony/Component/HttpFoundation/FileBag.php
@@ -21,7 +21,7 @@ use Symfony\Component\HttpFoundation\File\UploadedFile;
  */
 class FileBag extends ParameterBag
 {
-    private static $fileKeys = ['error', 'name', 'size', 'tmp_name', 'type'];
+    private const FILE_KEYS = ['error', 'name', 'size', 'tmp_name', 'type'];
 
     /**
      * @param array|UploadedFile[] $parameters An array of HTTP files
@@ -80,7 +80,7 @@ class FileBag extends ParameterBag
             $keys = array_keys($file);
             sort($keys);
 
-            if ($keys == self::$fileKeys) {
+            if (self::FILE_KEYS == $keys) {
                 if (\UPLOAD_ERR_NO_FILE == $file['error']) {
                     $file = null;
                 } else {
@@ -118,12 +118,12 @@ class FileBag extends ParameterBag
         $keys = array_keys($data);
         sort($keys);
 
-        if (self::$fileKeys != $keys || !isset($data['name']) || !\is_array($data['name'])) {
+        if (self::FILE_KEYS != $keys || !isset($data['name']) || !\is_array($data['name'])) {
             return $data;
         }
 
         $files = $data;
-        foreach (self::$fileKeys as $k) {
+        foreach (self::FILE_KEYS as $k) {
             unset($files[$k]);
         }
 
diff --git a/src/Symfony/Component/HttpFoundation/Request.php b/src/Symfony/Component/HttpFoundation/Request.php
index 3c69f20ff0..4a9357aa54 100644
--- a/src/Symfony/Component/HttpFoundation/Request.php
+++ b/src/Symfony/Component/HttpFoundation/Request.php
@@ -209,7 +209,7 @@ class Request
 
     private static $trustedHeaderSet = -1;
 
-    private static $forwardedParams = [
+    private const FORWARDED_PARAMS = [
         self::HEADER_X_FORWARDED_FOR => 'for',
         self::HEADER_X_FORWARDED_HOST => 'host',
         self::HEADER_X_FORWARDED_PROTO => 'proto',
@@ -225,7 +225,7 @@ class Request
      * The other headers are non-standard, but widely used
      * by popular reverse proxies (like Apache mod_proxy or Amazon EC2).
      */
-    private static $trustedHeaders = [
+    private const TRUSTED_HEADERS = [
         self::HEADER_FORWARDED => 'FORWARDED',
         self::HEADER_X_FORWARDED_FOR => 'X_FORWARDED_FOR',
         self::HEADER_X_FORWARDED_HOST => 'X_FORWARDED_HOST',
@@ -1994,17 +1994,17 @@ class Request
         $clientValues = [];
         $forwardedValues = [];
 
-        if ((self::$trustedHeaderSet & $type) && $this->headers->has(self::$trustedHeaders[$type])) {
-            foreach (explode(',', $this->headers->get(self::$trustedHeaders[$type])) as $v) {
+        if ((self::$trustedHeaderSet & $type) && $this->headers->has(self::TRUSTED_HEADERS[$type])) {
+            foreach (explode(',', $this->headers->get(self::TRUSTED_HEADERS[$type])) as $v) {
                 $clientValues[] = (self::HEADER_X_FORWARDED_PORT === $type ? '0.0.0.0:' : '').trim($v);
             }
         }
 
-        if ((self::$trustedHeaderSet & self::HEADER_FORWARDED) && $this->headers->has(self::$trustedHeaders[self::HEADER_FORWARDED])) {
-            $forwarded = $this->headers->get(self::$trustedHeaders[self::HEADER_FORWARDED]);
+        if ((self::$trustedHeaderSet & self::HEADER_FORWARDED) && $this->headers->has(self::TRUSTED_HEADERS[self::HEADER_FORWARDED])) {
+            $forwarded = $this->headers->get(self::TRUSTED_HEADERS[self::HEADER_FORWARDED]);
             $parts = HeaderUtils::split($forwarded, ',;=');
             $forwardedValues = [];
-            $param = self::$forwardedParams[$type];
+            $param = self::FORWARDED_PARAMS[$type];
             foreach ($parts as $subParts) {
                 if (null === $v = HeaderUtils::combine($subParts)[$param] ?? null) {
                     continue;
@@ -2037,7 +2037,7 @@ class Request
         }
         $this->isForwardedValid = false;
 
-        throw new ConflictingHeadersException(sprintf('The request has both a trusted "%s" header and a trusted "%s" header, conflicting with each other. You should either configure your proxy to remove one of them, or configure your project to distrust the offending one.', self::$trustedHeaders[self::HEADER_FORWARDED], self::$trustedHeaders[$type]));
+        throw new ConflictingHeadersException(sprintf('The request has both a trusted "%s" header and a trusted "%s" header, conflicting with each other. You should either configure your proxy to remove one of them, or configure your project to distrust the offending one.', self::TRUSTED_HEADERS[self::HEADER_FORWARDED], self::TRUSTED_HEADERS[$type]));
     }
 
     private function normalizeAndFilterClientIps(array $clientIps, string $ip): array
diff --git a/src/Symfony/Component/HttpKernel/HttpCache/ResponseCacheStrategy.php b/src/Symfony/Component/HttpKernel/HttpCache/ResponseCacheStrategy.php
index c30fface60..1f09946846 100644
--- a/src/Symfony/Component/HttpKernel/HttpCache/ResponseCacheStrategy.php
+++ b/src/Symfony/Component/HttpKernel/HttpCache/ResponseCacheStrategy.php
@@ -27,12 +27,12 @@ class ResponseCacheStrategy implements ResponseCacheStrategyInterface
     /**
      * Cache-Control headers that are sent to the final response if they appear in ANY of the responses.
      */
-    private static $overrideDirectives = ['private', 'no-cache', 'no-store', 'no-transform', 'must-revalidate', 'proxy-revalidate'];
+    private const OVERRIDE_DIRECTIVES = ['private', 'no-cache', 'no-store', 'no-transform', 'must-revalidate', 'proxy-revalidate'];
 
     /**
      * Cache-Control headers that are sent to the final response if they appear in ALL of the responses.
      */
-    private static $inheritDirectives = ['public', 'immutable'];
+    private const INHERIT_DIRECTIVES = ['public', 'immutable'];
 
     private $embeddedResponses = 0;
     private $isNotCacheableResponseEmbedded = false;
@@ -60,13 +60,13 @@ class ResponseCacheStrategy implements ResponseCacheStrategyInterface
     {
         ++$this->embeddedResponses;
 
-        foreach (self::$overrideDirectives as $directive) {
+        foreach (self::OVERRIDE_DIRECTIVES as $directive) {
             if ($response->headers->hasCacheControlDirective($directive)) {
                 $this->flagDirectives[$directive] = true;
             }
         }
 
-        foreach (self::$inheritDirectives as $directive) {
+        foreach (self::INHERIT_DIRECTIVES as $directive) {
             if (false !== $this->flagDirectives[$directive]) {
                 $this->flagDirectives[$directive] = $response->headers->hasCacheControlDirective($directive);
             }
diff --git a/src/Symfony/Component/HttpKernel/Log/Logger.php b/src/Symfony/Component/HttpKernel/Log/Logger.php
index 0181817bdf..3922d2fe68 100644
--- a/src/Symfony/Component/HttpKernel/Log/Logger.php
+++ b/src/Symfony/Component/HttpKernel/Log/Logger.php
@@ -22,7 +22,7 @@ use Psr\Log\LogLevel;
  */
 class Logger extends AbstractLogger
 {
-    private static $levels = [
+    private const LEVELS = [
         LogLevel::DEBUG => 0,
         LogLevel::INFO => 1,
         LogLevel::NOTICE => 2,
@@ -52,11 +52,11 @@ class Logger extends AbstractLogger
             }
         }
 
-        if (!isset(self::$levels[$minLevel])) {
+        if (!isset(self::LEVELS[$minLevel])) {
             throw new InvalidArgumentException(sprintf('The log level "%s" does not exist.', $minLevel));
         }
 
-        $this->minLevelIndex = self::$levels[$minLevel];
+        $this->minLevelIndex = self::LEVELS[$minLevel];
         $this->formatter = $formatter ?: [$this, 'format'];
         if ($output && false === $this->handle = \is_resource($output) ? $output : @fopen($output, 'a')) {
             throw new InvalidArgumentException(sprintf('Unable to open "%s".', $output));
@@ -70,11 +70,11 @@ class Logger extends AbstractLogger
      */
     public function log($level, $message, array $context = [])
     {
-        if (!isset(self::$levels[$level])) {
+        if (!isset(self::LEVELS[$level])) {
             throw new InvalidArgumentException(sprintf('The log level "%s" does not exist.', $level));
         }
 
-        if (self::$levels[$level] < $this->minLevelIndex) {
+        if (self::LEVELS[$level] < $this->minLevelIndex) {
             return;
         }
 
diff --git a/src/Symfony/Component/Inflector/Inflector.php b/src/Symfony/Component/Inflector/Inflector.php
index 87cc6bd132..8d2323cc4b 100644
--- a/src/Symfony/Component/Inflector/Inflector.php
+++ b/src/Symfony/Component/Inflector/Inflector.php
@@ -23,7 +23,7 @@ final class Inflector
      *
      * @see http://english-zone.com/spelling/plurals.html
      */
-    private static $pluralMap = [
+    private const PLURAL_MAP = [
         // First entry: plural suffix, reversed
         // Second entry: length of plural suffix
         // Third entry: Whether the suffix may succeed a vocal
@@ -143,7 +143,7 @@ final class Inflector
      *
      * @see http://english-zone.com/spelling/plurals.html
      */
-    private static $singularMap = [
+    private const SINGULAR_MAP = [
         // First entry: singular suffix, reversed
         // Second entry: length of singular suffix
         // Third entry: Whether the suffix may succeed a vocal
@@ -309,7 +309,7 @@ final class Inflector
     /**
      * A list of words which should not be inflected, reversed.
      */
-    private static $uninflected = [
+    private const UNINFLECTED = [
         '',
         'atad',
         'reed',
@@ -346,7 +346,7 @@ final class Inflector
         $pluralLength = \strlen($lowerPluralRev);
 
         // Check if the word is one which is not inflected, return early if so
-        if (\in_array($lowerPluralRev, self::$uninflected, true)) {
+        if (\in_array($lowerPluralRev, self::UNINFLECTED, true)) {
             return $plural;
         }
 
@@ -354,7 +354,7 @@ final class Inflector
         // The inner loop $j iterates over the characters of the plural suffix
         // in the plural table to compare them with the characters of the actual
         // given plural suffix
-        foreach (self::$pluralMap as $map) {
+        foreach (self::PLURAL_MAP as $map) {
             $suffix = $map[0];
             $suffixLength = $map[1];
             $j = 0;
@@ -432,7 +432,7 @@ final class Inflector
         $singularLength = \strlen($lowerSingularRev);
 
         // Check if the word is one which is not inflected, return early if so
-        if (\in_array($lowerSingularRev, self::$uninflected, true)) {
+        if (\in_array($lowerSingularRev, self::UNINFLECTED, true)) {
             return $singular;
         }
 
@@ -440,7 +440,7 @@ final class Inflector
         // The inner loop $j iterates over the characters of the singular suffix
         // in the singular table to compare them with the characters of the actual
         // given singular suffix
-        foreach (self::$singularMap as $map) {
+        foreach (self::SINGULAR_MAP as $map) {
             $suffix = $map[0];
             $suffixLength = $map[1];
             $j = 0;
diff --git a/src/Symfony/Component/Intl/Data/Generator/CurrencyDataGenerator.php b/src/Symfony/Component/Intl/Data/Generator/CurrencyDataGenerator.php
index 2c9c31b58c..70e90b4277 100644
--- a/src/Symfony/Component/Intl/Data/Generator/CurrencyDataGenerator.php
+++ b/src/Symfony/Component/Intl/Data/Generator/CurrencyDataGenerator.php
@@ -25,7 +25,7 @@ use Symfony\Component\Intl\Data\Util\LocaleScanner;
  */
 class CurrencyDataGenerator extends AbstractDataGenerator
 {
-    private static $denylist = [
+    private const DENYLIST = [
         'XBA' => true, // European Composite Unit
         'XBB' => true, // European Monetary Unit
         'XBC' => true, // European Unit of Account (XBC)
@@ -133,7 +133,7 @@ class CurrencyDataGenerator extends AbstractDataGenerator
         $symbolNamePairs = iterator_to_array($rootBundle['Currencies']);
 
         // Remove unwanted currencies
-        $symbolNamePairs = array_diff_key($symbolNamePairs, self::$denylist);
+        $symbolNamePairs = array_diff_key($symbolNamePairs, self::DENYLIST);
 
         return $symbolNamePairs;
     }
diff --git a/src/Symfony/Component/Intl/Data/Generator/LanguageDataGenerator.php b/src/Symfony/Component/Intl/Data/Generator/LanguageDataGenerator.php
index 9546227b85..29ea558308 100644
--- a/src/Symfony/Component/Intl/Data/Generator/LanguageDataGenerator.php
+++ b/src/Symfony/Component/Intl/Data/Generator/LanguageDataGenerator.php
@@ -29,7 +29,7 @@ class LanguageDataGenerator extends AbstractDataGenerator
     /**
      * Source: https://iso639-3.sil.org/code_tables/639/data.
      */
-    private static $preferredAlpha2ToAlpha3Mapping = [
+    private const PREFERRED_ALPHA2_TO_ALPHA3_MAPPING = [
         'ak' => 'aka',
         'ar' => 'ara',
         'ay' => 'aym',
@@ -83,7 +83,7 @@ class LanguageDataGenerator extends AbstractDataGenerator
         'za' => 'zha',
         'zh' => 'zho',
     ];
-    private static $denylist = [
+    private const DENYLIST = [
         'root' => true, // Absolute root language
         'mul' => true, // Multiple languages
         'mis' => true, // Uncoded language
@@ -182,7 +182,7 @@ class LanguageDataGenerator extends AbstractDataGenerator
 
     private static function generateLanguageNames(ArrayAccessibleResourceBundle $localeBundle): array
     {
-        return array_diff_key(iterator_to_array($localeBundle['Languages']), self::$denylist);
+        return array_diff_key(iterator_to_array($localeBundle['Languages']), self::DENYLIST);
     }
 
     private function generateAlpha3Codes(array $languageCodes, ArrayAccessibleResourceBundle $metadataBundle): array
@@ -210,13 +210,13 @@ class LanguageDataGenerator extends AbstractDataGenerator
         foreach ($aliases as $alias => $data) {
             $language = $data['replacement'];
             if (2 === \strlen($language) && 3 === \strlen($alias) && 'overlong' === $data['reason']) {
-                if (isset(self::$preferredAlpha2ToAlpha3Mapping[$language])) {
+                if (isset(self::PREFERRED_ALPHA2_TO_ALPHA3_MAPPING[$language])) {
                     // Validate to prevent typos
-                    if (!isset($aliases[self::$preferredAlpha2ToAlpha3Mapping[$language]])) {
-                        throw new RuntimeException('The statically set three-letter mapping '.self::$preferredAlpha2ToAlpha3Mapping[$language].' for the language code '.$language.' seems to be invalid. Typo?');
+                    if (!isset($aliases[self::PREFERRED_ALPHA2_TO_ALPHA3_MAPPING[$language]])) {
+                        throw new RuntimeException('The statically set three-letter mapping '.self::PREFERRED_ALPHA2_TO_ALPHA3_MAPPING[$language].' for the language code '.$language.' seems to be invalid. Typo?');
                     }
 
-                    $alpha3 = self::$preferredAlpha2ToAlpha3Mapping[$language];
+                    $alpha3 = self::PREFERRED_ALPHA2_TO_ALPHA3_MAPPING[$language];
                     $alpha2 = $aliases[$alpha3]['replacement'];
 
                     if ($language !== $alpha2) {
@@ -225,7 +225,7 @@ class LanguageDataGenerator extends AbstractDataGenerator
 
                     $alpha2ToAlpha3[$language] = $alpha3;
                 } elseif (isset($alpha2ToAlpha3[$language])) {
-                    throw new RuntimeException('Multiple three-letter mappings exist for the language code '.$language.'. Please add one of them to the property $preferredAlpha2ToAlpha3Mapping.');
+                    throw new RuntimeException('Multiple three-letter mappings exist for the language code '.$language.'. Please add one of them to the const PREFERRED_ALPHA2_TO_ALPHA3_MAPPING.');
                 } else {
                     $alpha2ToAlpha3[$language] = $alias;
                 }
diff --git a/src/Symfony/Component/Intl/Data/Generator/RegionDataGenerator.php b/src/Symfony/Component/Intl/Data/Generator/RegionDataGenerator.php
index 146475e754..9d4d772d4e 100644
--- a/src/Symfony/Component/Intl/Data/Generator/RegionDataGenerator.php
+++ b/src/Symfony/Component/Intl/Data/Generator/RegionDataGenerator.php
@@ -31,7 +31,7 @@ class RegionDataGenerator extends AbstractDataGenerator
     /**
      * Source: https://en.wikipedia.org/wiki/List_of_ISO_3166_country_codes.
      */
-    private static $preferredAlpha2ToAlpha3Mapping = [
+    private const PREFERRED_ALPHA2_TO_ALPHA3_MAPPING = [
         'CD' => 'COD',
         'DE' => 'DEU',
         'FR' => 'FRA',
@@ -40,7 +40,7 @@ class RegionDataGenerator extends AbstractDataGenerator
         'YE' => 'YEM',
     ];
 
-    private static $denylist = [
+    private const DENYLIST = [
         // Exceptional reservations
         'AC' => true, // Ascension Island
         'CP' => true, // Clipperton Island
@@ -69,7 +69,7 @@ class RegionDataGenerator extends AbstractDataGenerator
 
     public static function isValidCountryCode($region)
     {
-        if (isset(self::$denylist[$region])) {
+        if (isset(self::DENYLIST[$region])) {
             return false;
         }
 
@@ -181,13 +181,13 @@ class RegionDataGenerator extends AbstractDataGenerator
         foreach ($aliases as $alias => $data) {
             $country = $data['replacement'];
             if (2 === \strlen($country) && 3 === \strlen($alias) && 'overlong' === $data['reason']) {
-                if (isset(self::$preferredAlpha2ToAlpha3Mapping[$country])) {
+                if (isset(self::PREFERRED_ALPHA2_TO_ALPHA3_MAPPING[$country])) {
                     // Validate to prevent typos
-                    if (!isset($aliases[self::$preferredAlpha2ToAlpha3Mapping[$country]])) {
-                        throw new RuntimeException('The statically set three-letter mapping '.self::$preferredAlpha2ToAlpha3Mapping[$country].' for the country code '.$country.' seems to be invalid. Typo?');
+                    if (!isset($aliases[self::PREFERRED_ALPHA2_TO_ALPHA3_MAPPING[$country]])) {
+                        throw new RuntimeException('The statically set three-letter mapping '.self::PREFERRED_ALPHA2_TO_ALPHA3_MAPPING[$country].' for the country code '.$country.' seems to be invalid. Typo?');
                     }
 
-                    $alpha3 = self::$preferredAlpha2ToAlpha3Mapping[$country];
+                    $alpha3 = self::PREFERRED_ALPHA2_TO_ALPHA3_MAPPING[$country];
                     $alpha2 = $aliases[$alpha3]['replacement'];
 
                     if ($country !== $alpha2) {
@@ -196,7 +196,7 @@ class RegionDataGenerator extends AbstractDataGenerator
 
                     $alpha2ToAlpha3[$country] = $alpha3;
                 } elseif (isset($alpha2ToAlpha3[$country])) {
-                    throw new RuntimeException('Multiple three-letter mappings exist for the country code '.$country.'. Please add one of them to the property $preferredAlpha2ToAlpha3Mapping.');
+                    throw new RuntimeException('Multiple three-letter mappings exist for the country code '.$country.'. Please add one of them to the const PREFERRED_ALPHA2_TO_ALPHA3_MAPPING.');
                 } elseif (isset($countries[$country]) && self::isValidCountryCode($alias)) {
                     $alpha2ToAlpha3[$country] = $alias;
                 }
diff --git a/src/Symfony/Component/Intl/Data/Generator/ScriptDataGenerator.php b/src/Symfony/Component/Intl/Data/Generator/ScriptDataGenerator.php
index be95b4b9fc..70e499e01d 100644
--- a/src/Symfony/Component/Intl/Data/Generator/ScriptDataGenerator.php
+++ b/src/Symfony/Component/Intl/Data/Generator/ScriptDataGenerator.php
@@ -24,7 +24,7 @@ use Symfony\Component\Intl\Data\Util\LocaleScanner;
  */
 class ScriptDataGenerator extends AbstractDataGenerator
 {
-    private static $denylist = [
+    private const DENYLIST = [
         'Zzzz' => true, // Unknown Script
     ];
 
@@ -69,7 +69,7 @@ class ScriptDataGenerator extends AbstractDataGenerator
         // isset() on \ResourceBundle returns true even if the value is null
         if (isset($localeBundle['Scripts']) && null !== $localeBundle['Scripts']) {
             $data = [
-                'Names' => array_diff_key(iterator_to_array($localeBundle['Scripts']), self::$denylist),
+                'Names' => array_diff_key(iterator_to_array($localeBundle['Scripts']), self::DENYLIST),
             ];
 
             $this->scriptCodes = array_merge($this->scriptCodes, array_keys($data['Names']));
diff --git a/src/Symfony/Component/Intl/Globals/IntlGlobals.php b/src/Symfony/Component/Intl/Globals/IntlGlobals.php
index 6113523e37..80022e6c04 100644
--- a/src/Symfony/Component/Intl/Globals/IntlGlobals.php
+++ b/src/Symfony/Component/Intl/Globals/IntlGlobals.php
@@ -38,7 +38,7 @@ abstract class IntlGlobals
     /**
      * All known error codes.
      */
-    private static $errorCodes = [
+    private const ERROR_CODES = [
         self::U_ZERO_ERROR => 'U_ZERO_ERROR',
         self::U_ILLEGAL_ARGUMENT_ERROR => 'U_ILLEGAL_ARGUMENT_ERROR',
         self::U_PARSE_ERROR => 'U_PARSE_ERROR',
@@ -61,7 +61,7 @@ abstract class IntlGlobals
      */
     public static function isFailure(int $errorCode): bool
     {
-        return isset(self::$errorCodes[$errorCode])
+        return isset(self::ERROR_CODES[$errorCode])
             && $errorCode > self::U_ZERO_ERROR;
     }
 
@@ -94,7 +94,7 @@ abstract class IntlGlobals
      */
     public static function getErrorName(int $code): string
     {
-        return self::$errorCodes[$code] ?? '[BOGUS UErrorCode]';
+        return self::ERROR_CODES[$code] ?? '[BOGUS UErrorCode]';
     }
 
     /**
@@ -107,11 +107,11 @@ abstract class IntlGlobals
      */
     public static function setError(int $code, string $message = '')
     {
-        if (!isset(self::$errorCodes[$code])) {
+        if (!isset(self::ERROR_CODES[$code])) {
             throw new \InvalidArgumentException(sprintf('No such error code: "%s".', $code));
         }
 
-        self::$errorMessage = $message ? sprintf('%s: %s', $message, self::$errorCodes[$code]) : self::$errorCodes[$code];
+        self::$errorMessage = $message ? sprintf('%s: %s', $message, self::ERROR_CODES[$code]) : self::ERROR_CODES[$code];
         self::$errorCode = $code;
     }
 }
diff --git a/src/Symfony/Component/Intl/NumberFormatter/NumberFormatter.php b/src/Symfony/Component/Intl/NumberFormatter/NumberFormatter.php
index 71447180cc..74e2f561c9 100644
--- a/src/Symfony/Component/Intl/NumberFormatter/NumberFormatter.php
+++ b/src/Symfony/Component/Intl/NumberFormatter/NumberFormatter.php
@@ -165,7 +165,7 @@ abstract class NumberFormatter
     /**
      * The supported styles to the constructor $styles argument.
      */
-    private static $supportedStyles = [
+    private const SUPPORTED_STYLES = [
         'CURRENCY' => self::CURRENCY,
         'DECIMAL' => self::DECIMAL,
     ];
@@ -173,7 +173,7 @@ abstract class NumberFormatter
     /**
      * Supported attributes to the setAttribute() $attr argument.
      */
-    private static $supportedAttributes = [
+    private const SUPPORTED_ATTRIBUTES = [
         'FRACTION_DIGITS' => self::FRACTION_DIGITS,
         'GROUPING_USED' => self::GROUPING_USED,
         'ROUNDING_MODE' => self::ROUNDING_MODE,
@@ -184,7 +184,7 @@ abstract class NumberFormatter
      * NumberFormatter::ROUNDING_MODE. NumberFormatter::ROUND_DOWN
      * and NumberFormatter::ROUND_UP does not have a PHP only equivalent.
      */
-    private static $roundingModes = [
+    private const ROUNDING_MODES = [
         'ROUND_HALFEVEN' => self::ROUND_HALFEVEN,
         'ROUND_HALFDOWN' => self::ROUND_HALFDOWN,
         'ROUND_HALFUP' => self::ROUND_HALFUP,
@@ -200,7 +200,7 @@ abstract class NumberFormatter
      *
      * @see https://php.net/round
      */
-    private static $phpRoundingMap = [
+    private const PHP_ROUNDING_MAP = [
         self::ROUND_HALFDOWN => \PHP_ROUND_HALF_DOWN,
         self::ROUND_HALFEVEN => \PHP_ROUND_HALF_EVEN,
         self::ROUND_HALFUP => \PHP_ROUND_HALF_UP,
@@ -211,7 +211,7 @@ abstract class NumberFormatter
      * PHP's round() function, but there's an equivalent. Keys are rounding
      * modes, values does not matter.
      */
-    private static $customRoundingList = [
+    private const CUSTOM_ROUNDING_LIST = [
         self::ROUND_CEILING => true,
         self::ROUND_FLOOR => true,
         self::ROUND_DOWN => true,
@@ -230,12 +230,12 @@ abstract class NumberFormatter
      */
     private static $int64Max = 9223372036854775807;
 
-    private static $enSymbols = [
+    private const EN_SYMBOLS = [
         self::DECIMAL => ['.', ',', ';', '%', '0', '#', '-', '+', '¤', '¤¤', '.', 'E', '‰', '*', '∞', 'NaN', '@', ','],
         self::CURRENCY => ['.', ',', ';', '%', '0', '#', '-', '+', '¤', '¤¤', '.', 'E', '‰', '*', '∞', 'NaN', '@', ','],
     ];
 
-    private static $enTextAttributes = [
+    private const EN_TEXT_ATTRIBUTES = [
         self::DECIMAL => ['', '', '-', '', ' ', 'XXX', ''],
         self::CURRENCY => ['¤', '', '-¤', '', ' ', 'XXX'],
     ];
@@ -263,8 +263,8 @@ abstract class NumberFormatter
             throw new MethodArgumentValueNotImplementedException(__METHOD__, 'locale', $locale, 'Only the locale "en" is supported');
         }
 
-        if (!\in_array($style, self::$supportedStyles)) {
-            $message = sprintf('The available styles are: %s.', implode(', ', array_keys(self::$supportedStyles)));
+        if (!\in_array($style, self::SUPPORTED_STYLES)) {
+            $message = sprintf('The available styles are: %s.', implode(', ', array_keys(self::SUPPORTED_STYLES)));
             throw new MethodArgumentValueNotImplementedException(__METHOD__, 'style', $style, $message);
         }
 
@@ -466,7 +466,7 @@ abstract class NumberFormatter
      */
     public function getSymbol($attr)
     {
-        return \array_key_exists($this->style, self::$enSymbols) && \array_key_exists($attr, self::$enSymbols[$this->style]) ? self::$enSymbols[$this->style][$attr] : false;
+        return \array_key_exists($this->style, self::EN_SYMBOLS) && \array_key_exists($attr, self::EN_SYMBOLS[$this->style]) ? self::EN_SYMBOLS[$this->style][$attr] : false;
     }
 
     /**
@@ -480,7 +480,7 @@ abstract class NumberFormatter
      */
     public function getTextAttribute($attr)
     {
-        return \array_key_exists($this->style, self::$enTextAttributes) && \array_key_exists($attr, self::$enTextAttributes[$this->style]) ? self::$enTextAttributes[$this->style][$attr] : false;
+        return \array_key_exists($this->style, self::EN_TEXT_ATTRIBUTES) && \array_key_exists($attr, self::EN_TEXT_ATTRIBUTES[$this->style]) ? self::EN_TEXT_ATTRIBUTES[$this->style][$attr] : false;
     }
 
     /**
@@ -579,29 +579,29 @@ abstract class NumberFormatter
     {
         $attr = (int) $attr;
 
-        if (!\in_array($attr, self::$supportedAttributes)) {
+        if (!\in_array($attr, self::SUPPORTED_ATTRIBUTES)) {
             $message = sprintf(
                 'The available attributes are: %s',
-                implode(', ', array_keys(self::$supportedAttributes))
+                implode(', ', array_keys(self::SUPPORTED_ATTRIBUTES))
             );
 
             throw new MethodArgumentValueNotImplementedException(__METHOD__, 'attr', $value, $message);
         }
 
-        if (self::$supportedAttributes['ROUNDING_MODE'] === $attr && $this->isInvalidRoundingMode($value)) {
+        if (self::SUPPORTED_ATTRIBUTES['ROUNDING_MODE'] === $attr && $this->isInvalidRoundingMode($value)) {
             $message = sprintf(
                 'The supported values for ROUNDING_MODE are: %s',
-                implode(', ', array_keys(self::$roundingModes))
+                implode(', ', array_keys(self::ROUNDING_MODES))
             );
 
             throw new MethodArgumentValueNotImplementedException(__METHOD__, 'attr', $value, $message);
         }
 
-        if (self::$supportedAttributes['GROUPING_USED'] === $attr) {
+        if (self::SUPPORTED_ATTRIBUTES['GROUPING_USED'] === $attr) {
             $value = $this->normalizeGroupingUsedValue($value);
         }
 
-        if (self::$supportedAttributes['FRACTION_DIGITS'] === $attr) {
+        if (self::SUPPORTED_ATTRIBUTES['FRACTION_DIGITS'] === $attr) {
             $value = $this->normalizeFractionDigitsValue($value);
             if ($value < 0) {
                 // ignore negative values but do not raise an error
@@ -718,9 +718,9 @@ abstract class NumberFormatter
         $precision = $this->getUninitializedPrecision($value, $precision);
 
         $roundingModeAttribute = $this->getAttribute(self::ROUNDING_MODE);
-        if (isset(self::$phpRoundingMap[$roundingModeAttribute])) {
-            $value = round($value, $precision, self::$phpRoundingMap[$roundingModeAttribute]);
-        } elseif (isset(self::$customRoundingList[$roundingModeAttribute])) {
+        if (isset(self::PHP_ROUNDING_MAP[$roundingModeAttribute])) {
+            $value = round($value, $precision, self::PHP_ROUNDING_MAP[$roundingModeAttribute]);
+        } elseif (isset(self::CUSTOM_ROUNDING_LIST[$roundingModeAttribute])) {
             $roundingCoef = 10 ** $precision;
             $value *= $roundingCoef;
             $value = (float) (string) $value;
@@ -846,7 +846,7 @@ abstract class NumberFormatter
      */
     private function isInvalidRoundingMode(int $value): bool
     {
-        if (\in_array($value, self::$roundingModes, true)) {
+        if (\in_array($value, self::ROUNDING_MODES, true)) {
             return false;
         }
 
diff --git a/src/Symfony/Component/Intl/Tests/CountriesTest.php b/src/Symfony/Component/Intl/Tests/CountriesTest.php
index 995072b0a4..f35932e5f3 100644
--- a/src/Symfony/Component/Intl/Tests/CountriesTest.php
+++ b/src/Symfony/Component/Intl/Tests/CountriesTest.php
@@ -21,7 +21,7 @@ class CountriesTest extends ResourceBundleTestCase
 {
     // The below arrays document the state of the ICU data bundled with this package.
 
-    private static $countries = [
+    private const COUNTRIES = [
         'AD',
         'AE',
         'AF',
@@ -273,7 +273,7 @@ class CountriesTest extends ResourceBundleTestCase
         'ZW',
     ];
 
-    private static $alpha2ToAlpha3 = [
+    private const ALPHA2_TO_ALPHA3 = [
         'AW' => 'ABW',
         'AF' => 'AFG',
         'AO' => 'AGO',
@@ -527,7 +527,7 @@ class CountriesTest extends ResourceBundleTestCase
 
     public function testGetCountryCodes()
     {
-        $this->assertSame(self::$countries, Countries::getCountryCodes());
+        $this->assertSame(self::COUNTRIES, Countries::getCountryCodes());
     }
 
     /**
@@ -539,7 +539,7 @@ class CountriesTest extends ResourceBundleTestCase
 
         sort($countries);
 
-        $this->assertSame(self::$countries, $countries);
+        $this->assertSame(self::COUNTRIES, $countries);
     }
 
     public function testGetNamesDefaultLocale()
@@ -604,20 +604,20 @@ class CountriesTest extends ResourceBundleTestCase
 
     public function testGetAlpha3Codes()
     {
-        $this->assertSame(self::$alpha2ToAlpha3, Countries::getAlpha3Codes());
+        $this->assertSame(self::ALPHA2_TO_ALPHA3, Countries::getAlpha3Codes());
     }
 
     public function testGetAlpha3Code()
     {
-        foreach (self::$countries as $country) {
-            $this->assertSame(self::$alpha2ToAlpha3[$country], Countries::getAlpha3Code($country));
+        foreach (self::COUNTRIES as $country) {
+            $this->assertSame(self::ALPHA2_TO_ALPHA3[$country], Countries::getAlpha3Code($country));
         }
     }
 
     public function testGetAlpha2Code()
     {
-        foreach (self::$countries as $alpha2Code) {
-            $alpha3Code = self::$alpha2ToAlpha3[$alpha2Code];
+        foreach (self::COUNTRIES as $alpha2Code) {
+            $alpha3Code = self::ALPHA2_TO_ALPHA3[$alpha2Code];
             $this->assertSame($alpha2Code, Countries::getAlpha2Code($alpha3Code));
         }
     }
@@ -639,7 +639,7 @@ class CountriesTest extends ResourceBundleTestCase
         $names = Countries::getNames($displayLocale);
 
         foreach ($names as $alpha2 => $name) {
-            $alpha3 = self::$alpha2ToAlpha3[$alpha2];
+            $alpha3 = self::ALPHA2_TO_ALPHA3[$alpha2];
             $this->assertSame($name, Countries::getAlpha3Name($alpha3, $displayLocale));
         }
     }
@@ -660,7 +660,7 @@ class CountriesTest extends ResourceBundleTestCase
 
         $alpha3Codes = array_keys($names);
         sort($alpha3Codes);
-        $this->assertSame(array_values(self::$alpha2ToAlpha3), $alpha3Codes);
+        $this->assertSame(array_values(self::ALPHA2_TO_ALPHA3), $alpha3Codes);
 
         $alpha2Names = Countries::getNames($displayLocale);
         $this->assertSame(array_values($alpha2Names), array_values($names));
diff --git a/src/Symfony/Component/Intl/Tests/CurrenciesTest.php b/src/Symfony/Component/Intl/Tests/CurrenciesTest.php
index 3edd7daa6b..58fc8fcb72 100644
--- a/src/Symfony/Component/Intl/Tests/CurrenciesTest.php
+++ b/src/Symfony/Component/Intl/Tests/CurrenciesTest.php
@@ -20,7 +20,7 @@ class CurrenciesTest extends ResourceBundleTestCase
 {
     // The below arrays document the state of the ICU data bundled with this package.
 
-    private static $currencies = [
+    private const CURRENCIES = [
         'ADP',
         'AED',
         'AFA',
@@ -313,7 +313,7 @@ class CurrenciesTest extends ResourceBundleTestCase
         'ZWR',
     ];
 
-    private static $alpha3ToNumeric = [
+    private const ALPHA3_TO_NUMERIC = [
         'AFA' => 4,
         'ALK' => 8,
         'ALL' => 8,
@@ -586,7 +586,7 @@ class CurrenciesTest extends ResourceBundleTestCase
 
     public function testGetCurrencyCodes()
     {
-        $this->assertSame(self::$currencies, Currencies::getCurrencyCodes());
+        $this->assertSame(self::CURRENCIES, Currencies::getCurrencyCodes());
     }
 
     /**
@@ -600,7 +600,7 @@ class CurrenciesTest extends ResourceBundleTestCase
 
         sort($keys);
 
-        $this->assertSame(self::$currencies, $keys);
+        $this->assertSame(self::CURRENCIES, $keys);
 
         // Names should be sorted
         $sortedNames = $names;
@@ -673,7 +673,7 @@ class CurrenciesTest extends ResourceBundleTestCase
     {
         return array_map(
             function ($currency) { return [$currency]; },
-            self::$currencies
+            self::CURRENCIES
         );
     }
 
@@ -700,7 +700,7 @@ class CurrenciesTest extends ResourceBundleTestCase
     {
         return array_map(
             function ($value) { return [$value]; },
-            array_keys(self::$alpha3ToNumeric)
+            array_keys(self::ALPHA3_TO_NUMERIC)
         );
     }
 
@@ -709,14 +709,14 @@ class CurrenciesTest extends ResourceBundleTestCase
      */
     public function testGetNumericCode($currency)
     {
-        $this->assertSame(self::$alpha3ToNumeric[$currency], Currencies::getNumericCode($currency));
+        $this->assertSame(self::ALPHA3_TO_NUMERIC[$currency], Currencies::getNumericCode($currency));
     }
 
     public function provideCurrenciesWithoutNumericEquivalent()
     {
         return array_map(
             function ($value) { return [$value]; },
-            array_diff(self::$currencies, array_keys(self::$alpha3ToNumeric))
+            array_diff(self::CURRENCIES, array_keys(self::ALPHA3_TO_NUMERIC))
         );
     }
 
@@ -790,7 +790,7 @@ class CurrenciesTest extends ResourceBundleTestCase
     {
         $numericToAlpha3 = [];
 
-        foreach (self::$alpha3ToNumeric as $alpha3 => $numeric) {
+        foreach (self::ALPHA3_TO_NUMERIC as $alpha3 => $numeric) {
             if (!isset($numericToAlpha3[$numeric])) {
                 $numericToAlpha3[$numeric] = [];
             }
diff --git a/src/Symfony/Component/Intl/Tests/Data/Bundle/Reader/BundleEntryReaderTest.php b/src/Symfony/Component/Intl/Tests/Data/Bundle/Reader/BundleEntryReaderTest.php
index ec159fb786..cf1239bf4f 100644
--- a/src/Symfony/Component/Intl/Tests/Data/Bundle/Reader/BundleEntryReaderTest.php
+++ b/src/Symfony/Component/Intl/Tests/Data/Bundle/Reader/BundleEntryReaderTest.php
@@ -33,7 +33,7 @@ class BundleEntryReaderTest extends TestCase
      */
     private $readerImpl;
 
-    private static $data = [
+    private const DATA = [
         'Entries' => [
             'Foo' => 'Bar',
             'Bar' => 'Baz',
@@ -42,7 +42,7 @@ class BundleEntryReaderTest extends TestCase
         'Version' => '2.0',
     ];
 
-    private static $fallbackData = [
+    private const FALLBACK_DATA = [
         'Entries' => [
             'Foo' => 'Foo',
             'Bam' => 'Lah',
@@ -51,7 +51,7 @@ class BundleEntryReaderTest extends TestCase
         'Version' => '1.0',
     ];
 
-    private static $mergedData = [
+    private const MERGED_DATA = [
         // no recursive merging -> too complicated
         'Entries' => [
             'Foo' => 'Bar',
@@ -73,9 +73,9 @@ class BundleEntryReaderTest extends TestCase
         $this->readerImpl->expects($this->once())
             ->method('read')
             ->with(self::RES_DIR, 'root')
-            ->willReturn(self::$data);
+            ->willReturn(self::DATA);
 
-        $this->assertSame(self::$data, $this->reader->read(self::RES_DIR, 'root'));
+        $this->assertSame(self::DATA, $this->reader->read(self::RES_DIR, 'root'));
     }
 
     public function testReadEntireDataFileIfNoIndicesGiven()
@@ -86,9 +86,9 @@ class BundleEntryReaderTest extends TestCase
                 [self::RES_DIR, 'en'],
                 [self::RES_DIR, 'root']
             )
-            ->willReturnOnConsecutiveCalls(self::$data, self::$fallbackData);
+            ->willReturnOnConsecutiveCalls(self::DATA, self::FALLBACK_DATA);
 
-        $this->assertSame(self::$mergedData, $this->reader->readEntry(self::RES_DIR, 'en', []));
+        $this->assertSame(self::MERGED_DATA, $this->reader->readEntry(self::RES_DIR, 'en', []));
     }
 
     public function testReadExistingEntry()
@@ -96,7 +96,7 @@ class BundleEntryReaderTest extends TestCase
         $this->readerImpl->expects($this->once())
             ->method('read')
             ->with(self::RES_DIR, 'root')
-            ->willReturn(self::$data);
+            ->willReturn(self::DATA);
 
         $this->assertSame('Bar', $this->reader->readEntry(self::RES_DIR, 'root', ['Entries', 'Foo']));
     }
@@ -107,7 +107,7 @@ class BundleEntryReaderTest extends TestCase
         $this->readerImpl->expects($this->once())
             ->method('read')
             ->with(self::RES_DIR, 'root')
-            ->willReturn(self::$data);
+            ->willReturn(self::DATA);
 
         $this->reader->readEntry(self::RES_DIR, 'root', ['Entries', 'NonExisting']);
     }
@@ -120,7 +120,7 @@ class BundleEntryReaderTest extends TestCase
                 [self::RES_DIR, 'en_GB'],
                 [self::RES_DIR, 'en']
             )
-            ->willReturnOnConsecutiveCalls(self::$data, self::$fallbackData);
+            ->willReturnOnConsecutiveCalls(self::DATA, self::FALLBACK_DATA);
 
         $this->assertSame('Lah', $this->reader->readEntry(self::RES_DIR, 'en_GB', ['Entries', 'Bam']));
     }
@@ -131,7 +131,7 @@ class BundleEntryReaderTest extends TestCase
         $this->readerImpl->expects($this->once())
             ->method('read')
             ->with(self::RES_DIR, 'en_GB')
-            ->willReturn(self::$data);
+            ->willReturn(self::DATA);
 
         $this->reader->readEntry(self::RES_DIR, 'en_GB', ['Entries', 'Bam'], false);
     }
@@ -146,7 +146,7 @@ class BundleEntryReaderTest extends TestCase
             )
             ->willReturnOnConsecutiveCalls(
                 $this->throwException(new ResourceBundleNotFoundException()),
-                self::$fallbackData
+                self::FALLBACK_DATA
             );
 
         $this->assertSame('Lah', $this->reader->readEntry(self::RES_DIR, 'en_GB', ['Entries', 'Bam']));
diff --git a/src/Symfony/Component/Intl/Tests/Data/Provider/AbstractDataProviderTest.php b/src/Symfony/Component/Intl/Tests/Data/Provider/AbstractDataProviderTest.php
index 1e12aafb1a..0086fbdffa 100644
--- a/src/Symfony/Component/Intl/Tests/Data/Provider/AbstractDataProviderTest.php
+++ b/src/Symfony/Component/Intl/Tests/Data/Provider/AbstractDataProviderTest.php
@@ -28,7 +28,7 @@ abstract class AbstractDataProviderTest extends TestCase
     // not loaded, because it is NOT possible to skip the execution of data
     // providers.
 
-    private static $locales = [
+    private const LOCALES = [
         'af',
         'af_NA',
         'af_ZA',
@@ -684,7 +684,7 @@ abstract class AbstractDataProviderTest extends TestCase
         'zu_ZA',
     ];
 
-    private static $localeAliases = [
+    private const LOCALE_ALIASES = [
         'az_AZ' => 'az_Latn_AZ',
         'bs_BA' => 'bs_Latn_BA',
         'en_NH' => 'en_VU',
@@ -766,12 +766,12 @@ abstract class AbstractDataProviderTest extends TestCase
 
     protected function getLocales()
     {
-        return self::$locales;
+        return self::LOCALES;
     }
 
     protected function getLocaleAliases()
     {
-        return self::$localeAliases;
+        return self::LOCALE_ALIASES;
     }
 
     protected function getRootLocales()
diff --git a/src/Symfony/Component/Intl/Tests/LanguagesTest.php b/src/Symfony/Component/Intl/Tests/LanguagesTest.php
index 9dfaf72609..154c21f98e 100644
--- a/src/Symfony/Component/Intl/Tests/LanguagesTest.php
+++ b/src/Symfony/Component/Intl/Tests/LanguagesTest.php
@@ -21,7 +21,7 @@ class LanguagesTest extends ResourceBundleTestCase
 {
     // The below arrays document the state of the ICU data bundled with this package.
 
-    private static $languages = [
+    private const LANGUAGES = [
         'aa',
         'ab',
         'ace',
@@ -618,7 +618,7 @@ class LanguagesTest extends ResourceBundleTestCase
         'zza',
     ];
 
-    private static $alpha3Codes = [
+    private const ALPHA3_CODES = [
         'aar',
         'abk',
         'ace',
@@ -1219,7 +1219,7 @@ class LanguagesTest extends ResourceBundleTestCase
         'zza',
     ];
 
-    private static $alpha2ToAlpha3 = [
+    private const ALPHA2_TO_ALPHA3 = [
         'aa' => 'aar',
         'ab' => 'abk',
         'af' => 'afr',
@@ -1402,7 +1402,7 @@ class LanguagesTest extends ResourceBundleTestCase
         'zu' => 'zul',
     ];
 
-    private static $alpha3ToAlpha2 = [
+    private const ALPHA3_TO_ALPHA2 = [
         'aar' => 'aa',
         'abk' => 'ab',
         'ave' => 'ae',
@@ -1590,7 +1590,7 @@ class LanguagesTest extends ResourceBundleTestCase
 
     public function testGetLanguageCodes()
     {
-        $this->assertEquals(self::$languages, Languages::getLanguageCodes());
+        $this->assertEquals(self::LANGUAGES, Languages::getLanguageCodes());
     }
 
     /**
@@ -1603,10 +1603,10 @@ class LanguagesTest extends ResourceBundleTestCase
         sort($languages);
 
         $this->assertNotEmpty($languages);
-        $this->assertEmpty(array_diff($languages, self::$languages));
+        $this->assertEmpty(array_diff($languages, self::LANGUAGES));
 
         foreach (Languages::getAlpha3Names($displayLocale) as $alpha3Code => $name) {
-            $alpha2Code = self::$alpha3ToAlpha2[$alpha3Code] ?? null;
+            $alpha2Code = self::ALPHA3_TO_ALPHA2[$alpha3Code] ?? null;
             if (null !== $alpha2Code) {
                 $this->assertSame($name, $names[$alpha2Code]);
             }
@@ -1665,7 +1665,7 @@ class LanguagesTest extends ResourceBundleTestCase
     {
         return array_map(
             function ($value) { return [$value]; },
-            array_keys(self::$alpha2ToAlpha3)
+            array_keys(self::ALPHA2_TO_ALPHA3)
         );
     }
 
@@ -1674,14 +1674,14 @@ class LanguagesTest extends ResourceBundleTestCase
      */
     public function testGetAlpha3Code($language)
     {
-        $this->assertSame(self::$alpha2ToAlpha3[$language], Languages::getAlpha3Code($language));
+        $this->assertSame(self::ALPHA2_TO_ALPHA3[$language], Languages::getAlpha3Code($language));
     }
 
     public function provideLanguagesWithoutAlpha3Equivalent()
     {
         return array_map(
             function ($value) { return [$value]; },
-            array_diff(self::$languages, array_keys(self::$alpha2ToAlpha3))
+            array_diff(self::LANGUAGES, array_keys(self::ALPHA2_TO_ALPHA3))
         );
     }
 
@@ -1708,14 +1708,14 @@ class LanguagesTest extends ResourceBundleTestCase
 
     public function testGetAlpha3Codes()
     {
-        $this->assertSame(self::$alpha3Codes, Languages::getAlpha3Codes());
+        $this->assertSame(self::ALPHA3_CODES, Languages::getAlpha3Codes());
     }
 
     public function provideLanguagesWithAlpha2Equivalent()
     {
         return array_map(
             function ($value) { return [$value]; },
-            array_keys(self::$alpha3ToAlpha2)
+            array_keys(self::ALPHA3_TO_ALPHA2)
         );
     }
 
@@ -1724,14 +1724,14 @@ class LanguagesTest extends ResourceBundleTestCase
      */
     public function testGetAlpha2Code($language)
     {
-        $this->assertSame(self::$alpha3ToAlpha2[$language], Languages::getAlpha2Code($language));
+        $this->assertSame(self::ALPHA3_TO_ALPHA2[$language], Languages::getAlpha2Code($language));
     }
 
     public function provideLanguagesWithoutAlpha2Equivalent()
     {
         return array_map(
             function ($value) { return [$value]; },
-            array_diff(self::$alpha3Codes, array_keys(self::$alpha3ToAlpha2))
+            array_diff(self::ALPHA3_CODES, array_keys(self::ALPHA3_TO_ALPHA2))
         );
     }
 
@@ -1786,10 +1786,10 @@ class LanguagesTest extends ResourceBundleTestCase
         sort($languages);
 
         $this->assertNotEmpty($languages);
-        $this->assertEmpty(array_diff($languages, self::$alpha3Codes));
+        $this->assertEmpty(array_diff($languages, self::ALPHA3_CODES));
 
         foreach (Languages::getNames($displayLocale) as $alpha2Code => $name) {
-            $alpha3Code = self::$alpha2ToAlpha3[$alpha2Code] ?? (3 === \strlen($alpha2Code) ? $alpha2Code : null);
+            $alpha3Code = self::ALPHA2_TO_ALPHA3[$alpha2Code] ?? (3 === \strlen($alpha2Code) ? $alpha2Code : null);
             if (null !== $alpha3Code) {
                 $this->assertSame($name, $names[$alpha3Code]);
             }
diff --git a/src/Symfony/Component/Intl/Tests/NumberFormatter/AbstractNumberFormatterTest.php b/src/Symfony/Component/Intl/Tests/NumberFormatter/AbstractNumberFormatterTest.php
index 44a7d27269..f392b3da50 100644
--- a/src/Symfony/Component/Intl/Tests/NumberFormatter/AbstractNumberFormatterTest.php
+++ b/src/Symfony/Component/Intl/Tests/NumberFormatter/AbstractNumberFormatterTest.php
@@ -614,8 +614,7 @@ abstract class AbstractNumberFormatterTest extends TestCase
         $decimalFormatter = $this->getNumberFormatter('en', NumberFormatter::DECIMAL);
         $currencyFormatter = $this->getNumberFormatter('en', NumberFormatter::CURRENCY);
 
-        $r = new \ReflectionProperty(NumberFormatter::class, 'enSymbols');
-        $r->setAccessible(true);
+        $r = new \ReflectionClassConstant(NumberFormatter::class, 'EN_SYMBOLS');
         $expected = $r->getValue();
 
         for ($i = 0; $i <= 17; ++$i) {
@@ -631,8 +630,7 @@ abstract class AbstractNumberFormatterTest extends TestCase
         $decimalFormatter = $this->getNumberFormatter('en', NumberFormatter::DECIMAL);
         $currencyFormatter = $this->getNumberFormatter('en', NumberFormatter::CURRENCY);
 
-        $r = new \ReflectionProperty(NumberFormatter::class, 'enTextAttributes');
-        $r->setAccessible(true);
+        $r = new \ReflectionClassConstant(NumberFormatter::class, 'EN_TEXT_ATTRIBUTES');
         $expected = $r->getValue();
 
         for ($i = 0; $i <= 5; ++$i) {
diff --git a/src/Symfony/Component/Intl/Tests/ResourceBundleTestCase.php b/src/Symfony/Component/Intl/Tests/ResourceBundleTestCase.php
index e0d11542e4..5b0096aab6 100644
--- a/src/Symfony/Component/Intl/Tests/ResourceBundleTestCase.php
+++ b/src/Symfony/Component/Intl/Tests/ResourceBundleTestCase.php
@@ -21,7 +21,7 @@ abstract class ResourceBundleTestCase extends TestCase
     // not loaded, because it is NOT possible to skip the execution of data
     // providers.
 
-    private static $locales = [
+    private const LOCALES = [
         'af',
         'af_NA',
         'af_ZA',
@@ -677,7 +677,7 @@ abstract class ResourceBundleTestCase extends TestCase
         'zu_ZA',
     ];
 
-    private static $localeAliases = [
+    private const LOCALE_ALIASES = [
         'az_AZ' => 'az_Latn_AZ',
         'bs_BA' => 'bs_Latn_BA',
         'en_NH' => 'en_VU',
@@ -759,12 +759,12 @@ abstract class ResourceBundleTestCase extends TestCase
 
     protected function getLocales()
     {
-        return self::$locales;
+        return self::LOCALES;
     }
 
     protected function getLocaleAliases()
     {
-        return self::$localeAliases;
+        return self::LOCALE_ALIASES;
     }
 
     protected function getRootLocales()
diff --git a/src/Symfony/Component/Intl/Tests/TimezonesTest.php b/src/Symfony/Component/Intl/Tests/TimezonesTest.php
index f02fabe8e6..025a9cbba5 100644
--- a/src/Symfony/Component/Intl/Tests/TimezonesTest.php
+++ b/src/Symfony/Component/Intl/Tests/TimezonesTest.php
@@ -22,7 +22,7 @@ class TimezonesTest extends ResourceBundleTestCase
 {
     // The below arrays document the state of the ICU data bundled with this package.
 
-    private static $zones = [
+    private const ZONES = [
         'Africa/Abidjan',
         'Africa/Accra',
         'Africa/Addis_Ababa',
@@ -458,7 +458,7 @@ class TimezonesTest extends ResourceBundleTestCase
         'Pacific/Wake',
         'Pacific/Wallis',
     ];
-    private static $zonesNoCountry = [
+    private const ZONES_NO_COUNTRY = [
         'Antarctica/Troll',
         'CST6CDT',
         'EST5EDT',
@@ -470,7 +470,7 @@ class TimezonesTest extends ResourceBundleTestCase
 
     public function testGetIds()
     {
-        $this->assertEquals(self::$zones, Timezones::getIds());
+        $this->assertEquals(self::ZONES, Timezones::getIds());
     }
 
     /**
@@ -483,7 +483,7 @@ class TimezonesTest extends ResourceBundleTestCase
         sort($zones);
 
         $this->assertNotEmpty($zones);
-        $this->assertEmpty(array_diff($zones, self::$zones));
+        $this->assertEmpty(array_diff($zones, self::ZONES));
     }
 
     public function testGetNamesDefaultLocale()
@@ -631,7 +631,7 @@ class TimezonesTest extends ResourceBundleTestCase
 
             $this->addToAssertionCount(1);
         } catch (MissingResourceException $e) {
-            if (\in_array($timezone, self::$zonesNoCountry, true)) {
+            if (\in_array($timezone, self::ZONES_NO_COUNTRY, true)) {
                 $this->markTestSkipped();
             } else {
                 $this->fail();
@@ -643,7 +643,7 @@ class TimezonesTest extends ResourceBundleTestCase
     {
         return array_map(function ($timezone) {
             return [$timezone];
-        }, self::$zones);
+        }, self::ZONES);
     }
 
     /**
diff --git a/src/Symfony/Component/Ldap/Ldap.php b/src/Symfony/Component/Ldap/Ldap.php
index 7c8fe839de..607322afef 100644
--- a/src/Symfony/Component/Ldap/Ldap.php
+++ b/src/Symfony/Component/Ldap/Ldap.php
@@ -23,7 +23,7 @@ final class Ldap implements LdapInterface
 {
     private $adapter;
 
-    private static $adapterMap = [
+    private const ADAPTER_MAP = [
         'ext_ldap' => 'Symfony\Component\Ldap\Adapter\ExtLdap\Adapter',
     ];
 
@@ -74,11 +74,11 @@ final class Ldap implements LdapInterface
      */
     public static function create($adapter, array $config = []): self
     {
-        if (!isset(self::$adapterMap[$adapter])) {
-            throw new DriverNotFoundException(sprintf('Adapter "%s" not found. You should use one of: "%s".', $adapter, implode('", "', self::$adapterMap)));
+        if (!isset(self::ADAPTER_MAP[$adapter])) {
+            throw new DriverNotFoundException(sprintf('Adapter "%s" not found. You should use one of: "%s".', $adapter, implode('", "', self::ADAPTER_MAP)));
         }
 
-        $class = self::$adapterMap[$adapter];
+        $class = self::ADAPTER_MAP[$adapter];
 
         return new self(new $class($config));
     }
diff --git a/src/Symfony/Component/Mime/Encoder/QpEncoder.php b/src/Symfony/Component/Mime/Encoder/QpEncoder.php
index 4f249e069e..b861af2322 100644
--- a/src/Symfony/Component/Mime/Encoder/QpEncoder.php
+++ b/src/Symfony/Component/Mime/Encoder/QpEncoder.php
@@ -21,7 +21,7 @@ class QpEncoder implements EncoderInterface
     /**
      * Pre-computed QP for HUGE optimization.
      */
-    private static $qpMap = [
+    private const QP_MAP = [
         0 => '=00', 1 => '=01', 2 => '=02', 3 => '=03', 4 => '=04',
         5 => '=05', 6 => '=06', 7 => '=07', 8 => '=08', 9 => '=09',
         10 => '=0A', 11 => '=0B', 12 => '=0C', 13 => '=0D', 14 => '=0E',
@@ -170,7 +170,7 @@ class QpEncoder implements EncoderInterface
                 $ret .= $this->safeMap[$b];
                 ++$size;
             } else {
-                $ret .= self::$qpMap[$b];
+                $ret .= self::QP_MAP[$b];
                 $size += 3;
             }
         }
@@ -187,7 +187,7 @@ class QpEncoder implements EncoderInterface
         switch ($end = \ord(substr($string, -1))) {
             case 0x09:
             case 0x20:
-                $string = substr_replace($string, self::$qpMap[$end], -1);
+                $string = substr_replace($string, self::QP_MAP[$end], -1);
         }
 
         return $string;
diff --git a/src/Symfony/Component/Mime/Header/Headers.php b/src/Symfony/Component/Mime/Header/Headers.php
index 9de506e36e..c6e4c8eaaf 100644
--- a/src/Symfony/Component/Mime/Header/Headers.php
+++ b/src/Symfony/Component/Mime/Header/Headers.php
@@ -21,7 +21,7 @@ use Symfony\Component\Mime\Exception\LogicException;
  */
 final class Headers
 {
-    private static $uniqueHeaders = [
+    private const UNIQUE_HEADERS = [
         'date', 'from', 'sender', 'reply-to', 'to', 'cc', 'bcc',
         'message-id', 'in-reply-to', 'references', 'subject',
     ];
@@ -153,7 +153,7 @@ final class Headers
             throw new LogicException(sprintf('The "%s" header must be an instance of "%s" (got "%s").', $header->getName(), $map[$name], \get_class($header)));
         }
 
-        if (\in_array($name, self::$uniqueHeaders, true) && isset($this->headers[$name]) && \count($this->headers[$name]) > 0) {
+        if (\in_array($name, self::UNIQUE_HEADERS, true) && isset($this->headers[$name]) && \count($this->headers[$name]) > 0) {
             throw new LogicException(sprintf('Impossible to set header "%s" as it\'s already defined and must be unique.', $header->getName()));
         }
 
@@ -201,7 +201,7 @@ final class Headers
 
     public static function isUniqueHeader(string $name): bool
     {
-        return \in_array($name, self::$uniqueHeaders, true);
+        return \in_array($name, self::UNIQUE_HEADERS, true);
     }
 
     public function toString(): string
diff --git a/src/Symfony/Component/Mime/MimeTypes.php b/src/Symfony/Component/Mime/MimeTypes.php
index 5de599ca9a..e2b5bf4354 100644
--- a/src/Symfony/Component/Mime/MimeTypes.php
+++ b/src/Symfony/Component/Mime/MimeTypes.php
@@ -87,7 +87,7 @@ final class MimeTypes implements MimeTypesInterface
             $extensions = $this->extensions[$mimeType] ?? $this->extensions[$lcMimeType = strtolower($mimeType)] ?? null;
         }
 
-        return $extensions ?? self::$map[$mimeType] ?? self::$map[$lcMimeType ?? strtolower($mimeType)] ?? [];
+        return $extensions ?? self::MAP[$mimeType] ?? self::MAP[$lcMimeType ?? strtolower($mimeType)] ?? [];
     }
 
     /**
@@ -99,7 +99,7 @@ final class MimeTypes implements MimeTypesInterface
             $mimeTypes = $this->mimeTypes[$ext] ?? $this->mimeTypes[$lcExt = strtolower($ext)] ?? null;
         }
 
-        return $mimeTypes ?? self::$reverseMap[$ext] ?? self::$reverseMap[$lcExt ?? strtolower($ext)] ?? [];
+        return $mimeTypes ?? self::REVERSE_MAP[$ext] ?? self::REVERSE_MAP[$lcExt ?? strtolower($ext)] ?? [];
     }
 
     /**
@@ -150,7 +150,7 @@ final class MimeTypes implements MimeTypesInterface
      *
      * @see Resources/bin/update_mime_types.php
      */
-    private static $map = [
+    private const MAP = [
         'application/acrobat' => ['pdf'],
         'application/andrew-inset' => ['ez'],
         'application/annodex' => ['anx'],
@@ -1611,7 +1611,7 @@ final class MimeTypes implements MimeTypesInterface
         'zz-application/zz-winassoc-xls' => ['xls', 'xlc', 'xll', 'xlm', 'xlw', 'xla', 'xlt', 'xld'],
     ];
 
-    private static $reverseMap = [
+    private const REVERSE_MAP = [
         '32x' => ['application/x-genesis-32x-rom'],
         '3dml' => ['text/vnd.in3d.3dml'],
         '3ds' => ['image/x-3ds'],
diff --git a/src/Symfony/Component/OptionsResolver/OptionsResolver.php b/src/Symfony/Component/OptionsResolver/OptionsResolver.php
index 6567a59608..f63efbddf4 100644
--- a/src/Symfony/Component/OptionsResolver/OptionsResolver.php
+++ b/src/Symfony/Component/OptionsResolver/OptionsResolver.php
@@ -105,7 +105,7 @@ class OptionsResolver implements Options
 
     private $parentsOptions = [];
 
-    private static $typeAliases = [
+    private const TYPE_ALIASES = [
         'boolean' => 'bool',
         'integer' => 'int',
         'double' => 'float',
@@ -926,7 +926,7 @@ class OptionsResolver implements Options
             $invalidTypes = [];
 
             foreach ($this->allowedTypes[$option] as $type) {
-                $type = self::$typeAliases[$type] ?? $type;
+                $type = self::TYPE_ALIASES[$type] ?? $type;
 
                 if ($valid = $this->verifyTypes($type, $value, $invalidTypes)) {
                     break;
@@ -938,7 +938,7 @@ class OptionsResolver implements Options
                 $fmtAllowedTypes = implode('" or "', $this->allowedTypes[$option]);
                 $fmtProvidedTypes = implode('|', array_keys($invalidTypes));
                 $allowedContainsArrayType = \count(array_filter($this->allowedTypes[$option], static function ($item) {
-                    return '[]' === substr(self::$typeAliases[$item] ?? $item, -2);
+                    return '[]' === substr(self::TYPE_ALIASES[$item] ?? $item, -2);
                 })) > 0;
 
                 if (\is_array($value) && $allowedContainsArrayType) {
diff --git a/src/Symfony/Component/PropertyAccess/PropertyAccessor.php b/src/Symfony/Component/PropertyAccess/PropertyAccessor.php
index b442c3ae53..197d4fc6d3 100644
--- a/src/Symfony/Component/PropertyAccess/PropertyAccessor.php
+++ b/src/Symfony/Component/PropertyAccess/PropertyAccessor.php
@@ -66,7 +66,7 @@ class PropertyAccessor implements PropertyAccessorInterface
     private $propertyPathCache = [];
     private $readPropertyCache = [];
     private $writePropertyCache = [];
-    private static $resultProto = [self::VALUE => null];
+    private const RESULT_PROTO = [self::VALUE => null];
 
     /**
      * Should not be used by application code. Use
@@ -355,7 +355,7 @@ class PropertyAccessor implements PropertyAccessorInterface
             throw new NoSuchIndexException(sprintf('Cannot read index "%s" from object of type "%s" because it doesn\'t implement \ArrayAccess.', $index, \get_class($zval[self::VALUE])));
         }
 
-        $result = self::$resultProto;
+        $result = self::RESULT_PROTO;
 
         if (isset($zval[self::VALUE][$index])) {
             $result[self::VALUE] = $zval[self::VALUE][$index];
@@ -383,7 +383,7 @@ class PropertyAccessor implements PropertyAccessorInterface
             throw new NoSuchPropertyException(sprintf('Cannot read property "%s" from an array. Maybe you intended to write the property path as "[%1$s]" instead.', $property));
         }
 
-        $result = self::$resultProto;
+        $result = self::RESULT_PROTO;
         $object = $zval[self::VALUE];
         $access = $this->getReadAccessInfo(\get_class($object), $property);
 
diff --git a/src/Symfony/Component/Routing/Loader/YamlFileLoader.php b/src/Symfony/Component/Routing/Loader/YamlFileLoader.php
index c72d588f73..a4edb8869c 100644
--- a/src/Symfony/Component/Routing/Loader/YamlFileLoader.php
+++ b/src/Symfony/Component/Routing/Loader/YamlFileLoader.php
@@ -28,7 +28,7 @@ use Symfony\Component\Yaml\Yaml;
  */
 class YamlFileLoader extends FileLoader
 {
-    private static $availableKeys = [
+    private const AVAILABLE_KEYS = [
         'resource', 'type', 'prefix', 'path', 'host', 'schemes', 'methods', 'defaults', 'requirements', 'options', 'condition', 'controller', 'name_prefix', 'trailing_slash_on_root', 'locale', 'format', 'utf8', 'exclude',
     ];
     private $yamlParser;
@@ -269,8 +269,8 @@ class YamlFileLoader extends FileLoader
         if (!\is_array($config)) {
             throw new \InvalidArgumentException(sprintf('The definition of "%s" in "%s" must be a YAML array.', $name, $path));
         }
-        if ($extraKeys = array_diff(array_keys($config), self::$availableKeys)) {
-            throw new \InvalidArgumentException(sprintf('The routing file "%s" contains unsupported keys for "%s": "%s". Expected one of: "%s".', $path, $name, implode('", "', $extraKeys), implode('", "', self::$availableKeys)));
+        if ($extraKeys = array_diff(array_keys($config), self::AVAILABLE_KEYS)) {
+            throw new \InvalidArgumentException(sprintf('The routing file "%s" contains unsupported keys for "%s": "%s". Expected one of: "%s".', $path, $name, implode('", "', $extraKeys), implode('", "', self::AVAILABLE_KEYS)));
         }
         if (isset($config['resource']) && isset($config['path'])) {
             throw new \InvalidArgumentException(sprintf('The routing file "%s" must not specify both the "resource" key and the "path" key for "%s". Choose between an import and a route definition.', $path, $name));
diff --git a/src/Symfony/Component/Serializer/Normalizer/DataUriNormalizer.php b/src/Symfony/Component/Serializer/Normalizer/DataUriNormalizer.php
index 4646d6ce0d..b1643fb4d0 100644
--- a/src/Symfony/Component/Serializer/Normalizer/DataUriNormalizer.php
+++ b/src/Symfony/Component/Serializer/Normalizer/DataUriNormalizer.php
@@ -27,7 +27,7 @@ use Symfony\Component\Serializer\Exception\NotNormalizableValueException;
  */
 class DataUriNormalizer implements NormalizerInterface, DenormalizerInterface, CacheableSupportsMethodInterface
 {
-    private static $supportedTypes = [
+    private const SUPPORTED_TYPES = [
         \SplFileInfo::class => true,
         \SplFileObject::class => true,
         File::class => true,
@@ -134,7 +134,7 @@ class DataUriNormalizer implements NormalizerInterface, DenormalizerInterface, C
      */
     public function supportsDenormalization($data, $type, $format = null)
     {
-        return isset(self::$supportedTypes[$type]);
+        return isset(self::SUPPORTED_TYPES[$type]);
     }
 
     /**
diff --git a/src/Symfony/Component/Serializer/Normalizer/DateTimeNormalizer.php b/src/Symfony/Component/Serializer/Normalizer/DateTimeNormalizer.php
index fb28dff331..8bdfc977ef 100644
--- a/src/Symfony/Component/Serializer/Normalizer/DateTimeNormalizer.php
+++ b/src/Symfony/Component/Serializer/Normalizer/DateTimeNormalizer.php
@@ -27,7 +27,7 @@ class DateTimeNormalizer implements NormalizerInterface, DenormalizerInterface,
 
     private $defaultContext;
 
-    private static $supportedTypes = [
+    private const SUPPORTED_TYPES = [
         \DateTimeInterface::class => true,
         \DateTimeImmutable::class => true,
         \DateTime::class => true,
@@ -125,7 +125,7 @@ class DateTimeNormalizer implements NormalizerInterface, DenormalizerInterface,
      */
     public function supportsDenormalization($data, $type, $format = null)
     {
-        return isset(self::$supportedTypes[$type]);
+        return isset(self::SUPPORTED_TYPES[$type]);
     }
 
     /**
diff --git a/src/Symfony/Component/Validator/Constraints/EmailValidator.php b/src/Symfony/Component/Validator/Constraints/EmailValidator.php
index 4642f41b67..cbe8f52a44 100644
--- a/src/Symfony/Component/Validator/Constraints/EmailValidator.php
+++ b/src/Symfony/Component/Validator/Constraints/EmailValidator.php
@@ -35,7 +35,7 @@ class EmailValidator extends ConstraintValidator
      */
     public const PATTERN_LOOSE = '/^.+\@\S+\.\S+$/';
 
-    private static $emailPatterns = [
+    private const EMAIL_PATTERNS = [
         Email::VALIDATION_MODE_LOOSE => self::PATTERN_LOOSE,
         Email::VALIDATION_MODE_HTML5 => self::PATTERN_HTML5,
     ];
@@ -129,7 +129,7 @@ class EmailValidator extends ConstraintValidator
 
                 return;
             }
-        } elseif (!preg_match(self::$emailPatterns[$constraint->mode], $value)) {
+        } elseif (!preg_match(self::EMAIL_PATTERNS[$constraint->mode], $value)) {
             $this->context->buildViolation($constraint->message)
                 ->setParameter('{{ value }}', $this->formatValue($value))
                 ->setCode(Email::INVALID_FORMAT_ERROR)
diff --git a/src/Symfony/Component/Validator/Constraints/FileValidator.php b/src/Symfony/Component/Validator/Constraints/FileValidator.php
index 9cc68346a5..3a4195ffbe 100644
--- a/src/Symfony/Component/Validator/Constraints/FileValidator.php
+++ b/src/Symfony/Component/Validator/Constraints/FileValidator.php
@@ -30,7 +30,7 @@ class FileValidator extends ConstraintValidator
     public const KIB_BYTES = 1024;
     public const MIB_BYTES = 1048576;
 
-    private static $suffices = [
+    private const SUFFICES = [
         1 => 'bytes',
         self::KB_BYTES => 'kB',
         self::MB_BYTES => 'MB',
@@ -247,6 +247,6 @@ class FileValidator extends ConstraintValidator
             $sizeAsString = (string) round($size / $coef, 2);
         }
 
-        return [$sizeAsString, $limitAsString, self::$suffices[$coef]];
+        return [$sizeAsString, $limitAsString, self::SUFFICES[$coef]];
     }
 }
diff --git a/src/Symfony/Component/Validator/Constraints/IbanValidator.php b/src/Symfony/Component/Validator/Constraints/IbanValidator.php
index 27194ded21..0f39a3a9ce 100644
--- a/src/Symfony/Component/Validator/Constraints/IbanValidator.php
+++ b/src/Symfony/Component/Validator/Constraints/IbanValidator.php
@@ -36,7 +36,7 @@ class IbanValidator extends ConstraintValidator
      *
      * @see https://www.swift.com/sites/default/files/resources/iban_registry.pdf
      */
-    private static $formats = [
+    private const FORMATS = [
         'AD' => 'AD\d{2}\d{4}\d{4}[\dA-Z]{12}', // Andorra
         'AE' => 'AE\d{2}\d{3}\d{16}', // United Arab Emirates
         'AL' => 'AL\d{2}\d{8}[\dA-Z]{16}', // Albania
@@ -182,7 +182,7 @@ class IbanValidator extends ConstraintValidator
         }
 
         // ...have a format available
-        if (!\array_key_exists($countryCode, self::$formats)) {
+        if (!\array_key_exists($countryCode, self::FORMATS)) {
             $this->context->buildViolation($constraint->message)
                 ->setParameter('{{ value }}', $this->formatValue($value))
                 ->setCode(Iban::NOT_SUPPORTED_COUNTRY_CODE_ERROR)
@@ -192,7 +192,7 @@ class IbanValidator extends ConstraintValidator
         }
 
         // ...and have a valid format
-        if (!preg_match('/^'.self::$formats[$countryCode].'$/', $canonicalized)
+        if (!preg_match('/^'.self::FORMATS[$countryCode].'$/', $canonicalized)
         ) {
             $this->context->buildViolation($constraint->message)
                 ->setParameter('{{ value }}', $this->formatValue($value))
diff --git a/src/Symfony/Component/VarDumper/Caster/AmqpCaster.php b/src/Symfony/Component/VarDumper/Caster/AmqpCaster.php
index b81043bf11..60045ff7b0 100644
--- a/src/Symfony/Component/VarDumper/Caster/AmqpCaster.php
+++ b/src/Symfony/Component/VarDumper/Caster/AmqpCaster.php
@@ -22,7 +22,7 @@ use Symfony\Component\VarDumper\Cloner\Stub;
  */
 class AmqpCaster
 {
-    private static $flags = [
+    private const FLAGS = [
         \AMQP_DURABLE => 'AMQP_DURABLE',
         \AMQP_PASSIVE => 'AMQP_PASSIVE',
         \AMQP_EXCLUSIVE => 'AMQP_EXCLUSIVE',
@@ -39,7 +39,7 @@ class AmqpCaster
         \AMQP_REQUEUE => 'AMQP_REQUEUE',
     ];
 
-    private static $exchangeTypes = [
+    private const EXCHANGE_TYPES = [
         \AMQP_EX_TYPE_DIRECT => 'AMQP_EX_TYPE_DIRECT',
         \AMQP_EX_TYPE_FANOUT => 'AMQP_EX_TYPE_FANOUT',
         \AMQP_EX_TYPE_TOPIC => 'AMQP_EX_TYPE_TOPIC',
@@ -133,7 +133,7 @@ class AmqpCaster
             $prefix.'flags' => self::extractFlags($c->getFlags()),
         ];
 
-        $type = isset(self::$exchangeTypes[$c->getType()]) ? new ConstStub(self::$exchangeTypes[$c->getType()], $c->getType()) : $c->getType();
+        $type = isset(self::EXCHANGE_TYPES[$c->getType()]) ? new ConstStub(self::EXCHANGE_TYPES[$c->getType()], $c->getType()) : $c->getType();
 
         // Recent version of the extension already expose private properties
         if (isset($a["\x00AMQPExchange\x00name"])) {
@@ -197,7 +197,7 @@ class AmqpCaster
     {
         $flagsArray = [];
 
-        foreach (self::$flags as $value => $name) {
+        foreach (self::FLAGS as $value => $name) {
             if ($flags & $value) {
                 $flagsArray[] = $name;
             }
diff --git a/src/Symfony/Component/VarDumper/Caster/DOMCaster.php b/src/Symfony/Component/VarDumper/Caster/DOMCaster.php
index c6cfb75acd..5f2b9cd115 100644
--- a/src/Symfony/Component/VarDumper/Caster/DOMCaster.php
+++ b/src/Symfony/Component/VarDumper/Caster/DOMCaster.php
@@ -22,7 +22,7 @@ use Symfony\Component\VarDumper\Cloner\Stub;
  */
 class DOMCaster
 {
-    private static $errorCodes = [
+    private const ERROR_CODES = [
         \DOM_PHP_ERR => 'DOM_PHP_ERR',
         \DOM_INDEX_SIZE_ERR => 'DOM_INDEX_SIZE_ERR',
         \DOMSTRING_SIZE_ERR => 'DOMSTRING_SIZE_ERR',
@@ -42,7 +42,7 @@ class DOMCaster
         \DOM_VALIDATION_ERR => 'DOM_VALIDATION_ERR',
     ];
 
-    private static $nodeTypes = [
+    private const NODE_TYPES = [
         \XML_ELEMENT_NODE => 'XML_ELEMENT_NODE',
         \XML_ATTRIBUTE_NODE => 'XML_ATTRIBUTE_NODE',
         \XML_TEXT_NODE => 'XML_TEXT_NODE',
@@ -66,8 +66,8 @@ class DOMCaster
     public static function castException(\DOMException $e, array $a, Stub $stub, $isNested)
     {
         $k = Caster::PREFIX_PROTECTED.'code';
-        if (isset($a[$k], self::$errorCodes[$a[$k]])) {
-            $a[$k] = new ConstStub(self::$errorCodes[$a[$k]], $a[$k]);
+        if (isset($a[$k], self::ERROR_CODES[$a[$k]])) {
+            $a[$k] = new ConstStub(self::ERROR_CODES[$a[$k]], $a[$k]);
         }
 
         return $a;
@@ -97,7 +97,7 @@ class DOMCaster
         $a += [
             'nodeName' => $dom->nodeName,
             'nodeValue' => new CutStub($dom->nodeValue),
-            'nodeType' => new ConstStub(self::$nodeTypes[$dom->nodeType], $dom->nodeType),
+            'nodeType' => new ConstStub(self::NODE_TYPES[$dom->nodeType], $dom->nodeType),
             'parentNode' => new CutStub($dom->parentNode),
             'childNodes' => $dom->childNodes,
             'firstChild' => new CutStub($dom->firstChild),
@@ -121,7 +121,7 @@ class DOMCaster
         $a += [
             'nodeName' => $dom->nodeName,
             'nodeValue' => new CutStub($dom->nodeValue),
-            'nodeType' => new ConstStub(self::$nodeTypes[$dom->nodeType], $dom->nodeType),
+            'nodeType' => new ConstStub(self::NODE_TYPES[$dom->nodeType], $dom->nodeType),
             'prefix' => $dom->prefix,
             'localName' => $dom->localName,
             'namespaceURI' => $dom->namespaceURI,
diff --git a/src/Symfony/Component/VarDumper/Caster/PdoCaster.php b/src/Symfony/Component/VarDumper/Caster/PdoCaster.php
index d30ab01469..47b0a62b76 100644
--- a/src/Symfony/Component/VarDumper/Caster/PdoCaster.php
+++ b/src/Symfony/Component/VarDumper/Caster/PdoCaster.php
@@ -22,7 +22,7 @@ use Symfony\Component\VarDumper\Cloner\Stub;
  */
 class PdoCaster
 {
-    private static $pdoAttributes = [
+    private const PDO_ATTRIBUTES = [
         'CASE' => [
             \PDO::CASE_LOWER => 'LOWER',
             \PDO::CASE_NATURAL => 'NATURAL',
@@ -65,7 +65,7 @@ class PdoCaster
         $errmode = $c->getAttribute(\PDO::ATTR_ERRMODE);
         $c->setAttribute(\PDO::ATTR_ERRMODE, \PDO::ERRMODE_EXCEPTION);
 
-        foreach (self::$pdoAttributes as $k => $v) {
+        foreach (self::PDO_ATTRIBUTES as $k => $v) {
             if (!isset($k[0])) {
                 $k = $v;
                 $v = [];
diff --git a/src/Symfony/Component/VarDumper/Caster/PgSqlCaster.php b/src/Symfony/Component/VarDumper/Caster/PgSqlCaster.php
index 6098277c76..3097c5184c 100644
--- a/src/Symfony/Component/VarDumper/Caster/PgSqlCaster.php
+++ b/src/Symfony/Component/VarDumper/Caster/PgSqlCaster.php
@@ -22,7 +22,7 @@ use Symfony\Component\VarDumper\Cloner\Stub;
  */
 class PgSqlCaster
 {
-    private static $paramCodes = [
+    private const PARAM_CODES = [
         'server_encoding',
         'client_encoding',
         'is_superuser',
@@ -35,7 +35,7 @@ class PgSqlCaster
         'standard_conforming_strings',
     ];
 
-    private static $transactionStatus = [
+    private const TRANSACTION_STATUS = [
         \PGSQL_TRANSACTION_IDLE => 'PGSQL_TRANSACTION_IDLE',
         \PGSQL_TRANSACTION_ACTIVE => 'PGSQL_TRANSACTION_ACTIVE',
         \PGSQL_TRANSACTION_INTRANS => 'PGSQL_TRANSACTION_INTRANS',
@@ -43,7 +43,7 @@ class PgSqlCaster
         \PGSQL_TRANSACTION_UNKNOWN => 'PGSQL_TRANSACTION_UNKNOWN',
     ];
 
-    private static $resultStatus = [
+    private const RESULT_STATUS = [
         \PGSQL_EMPTY_QUERY => 'PGSQL_EMPTY_QUERY',
         \PGSQL_COMMAND_OK => 'PGSQL_COMMAND_OK',
         \PGSQL_TUPLES_OK => 'PGSQL_TUPLES_OK',
@@ -54,7 +54,7 @@ class PgSqlCaster
         \PGSQL_FATAL_ERROR => 'PGSQL_FATAL_ERROR',
     ];
 
-    private static $diagCodes = [
+    private const DIAG_CODES = [
         'severity' => \PGSQL_DIAG_SEVERITY,
         'sqlstate' => \PGSQL_DIAG_SQLSTATE,
         'message' => \PGSQL_DIAG_MESSAGE_PRIMARY,
@@ -83,8 +83,8 @@ class PgSqlCaster
         $a['busy'] = pg_connection_busy($link);
 
         $a['transaction'] = pg_transaction_status($link);
-        if (isset(self::$transactionStatus[$a['transaction']])) {
-            $a['transaction'] = new ConstStub(self::$transactionStatus[$a['transaction']], $a['transaction']);
+        if (isset(self::TRANSACTION_STATUS[$a['transaction']])) {
+            $a['transaction'] = new ConstStub(self::TRANSACTION_STATUS[$a['transaction']], $a['transaction']);
         }
 
         $a['pid'] = pg_get_pid($link);
@@ -96,7 +96,7 @@ class PgSqlCaster
         $a['options'] = pg_options($link);
         $a['version'] = pg_version($link);
 
-        foreach (self::$paramCodes as $v) {
+        foreach (self::PARAM_CODES as $v) {
             if (false !== $s = pg_parameter_status($link, $v)) {
                 $a['param'][$v] = $s;
             }
@@ -112,13 +112,13 @@ class PgSqlCaster
     {
         $a['num rows'] = pg_num_rows($result);
         $a['status'] = pg_result_status($result);
-        if (isset(self::$resultStatus[$a['status']])) {
-            $a['status'] = new ConstStub(self::$resultStatus[$a['status']], $a['status']);
+        if (isset(self::RESULT_STATUS[$a['status']])) {
+            $a['status'] = new ConstStub(self::RESULT_STATUS[$a['status']], $a['status']);
         }
         $a['command-completion tag'] = pg_result_status($result, \PGSQL_STATUS_STRING);
 
         if (-1 === $a['num rows']) {
-            foreach (self::$diagCodes as $k => $v) {
+            foreach (self::DIAG_CODES as $k => $v) {
                 $a['error'][$k] = pg_result_error_field($result, $v);
             }
         }
diff --git a/src/Symfony/Component/VarDumper/Caster/RedisCaster.php b/src/Symfony/Component/VarDumper/Caster/RedisCaster.php
index e92c65baeb..bd877cb3eb 100644
--- a/src/Symfony/Component/VarDumper/Caster/RedisCaster.php
+++ b/src/Symfony/Component/VarDumper/Caster/RedisCaster.php
@@ -22,24 +22,24 @@ use Symfony\Component\VarDumper\Cloner\Stub;
  */
 class RedisCaster
 {
-    private static $serializer = [
+    private const SERIALIZERS = [
         \Redis::SERIALIZER_NONE => 'NONE',
         \Redis::SERIALIZER_PHP => 'PHP',
         2 => 'IGBINARY', // Optional Redis::SERIALIZER_IGBINARY
     ];
 
-    private static $mode = [
+    private const MODES = [
         \Redis::ATOMIC => 'ATOMIC',
         \Redis::MULTI => 'MULTI',
         \Redis::PIPELINE => 'PIPELINE',
     ];
 
-    private static $compression = [
+    private const COMPRESSION_MODES = [
         0 => 'NONE', // Redis::COMPRESSION_NONE
         1 => 'LZF',  // Redis::COMPRESSION_LZF
     ];
 
-    private static $failover = [
+    private const FAILOVER_OPTIONS = [
         \RedisCluster::FAILOVER_NONE => 'NONE',
         \RedisCluster::FAILOVER_ERROR => 'ERROR',
         \RedisCluster::FAILOVER_DISTRIBUTE => 'DISTRIBUTE',
@@ -63,7 +63,7 @@ class RedisCaster
             $prefix.'host' => $c->getHost(),
             $prefix.'port' => $c->getPort(),
             $prefix.'auth' => $c->getAuth(),
-            $prefix.'mode' => isset(self::$mode[$mode]) ? new ConstStub(self::$mode[$mode], $mode) : $mode,
+            $prefix.'mode' => isset(self::MODES[$mode]) ? new ConstStub(self::MODES[$mode], $mode) : $mode,
             $prefix.'dbNum' => $c->getDbNum(),
             $prefix.'timeout' => $c->getTimeout(),
             $prefix.'lastError' => $c->getLastError(),
@@ -95,7 +95,7 @@ class RedisCaster
             $prefix.'mode' => new ConstStub($c->getMode() ? 'MULTI' : 'ATOMIC', $c->getMode()),
             $prefix.'lastError' => $c->getLastError(),
             $prefix.'options' => self::getRedisOptions($c, [
-                'SLAVE_FAILOVER' => isset(self::$failover[$failover]) ? new ConstStub(self::$failover[$failover], $failover) : $failover,
+                'SLAVE_FAILOVER' => isset(self::FAILOVER_OPTIONS[$failover]) ? new ConstStub(self::FAILOVER_OPTIONS[$failover], $failover) : $failover,
             ]),
         ];
 
@@ -110,23 +110,23 @@ class RedisCaster
         $serializer = $redis->getOption(\Redis::OPT_SERIALIZER);
         if (\is_array($serializer)) {
             foreach ($serializer as &$v) {
-                if (isset(self::$serializer[$v])) {
-                    $v = new ConstStub(self::$serializer[$v], $v);
+                if (isset(self::SERIALIZERS[$v])) {
+                    $v = new ConstStub(self::SERIALIZERS[$v], $v);
                 }
             }
-        } elseif (isset(self::$serializer[$serializer])) {
-            $serializer = new ConstStub(self::$serializer[$serializer], $serializer);
+        } elseif (isset(self::SERIALIZERS[$serializer])) {
+            $serializer = new ConstStub(self::SERIALIZERS[$serializer], $serializer);
         }
 
         $compression = \defined('Redis::OPT_COMPRESSION') ? $redis->getOption(\Redis::OPT_COMPRESSION) : 0;
         if (\is_array($compression)) {
             foreach ($compression as &$v) {
-                if (isset(self::$compression[$v])) {
-                    $v = new ConstStub(self::$compression[$v], $v);
+                if (isset(self::COMPRESSION_MODES[$v])) {
+                    $v = new ConstStub(self::COMPRESSION_MODES[$v], $v);
                 }
             }
-        } elseif (isset(self::$compression[$compression])) {
-            $compression = new ConstStub(self::$compression[$compression], $compression);
+        } elseif (isset(self::COMPRESSION_MODES[$compression])) {
+            $compression = new ConstStub(self::COMPRESSION_MODES[$compression], $compression);
         }
 
         $retry = \defined('Redis::OPT_SCAN') ? $redis->getOption(\Redis::OPT_SCAN) : 0;
diff --git a/src/Symfony/Component/VarDumper/Caster/ReflectionCaster.php b/src/Symfony/Component/VarDumper/Caster/ReflectionCaster.php
index 144269cadd..8d5f428e51 100644
--- a/src/Symfony/Component/VarDumper/Caster/ReflectionCaster.php
+++ b/src/Symfony/Component/VarDumper/Caster/ReflectionCaster.php
@@ -24,7 +24,7 @@ class ReflectionCaster
 {
     public const UNSET_CLOSURE_FILE_INFO = ['Closure' => __CLASS__.'::unsetClosureFileInfo'];
 
-    private static $extraMap = [
+    private const EXTRA_MAP = [
         'docComment' => 'getDocComment',
         'extension' => 'getExtensionName',
         'isDisabled' => 'isDisabled',
@@ -370,7 +370,7 @@ class ReflectionCaster
             $x['line'] = $c->getStartLine().' to '.$c->getEndLine();
         }
 
-        self::addMap($x, $c, self::$extraMap, '');
+        self::addMap($x, $c, self::EXTRA_MAP, '');
 
         if ($x) {
             $a[Caster::PREFIX_VIRTUAL.'extra'] = new EnumStub($x);
diff --git a/src/Symfony/Component/VarDumper/Caster/SplCaster.php b/src/Symfony/Component/VarDumper/Caster/SplCaster.php
index c8d55e1329..5abc51a9f3 100644
--- a/src/Symfony/Component/VarDumper/Caster/SplCaster.php
+++ b/src/Symfony/Component/VarDumper/Caster/SplCaster.php
@@ -22,7 +22,7 @@ use Symfony\Component\VarDumper\Cloner\Stub;
  */
 class SplCaster
 {
-    private static $splFileObjectFlags = [
+    private const SPL_FILE_OBJECT_FLAGS = [
         \SplFileObject::DROP_NEW_LINE => 'DROP_NEW_LINE',
         \SplFileObject::READ_AHEAD => 'READ_AHEAD',
         \SplFileObject::SKIP_EMPTY => 'SKIP_EMPTY',
@@ -169,7 +169,7 @@ class SplCaster
 
         if (isset($a[$prefix.'flags'])) {
             $flagsArray = [];
-            foreach (self::$splFileObjectFlags as $value => $name) {
+            foreach (self::SPL_FILE_OBJECT_FLAGS as $value => $name) {
                 if ($a[$prefix.'flags'] & $value) {
                     $flagsArray[] = $name;
                 }
diff --git a/src/Symfony/Component/VarDumper/Caster/SymfonyCaster.php b/src/Symfony/Component/VarDumper/Caster/SymfonyCaster.php
index ad7bb7166f..06f213ef0f 100644
--- a/src/Symfony/Component/VarDumper/Caster/SymfonyCaster.php
+++ b/src/Symfony/Component/VarDumper/Caster/SymfonyCaster.php
@@ -19,7 +19,7 @@ use Symfony\Component\VarDumper\Cloner\Stub;
  */
 class SymfonyCaster
 {
-    private static $requestGetters = [
+    private const REQUEST_GETTERS = [
         'pathInfo' => 'getPathInfo',
         'requestUri' => 'getRequestUri',
         'baseUrl' => 'getBaseUrl',
@@ -32,7 +32,7 @@ class SymfonyCaster
     {
         $clone = null;
 
-        foreach (self::$requestGetters as $prop => $getter) {
+        foreach (self::REQUEST_GETTERS as $prop => $getter) {
             $key = Caster::PREFIX_PROTECTED.$prop;
             if (\array_key_exists($key, $a) && null === $a[$key]) {
                 if (null === $clone) {
diff --git a/src/Symfony/Component/VarDumper/Caster/XmlReaderCaster.php b/src/Symfony/Component/VarDumper/Caster/XmlReaderCaster.php
index d18e47460c..19bf6a3d5e 100644
--- a/src/Symfony/Component/VarDumper/Caster/XmlReaderCaster.php
+++ b/src/Symfony/Component/VarDumper/Caster/XmlReaderCaster.php
@@ -21,7 +21,7 @@ use Symfony\Component\VarDumper\Cloner\Stub;
  */
 class XmlReaderCaster
 {
-    private static $nodeTypes = [
+    private const NODE_TYPES = [
         \XMLReader::NONE => 'NONE',
         \XMLReader::ELEMENT => 'ELEMENT',
         \XMLReader::ATTRIBUTE => 'ATTRIBUTE',
@@ -48,7 +48,7 @@ class XmlReaderCaster
         $info = [
             'localName' => $reader->localName,
             'prefix' => $reader->prefix,
-            'nodeType' => new ConstStub(self::$nodeTypes[$reader->nodeType], $reader->nodeType),
+            'nodeType' => new ConstStub(self::NODE_TYPES[$reader->nodeType], $reader->nodeType),
             'depth' => $reader->depth,
             'isDefault' => $reader->isDefault,
             'isEmptyElement' => \XMLReader::NONE === $reader->nodeType ? null : $reader->isEmptyElement,
diff --git a/src/Symfony/Component/VarDumper/Caster/XmlResourceCaster.php b/src/Symfony/Component/VarDumper/Caster/XmlResourceCaster.php
index 1d9d590d39..455fc065b8 100644
--- a/src/Symfony/Component/VarDumper/Caster/XmlResourceCaster.php
+++ b/src/Symfony/Component/VarDumper/Caster/XmlResourceCaster.php
@@ -22,7 +22,7 @@ use Symfony\Component\VarDumper\Cloner\Stub;
  */
 class XmlResourceCaster
 {
-    private static $xmlErrors = [
+    private const XML_ERRORS = [
         \XML_ERROR_NONE => 'XML_ERROR_NONE',
         \XML_ERROR_NO_MEMORY => 'XML_ERROR_NO_MEMORY',
         \XML_ERROR_SYNTAX => 'XML_ERROR_SYNTAX',
@@ -54,8 +54,8 @@ class XmlResourceCaster
         $a['current_line_number'] = xml_get_current_line_number($h);
         $a['error_code'] = xml_get_error_code($h);
 
-        if (isset(self::$xmlErrors[$a['error_code']])) {
-            $a['error_code'] = new ConstStub(self::$xmlErrors[$a['error_code']], $a['error_code']);
+        if (isset(self::XML_ERRORS[$a['error_code']])) {
+            $a['error_code'] = new ConstStub(self::XML_ERRORS[$a['error_code']], $a['error_code']);
         }
 
         return $a;
diff --git a/src/Symfony/Component/Yaml/Escaper.php b/src/Symfony/Component/Yaml/Escaper.php
index 78d93ddfe3..9b809df874 100644
--- a/src/Symfony/Component/Yaml/Escaper.php
+++ b/src/Symfony/Component/Yaml/Escaper.php
@@ -28,7 +28,7 @@ class Escaper
     // first to ensure proper escaping because str_replace operates iteratively
     // on the input arrays. This ordering of the characters avoids the use of strtr,
     // which performs more slowly.
-    private static $escapees = ['\\', '\\\\', '\\"', '"',
+    private const ESCAPEES = ['\\', '\\\\', '\\"', '"',
                                      "\x00",  "\x01",  "\x02",  "\x03",  "\x04",  "\x05",  "\x06",  "\x07",
                                      "\x08",  "\x09",  "\x0a",  "\x0b",  "\x0c",  "\x0d",  "\x0e",  "\x0f",
                                      "\x10",  "\x11",  "\x12",  "\x13",  "\x14",  "\x15",  "\x16",  "\x17",
@@ -36,7 +36,7 @@ class Escaper
                                      "\x7f",
                                      "\xc2\x85", "\xc2\xa0", "\xe2\x80\xa8", "\xe2\x80\xa9",
                                ];
-    private static $escaped = ['\\\\', '\\"', '\\\\', '\\"',
+    private const ESCAPED = ['\\\\', '\\"', '\\\\', '\\"',
                                      '\\0',   '\\x01', '\\x02', '\\x03', '\\x04', '\\x05', '\\x06', '\\a',
                                      '\\b',   '\\t',   '\\n',   '\\v',   '\\f',   '\\r',   '\\x0e', '\\x0f',
                                      '\\x10', '\\x11', '\\x12', '\\x13', '\\x14', '\\x15', '\\x16', '\\x17',
@@ -66,7 +66,7 @@ class Escaper
      */
     public static function escapeWithDoubleQuotes(string $value): string
     {
-        return sprintf('"%s"', str_replace(self::$escapees, self::$escaped, $value));
+        return sprintf('"%s"', str_replace(self::ESCAPEES, self::ESCAPED, $value));
     }
 
     /**