diff --git a/Attribute/DeprecatedAlias.php b/Attribute/DeprecatedAlias.php
new file mode 100644
index 00000000..ae5a6821
--- /dev/null
+++ b/Attribute/DeprecatedAlias.php
@@ -0,0 +1,46 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Routing\Attribute;
+
+/**
+ * This class is meant to be used in {@see Route} to define an alias for a route.
+ */
+class DeprecatedAlias
+{
+    public function __construct(
+        private string $aliasName,
+        private string $package,
+        private string $version,
+        private string $message = '',
+    ) {
+    }
+
+    public function getMessage(): string
+    {
+        return $this->message;
+    }
+
+    public function getAliasName(): string
+    {
+        return $this->aliasName;
+    }
+
+    public function getPackage(): string
+    {
+        return $this->package;
+    }
+
+    public function getVersion(): string
+    {
+        return $this->version;
+    }
+}
diff --git a/Attribute/Route.php b/Attribute/Route.php
index 07abc556..003bbe64 100644
--- a/Attribute/Route.php
+++ b/Attribute/Route.php
@@ -22,23 +22,28 @@ class Route
     private array $localizedPaths = [];
     private array $methods;
     private array $schemes;
+    /**
+     * @var (string|DeprecatedAlias)[]
+     */
+    private array $aliases = [];
 
     /**
-     * @param string|array<string,string>|null $path         The route path (i.e. "/user/login")
-     * @param string|null                      $name         The route name (i.e. "app_user_login")
-     * @param array<string|\Stringable>        $requirements Requirements for the route attributes, @see https://symfony.com/doc/current/routing.html#parameters-validation
-     * @param array<string, mixed>             $options      Options for the route (i.e. ['prefix' => '/api'])
-     * @param array<string, mixed>             $defaults     Default values for the route attributes and query parameters
-     * @param string|null                      $host         The host for which this route should be active (i.e. "localhost")
-     * @param string|string[]                  $methods      The list of HTTP methods allowed by this route
-     * @param string|string[]                  $schemes      The list of schemes allowed by this route (i.e. "https")
-     * @param string|null                      $condition    An expression that must evaluate to true for the route to be matched, @see https://symfony.com/doc/current/routing.html#matching-expressions
-     * @param int|null                         $priority     The priority of the route if multiple ones are defined for the same path
-     * @param string|null                      $locale       The locale accepted by the route
-     * @param string|null                      $format       The format returned by the route (i.e. "json", "xml")
-     * @param bool|null                        $utf8         Whether the route accepts UTF-8 in its parameters
-     * @param bool|null                        $stateless    Whether the route is defined as stateless or stateful, @see https://symfony.com/doc/current/routing.html#stateless-routes
-     * @param string|null                      $env          The env in which the route is defined (i.e. "dev", "test", "prod")
+     * @param string|array<string,string>|null                  $path         The route path (i.e. "/user/login")
+     * @param string|null                                       $name         The route name (i.e. "app_user_login")
+     * @param array<string|\Stringable>                         $requirements Requirements for the route attributes, @see https://symfony.com/doc/current/routing.html#parameters-validation
+     * @param array<string, mixed>                              $options      Options for the route (i.e. ['prefix' => '/api'])
+     * @param array<string, mixed>                              $defaults     Default values for the route attributes and query parameters
+     * @param string|null                                       $host         The host for which this route should be active (i.e. "localhost")
+     * @param string|string[]                                   $methods      The list of HTTP methods allowed by this route
+     * @param string|string[]                                   $schemes      The list of schemes allowed by this route (i.e. "https")
+     * @param string|null                                       $condition    An expression that must evaluate to true for the route to be matched, @see https://symfony.com/doc/current/routing.html#matching-expressions
+     * @param int|null                                          $priority     The priority of the route if multiple ones are defined for the same path
+     * @param string|null                                       $locale       The locale accepted by the route
+     * @param string|null                                       $format       The format returned by the route (i.e. "json", "xml")
+     * @param bool|null                                         $utf8         Whether the route accepts UTF-8 in its parameters
+     * @param bool|null                                         $stateless    Whether the route is defined as stateless or stateful, @see https://symfony.com/doc/current/routing.html#stateless-routes
+     * @param string|null                                       $env          The env in which the route is defined (i.e. "dev", "test", "prod")
+     * @param string|DeprecatedAlias|(string|DeprecatedAlias)[] $alias        The list of aliases for this route
      */
     public function __construct(
         string|array|null $path = null,
@@ -56,6 +61,7 @@ public function __construct(
         ?bool $utf8 = null,
         ?bool $stateless = null,
         private ?string $env = null,
+        string|DeprecatedAlias|array $alias = [],
     ) {
         if (\is_array($path)) {
             $this->localizedPaths = $path;
@@ -64,6 +70,7 @@ public function __construct(
         }
         $this->setMethods($methods);
         $this->setSchemes($schemes);
+        $this->setAliases($alias);
 
         if (null !== $locale) {
             $this->defaults['_locale'] = $locale;
@@ -201,6 +208,22 @@ public function getEnv(): ?string
     {
         return $this->env;
     }
+
+    /**
+     * @return (string|DeprecatedAlias)[]
+     */
+    public function getAliases(): array
+    {
+        return $this->aliases;
+    }
+
+    /**
+     * @param string|DeprecatedAlias|(string|DeprecatedAlias)[] $aliases
+     */
+    public function setAliases(string|DeprecatedAlias|array $aliases): void
+    {
+        $this->aliases = \is_array($aliases) ? $aliases : [$aliases];
+    }
 }
 
 if (!class_exists(\Symfony\Component\Routing\Annotation\Route::class, false)) {
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 7c461405..d21e550f 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,12 @@
 CHANGELOG
 =========
 
+7.3
+---
+
+ * Allow aliases and deprecations in `#[Route]` attribute
+ * Add the `Requirement::MONGODB_ID` constant to validate MongoDB ObjectIDs in hexadecimal format
+
 7.2
 ---
 
diff --git a/Loader/AttributeClassLoader.php b/Loader/AttributeClassLoader.php
index 92471af0..f2bc668d 100644
--- a/Loader/AttributeClassLoader.php
+++ b/Loader/AttributeClassLoader.php
@@ -13,8 +13,10 @@
 
 use Symfony\Component\Config\Loader\LoaderInterface;
 use Symfony\Component\Config\Loader\LoaderResolverInterface;
-use Symfony\Component\Config\Resource\FileResource;
+use Symfony\Component\Config\Resource\ReflectionClassResource;
+use Symfony\Component\Routing\Attribute\DeprecatedAlias;
 use Symfony\Component\Routing\Attribute\Route as RouteAttribute;
+use Symfony\Component\Routing\Exception\InvalidArgumentException;
 use Symfony\Component\Routing\Exception\LogicException;
 use Symfony\Component\Routing\Route;
 use Symfony\Component\Routing\RouteCollection;
@@ -102,11 +104,20 @@ public function load(mixed $class, ?string $type = null): RouteCollection
 
         $globals = $this->getGlobals($class);
         $collection = new RouteCollection();
-        $collection->addResource(new FileResource($class->getFileName()));
+        $collection->addResource(new ReflectionClassResource($class));
         if ($globals['env'] && $this->env !== $globals['env']) {
             return $collection;
         }
         $fqcnAlias = false;
+
+        if (!$class->hasMethod('__invoke')) {
+            foreach ($this->getAttributes($class) as $attr) {
+                if ($attr->getAliases()) {
+                    throw new InvalidArgumentException(\sprintf('Route aliases cannot be used on non-invokable class "%s".', $class->getName()));
+                }
+            }
+        }
+
         foreach ($class->getMethods() as $method) {
             $this->defaultRouteIndex = 0;
             $routeNamesBefore = array_keys($collection->all());
@@ -208,11 +219,11 @@ protected function addRoute(RouteCollection $collection, object $attr, array $gl
                 continue;
             }
             foreach ($paths as $locale => $path) {
-                if (preg_match(\sprintf('/\{%s(?:<.*?>)?\}/', preg_quote($param->name)), $path)) {
+                if (preg_match(\sprintf('/\{(?|([^\}:<]++):%s(?:\.[^\}<]++)?|(%1$s))(?:<.*?>)?\}/', preg_quote($param->name)), $path, $matches)) {
                     if (\is_scalar($defaultValue = $param->getDefaultValue()) || null === $defaultValue) {
-                        $defaults[$param->name] = $defaultValue;
+                        $defaults[$matches[1]] = $defaultValue;
                     } elseif ($defaultValue instanceof \BackedEnum) {
-                        $defaults[$param->name] = $defaultValue->value;
+                        $defaults[$matches[1]] = $defaultValue->value;
                     }
                     break;
                 }
@@ -230,6 +241,19 @@ protected function addRoute(RouteCollection $collection, object $attr, array $gl
             } else {
                 $collection->add($name, $route, $priority);
             }
+            foreach ($attr->getAliases() as $aliasAttribute) {
+                if ($aliasAttribute instanceof DeprecatedAlias) {
+                    $alias = $collection->addAlias($aliasAttribute->getAliasName(), $name);
+                    $alias->setDeprecated(
+                        $aliasAttribute->getPackage(),
+                        $aliasAttribute->getVersion(),
+                        $aliasAttribute->getMessage()
+                    );
+                    continue;
+                }
+
+                $collection->addAlias($aliasAttribute, $name);
+            }
         }
     }
 
diff --git a/Loader/AttributeDirectoryLoader.php b/Loader/AttributeDirectoryLoader.php
index 8bb59823..fff003dd 100644
--- a/Loader/AttributeDirectoryLoader.php
+++ b/Loader/AttributeDirectoryLoader.php
@@ -11,7 +11,7 @@
 
 namespace Symfony\Component\Routing\Loader;
 
-use Symfony\Component\Config\Resource\DirectoryResource;
+use Symfony\Component\Config\Resource\GlobResource;
 use Symfony\Component\Routing\RouteCollection;
 
 /**
@@ -33,7 +33,7 @@ public function load(mixed $path, ?string $type = null): ?RouteCollection
         }
 
         $collection = new RouteCollection();
-        $collection->addResource(new DirectoryResource($dir, '/\.php$/'));
+        $collection->addResource(new GlobResource($dir, '/*.php', true));
         $files = iterator_to_array(new \RecursiveIteratorIterator(
             new \RecursiveCallbackFilterIterator(
                 new \RecursiveDirectoryIterator($dir, \FilesystemIterator::SKIP_DOTS | \FilesystemIterator::FOLLOW_SYMLINKS),
diff --git a/Loader/AttributeFileLoader.php b/Loader/AttributeFileLoader.php
index 3214d589..ae0bad7a 100644
--- a/Loader/AttributeFileLoader.php
+++ b/Loader/AttributeFileLoader.php
@@ -13,7 +13,7 @@
 
 use Symfony\Component\Config\FileLocatorInterface;
 use Symfony\Component\Config\Loader\FileLoader;
-use Symfony\Component\Config\Resource\FileResource;
+use Symfony\Component\Config\Resource\ReflectionClassResource;
 use Symfony\Component\Routing\RouteCollection;
 
 /**
@@ -52,7 +52,7 @@ public function load(mixed $file, ?string $type = null): ?RouteCollection
                 return null;
             }
 
-            $collection->addResource(new FileResource($path));
+            $collection->addResource(new ReflectionClassResource($refl));
             $collection->addCollection($this->loader->load($class, $type));
         }
 
diff --git a/Loader/Configurator/CollectionConfigurator.php b/Loader/Configurator/CollectionConfigurator.php
index 4b83b0ff..d1553213 100644
--- a/Loader/Configurator/CollectionConfigurator.php
+++ b/Loader/Configurator/CollectionConfigurator.php
@@ -36,12 +36,12 @@ public function __construct(
         $this->route = new Route('');
     }
 
-    public function __sleep(): array
+    public function __serialize(): array
     {
         throw new \BadMethodCallException('Cannot serialize '.__CLASS__);
     }
 
-    public function __wakeup(): void
+    public function __unserialize(array $data): void
     {
         throw new \BadMethodCallException('Cannot unserialize '.__CLASS__);
     }
diff --git a/Loader/Configurator/ImportConfigurator.php b/Loader/Configurator/ImportConfigurator.php
index 45d1f6dc..b10bdf05 100644
--- a/Loader/Configurator/ImportConfigurator.php
+++ b/Loader/Configurator/ImportConfigurator.php
@@ -29,12 +29,12 @@ public function __construct(
         $this->route = $route;
     }
 
-    public function __sleep(): array
+    public function __serialize(): array
     {
         throw new \BadMethodCallException('Cannot serialize '.__CLASS__);
     }
 
-    public function __wakeup(): void
+    public function __unserialize(array $data): void
     {
         throw new \BadMethodCallException('Cannot unserialize '.__CLASS__);
     }
diff --git a/Loader/Configurator/Traits/PrefixTrait.php b/Loader/Configurator/Traits/PrefixTrait.php
index 9777c649..9f2284c5 100644
--- a/Loader/Configurator/Traits/PrefixTrait.php
+++ b/Loader/Configurator/Traits/PrefixTrait.php
@@ -27,10 +27,17 @@ final protected function addPrefix(RouteCollection $routes, string|array $prefix
             foreach ($prefix as $locale => $localePrefix) {
                 $prefix[$locale] = trim(trim($localePrefix), '/');
             }
+            $aliases = [];
+            foreach ($routes->getAliases() as $name => $alias) {
+                $aliases[$alias->getId()][] = $name;
+            }
             foreach ($routes->all() as $name => $route) {
                 if (null === $locale = $route->getDefault('_locale')) {
                     $priority = $routes->getPriority($name) ?? 0;
                     $routes->remove($name);
+                    foreach ($aliases[$name] ?? [] as $aliasName) {
+                        $routes->remove($aliasName);
+                    }
                     foreach ($prefix as $locale => $localePrefix) {
                         $localizedRoute = clone $route;
                         $localizedRoute->setDefault('_locale', $locale);
@@ -38,6 +45,9 @@ final protected function addPrefix(RouteCollection $routes, string|array $prefix
                         $localizedRoute->setDefault('_canonical_route', $name);
                         $localizedRoute->setPath($localePrefix.(!$trailingSlashOnRoot && '/' === $route->getPath() ? '' : $route->getPath()));
                         $routes->add($name.'.'.$locale, $localizedRoute, $priority);
+                        foreach ($aliases[$name] ?? [] as $aliasName) {
+                            $routes->addAlias($aliasName.'.'.$locale, $name.'.'.$locale);
+                        }
                     }
                 } elseif (!isset($prefix[$locale])) {
                     throw new \InvalidArgumentException(\sprintf('Route "%s" with locale "%s" is missing a corresponding prefix in its parent collection.', $name, $locale));
diff --git a/Loader/Psr4DirectoryLoader.php b/Loader/Psr4DirectoryLoader.php
index 738b56f4..fb48da15 100644
--- a/Loader/Psr4DirectoryLoader.php
+++ b/Loader/Psr4DirectoryLoader.php
@@ -15,6 +15,7 @@
 use Symfony\Component\Config\Loader\DirectoryAwareLoaderInterface;
 use Symfony\Component\Config\Loader\Loader;
 use Symfony\Component\Config\Resource\DirectoryResource;
+use Symfony\Component\Routing\Exception\InvalidArgumentException;
 use Symfony\Component\Routing\RouteCollection;
 
 /**
@@ -43,6 +44,10 @@ public function load(mixed $resource, ?string $type = null): ?RouteCollection
             return new RouteCollection();
         }
 
+        if (!preg_match('/^(?:[a-zA-Z_\x7f-\xff][a-zA-Z0-9_\x7f-\xff]*+\\\)++$/', trim($resource['namespace'], '\\').'\\')) {
+            throw new InvalidArgumentException(\sprintf('Namespace "%s" is not a valid PSR-4 prefix.', $resource['namespace']));
+        }
+
         return $this->loadFromDirectory($path, trim($resource['namespace'], '\\'));
     }
 
diff --git a/Matcher/Dumper/CompiledUrlMatcherDumper.php b/Matcher/Dumper/CompiledUrlMatcherDumper.php
index b719e755..d55b2d5f 100644
--- a/Matcher/Dumper/CompiledUrlMatcherDumper.php
+++ b/Matcher/Dumper/CompiledUrlMatcherDumper.php
@@ -219,7 +219,12 @@ private function compileStaticRoutes(array $staticRoutes, array &$conditions): a
         foreach ($staticRoutes as $url => $routes) {
             $compiledRoutes[$url] = [];
             foreach ($routes as $name => [$route, $hasTrailingSlash]) {
-                $compiledRoutes[$url][] = $this->compileRoute($route, $name, (!$route->compile()->getHostVariables() ? $route->getHost() : $route->compile()->getHostRegex()) ?: null, $hasTrailingSlash, false, $conditions);
+                if ($route->compile()->getHostVariables()) {
+                    $host = $route->compile()->getHostRegex();
+                } elseif ($host = $route->getHost()) {
+                    $host = strtolower($host);
+                }
+                $compiledRoutes[$url][] = $this->compileRoute($route, $name, $host ?: null, $hasTrailingSlash, false, $conditions);
             }
         }
 
diff --git a/Matcher/Dumper/CompiledUrlMatcherTrait.php b/Matcher/Dumper/CompiledUrlMatcherTrait.php
index db754e6d..5177c269 100644
--- a/Matcher/Dumper/CompiledUrlMatcherTrait.php
+++ b/Matcher/Dumper/CompiledUrlMatcherTrait.php
@@ -57,7 +57,7 @@ public function match(string $pathinfo): array
             } finally {
                 $this->context->setScheme($scheme);
             }
-        } elseif ('/' !== $trimmedPathinfo = rtrim($pathinfo, '/') ?: '/') {
+        } elseif ('' !== $trimmedPathinfo = rtrim($pathinfo, '/')) {
             $pathinfo = $trimmedPathinfo === $pathinfo ? $pathinfo.'/' : $trimmedPathinfo;
             if ($ret = $this->doMatch($pathinfo, $allow, $allowSchemes)) {
                 return $this->redirect($pathinfo, $ret['_route']) + $ret;
@@ -73,8 +73,8 @@ public function match(string $pathinfo): array
     private function doMatch(string $pathinfo, array &$allow = [], array &$allowSchemes = []): array
     {
         $allow = $allowSchemes = [];
-        $pathinfo = rawurldecode($pathinfo) ?: '/';
-        $trimmedPathinfo = rtrim($pathinfo, '/') ?: '/';
+        $pathinfo = '' === ($pathinfo = rawurldecode($pathinfo)) ? '/' : $pathinfo;
+        $trimmedPathinfo = '' === ($trimmedPathinfo = rtrim($pathinfo, '/')) ? '/' : $trimmedPathinfo;
         $context = $this->context;
         $requestMethod = $canonicalMethod = $context->getMethod();
 
diff --git a/Matcher/RedirectableUrlMatcher.php b/Matcher/RedirectableUrlMatcher.php
index 8d1ad4f9..3e7b78b5 100644
--- a/Matcher/RedirectableUrlMatcher.php
+++ b/Matcher/RedirectableUrlMatcher.php
@@ -41,7 +41,7 @@ public function match(string $pathinfo): array
                 } finally {
                     $this->context->setScheme($scheme);
                 }
-            } elseif ('/' === $trimmedPathinfo = rtrim($pathinfo, '/') ?: '/') {
+            } elseif ('' === $trimmedPathinfo = rtrim($pathinfo, '/')) {
                 throw $e;
             } else {
                 try {
diff --git a/Matcher/TraceableUrlMatcher.php b/Matcher/TraceableUrlMatcher.php
index 5dba38bc..5729df22 100644
--- a/Matcher/TraceableUrlMatcher.php
+++ b/Matcher/TraceableUrlMatcher.php
@@ -57,7 +57,7 @@ protected function matchCollection(string $pathinfo, RouteCollection $routes): a
             $method = 'GET';
         }
         $supportsTrailingSlash = 'GET' === $method && $this instanceof RedirectableUrlMatcherInterface;
-        $trimmedPathinfo = rtrim($pathinfo, '/') ?: '/';
+        $trimmedPathinfo = '' === ($trimmedPathinfo = rtrim($pathinfo, '/')) ? '/' : $trimmedPathinfo;
 
         foreach ($routes as $name => $route) {
             $compiledRoute = $route->compile();
diff --git a/Matcher/UrlMatcher.php b/Matcher/UrlMatcher.php
index 36698d50..76bd309b 100644
--- a/Matcher/UrlMatcher.php
+++ b/Matcher/UrlMatcher.php
@@ -70,8 +70,9 @@ public function getContext(): RequestContext
     public function match(string $pathinfo): array
     {
         $this->allow = $this->allowSchemes = [];
+        $pathinfo = '' === ($pathinfo = rawurldecode($pathinfo)) ? '/' : $pathinfo;
 
-        if ($ret = $this->matchCollection(rawurldecode($pathinfo) ?: '/', $this->routes)) {
+        if ($ret = $this->matchCollection($pathinfo, $this->routes)) {
             return $ret;
         }
 
@@ -114,7 +115,7 @@ protected function matchCollection(string $pathinfo, RouteCollection $routes): a
             $method = 'GET';
         }
         $supportsTrailingSlash = 'GET' === $method && $this instanceof RedirectableUrlMatcherInterface;
-        $trimmedPathinfo = rtrim($pathinfo, '/') ?: '/';
+        $trimmedPathinfo = '' === ($trimmedPathinfo = rtrim($pathinfo, '/')) ? '/' : $trimmedPathinfo;
 
         foreach ($routes as $name => $route) {
             $compiledRoute = $route->compile();
diff --git a/Requirement/Requirement.php b/Requirement/Requirement.php
index fdc0009c..6de2fbc5 100644
--- a/Requirement/Requirement.php
+++ b/Requirement/Requirement.php
@@ -20,6 +20,7 @@ enum Requirement
     public const CATCH_ALL = '.+';
     public const DATE_YMD = '[0-9]{4}-(?:0[1-9]|1[012])-(?:0[1-9]|[12][0-9]|(?<!02-)3[01])'; // YYYY-MM-DD
     public const DIGITS = '[0-9]+';
+    public const MONGODB_ID = '[0-9a-f]{24}';
     public const POSITIVE_INT = '[1-9][0-9]*';
     public const UID_BASE32 = '[0-9A-HJKMNP-TV-Z]{26}';
     public const UID_BASE58 = '[1-9A-HJ-NP-Za-km-z]{22}';
diff --git a/Route.php b/Route.php
index 0364fdd0..7bc46c8b 100644
--- a/Route.php
+++ b/Route.php
@@ -35,7 +35,7 @@ class Route implements \Serializable
      * Available options:
      *
      *  * compiler_class: A class name able to compile this route instance (RouteCompiler by default)
-     *  * utf8:           Whether UTF-8 matching is enforced ot not
+     *  * utf8:           Whether UTF-8 matching is enforced or not
      *
      * @param string                    $path         The path pattern to match
      * @param array                     $defaults     An array of default parameter values
@@ -418,15 +418,15 @@ private function extractInlineDefaultsAndRequirements(string $pattern): string
 
         $mapping = $this->getDefault('_route_mapping') ?? [];
 
-        $pattern = preg_replace_callback('#\{(!?)([\w\x80-\xFF]++)(:[\w\x80-\xFF]++)?(<.*?>)?(\?[^\}]*+)?\}#', function ($m) use (&$mapping) {
-            if (isset($m[5][0])) {
-                $this->setDefault($m[2], '?' !== $m[5] ? substr($m[5], 1) : null);
+        $pattern = preg_replace_callback('#\{(!?)([\w\x80-\xFF]++)(:([\w\x80-\xFF]++)(\.[\w\x80-\xFF]++)?)?(<.*?>)?(\?[^\}]*+)?\}#', function ($m) use (&$mapping) {
+            if (isset($m[7][0])) {
+                $this->setDefault($m[2], '?' !== $m[7] ? substr($m[7], 1) : null);
             }
-            if (isset($m[4][0])) {
-                $this->setRequirement($m[2], substr($m[4], 1, -1));
+            if (isset($m[6][0])) {
+                $this->setRequirement($m[2], substr($m[6], 1, -1));
             }
-            if (isset($m[3][0])) {
-                $mapping[$m[2]] = substr($m[3], 1);
+            if (isset($m[4][0])) {
+                $mapping[$m[2]] = isset($m[5][0]) ? [$m[4], substr($m[5], 1)] : $mapping[$m[2]] = [$m[4], $m[2]];
             }
 
             return '{'.$m[1].$m[2].'}';
diff --git a/RouteCollection.php b/RouteCollection.php
index 87e38985..7ca86cc3 100644
--- a/RouteCollection.php
+++ b/RouteCollection.php
@@ -228,7 +228,13 @@ public function addNamePrefix(string $prefix): void
         }
 
         foreach ($this->aliases as $name => $alias) {
-            $prefixedAliases[$prefix.$name] = $alias->withId($prefix.$alias->getId());
+            $targetId = $alias->getId();
+
+            if (isset($this->routes[$targetId]) || isset($this->aliases[$targetId])) {
+                $targetId = $prefix.$targetId;
+            }
+
+            $prefixedAliases[$prefix.$name] = $alias->withId($targetId);
         }
 
         $this->routes = $prefixedRoutes;
diff --git a/Tests/Attribute/RouteTest.php b/Tests/Attribute/RouteTest.php
index 2696991c..bbaa7563 100644
--- a/Tests/Attribute/RouteTest.php
+++ b/Tests/Attribute/RouteTest.php
@@ -9,7 +9,7 @@
  * file that was distributed with this source code.
  */
 
-namespace Symfony\Component\Routing\Tests\Annotation;
+namespace Symfony\Component\Routing\Tests\Attribute;
 
 use PHPUnit\Framework\TestCase;
 use Symfony\Component\Routing\Attribute\Route;
@@ -40,6 +40,7 @@ public static function getValidParameters(): iterable
             ['methods', 'getMethods', ['GET', 'POST']],
             ['host', 'getHost', '{locale}.example.com'],
             ['condition', 'getCondition', 'context.getMethod() == \'GET\''],
+            ['alias', 'getAliases', ['alias', 'completely_different_name']],
         ];
     }
 }
diff --git a/Tests/Fixtures/AttributeFixtures/AliasClassController.php b/Tests/Fixtures/AttributeFixtures/AliasClassController.php
new file mode 100644
index 00000000..c7e87128
--- /dev/null
+++ b/Tests/Fixtures/AttributeFixtures/AliasClassController.php
@@ -0,0 +1,29 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Routing\Tests\Fixtures\AttributeFixtures;
+
+use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+use Symfony\Component\Routing\Attribute\Route;
+
+#[Route('/hello', alias: ['alias', 'completely_different_name'])]
+class AliasClassController
+{
+    #[Route('/world')]
+    public function actionWorld()
+    {
+    }
+
+    #[Route('/symfony')]
+    public function actionSymfony()
+    {
+    }
+}
diff --git a/Tests/Fixtures/AttributeFixtures/AliasInvokableController.php b/Tests/Fixtures/AttributeFixtures/AliasInvokableController.php
new file mode 100644
index 00000000..dac27b67
--- /dev/null
+++ b/Tests/Fixtures/AttributeFixtures/AliasInvokableController.php
@@ -0,0 +1,23 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Routing\Tests\Fixtures\AttributeFixtures;
+
+use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;
+use Symfony\Component\Routing\Attribute\Route;
+
+#[Route('/path', name:'invokable_path', alias: ['alias', 'completely_different_name'])]
+class AliasInvokableController
+{
+    public function __invoke()
+    {
+    }
+}
diff --git a/Tests/Fixtures/AttributeFixtures/AliasRouteController.php b/Tests/Fixtures/AttributeFixtures/AliasRouteController.php
new file mode 100644
index 00000000..0b828576
--- /dev/null
+++ b/Tests/Fixtures/AttributeFixtures/AliasRouteController.php
@@ -0,0 +1,22 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Routing\Tests\Fixtures\AttributeFixtures;
+
+use Symfony\Component\Routing\Attribute\Route;
+
+class AliasRouteController
+{
+    #[Route('/path', name: 'action_with_alias', alias: ['alias', 'completely_different_name'])]
+    public function action()
+    {
+    }
+}
diff --git a/Tests/Fixtures/AttributeFixtures/DefaultValueController.php b/Tests/Fixtures/AttributeFixtures/DefaultValueController.php
index dc5d0c4e..5dcf5181 100644
--- a/Tests/Fixtures/AttributeFixtures/DefaultValueController.php
+++ b/Tests/Fixtures/AttributeFixtures/DefaultValueController.php
@@ -3,6 +3,7 @@
 namespace Symfony\Component\Routing\Tests\Fixtures\AttributeFixtures;
 
 use Symfony\Component\Routing\Attribute\Route;
+use Symfony\Component\Routing\Tests\Fixtures\AttributedClasses\BarClass;
 use Symfony\Component\Routing\Tests\Fixtures\Enum\TestIntBackedEnum;
 use Symfony\Component\Routing\Tests\Fixtures\Enum\TestStringBackedEnum;
 
@@ -30,4 +31,14 @@ public function stringEnumAction(TestStringBackedEnum $default = TestStringBacke
     public function intEnumAction(TestIntBackedEnum $default = TestIntBackedEnum::Diamonds)
     {
     }
+
+    #[Route(path: '/defaultMappedParam/{libelle:bar}', name: 'defaultMappedParam_default')]
+    public function defaultMappedParam(?BarClass $bar = null)
+    {
+    }
+
+    #[Route(path: '/defaultAdvancedMappedParam/{barLibelle:bar.libelle}', name: 'defaultAdvancedMappedParam_default')]
+    public function defaultAdvancedMappedParam(?BarClass $bar = null)
+    {
+    }
 }
diff --git a/Tests/Fixtures/AttributeFixtures/DeprecatedAliasCustomMessageRouteController.php b/Tests/Fixtures/AttributeFixtures/DeprecatedAliasCustomMessageRouteController.php
new file mode 100644
index 00000000..08b1afbd
--- /dev/null
+++ b/Tests/Fixtures/AttributeFixtures/DeprecatedAliasCustomMessageRouteController.php
@@ -0,0 +1,24 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Routing\Tests\Fixtures\AttributeFixtures;
+
+use Symfony\Component\Routing\Attribute\DeprecatedAlias;
+use Symfony\Component\Routing\Attribute\Route;
+
+class DeprecatedAliasCustomMessageRouteController
+{
+
+    #[Route('/path', name: 'action_with_deprecated_alias', alias: new DeprecatedAlias('my_other_alias_deprecated', 'MyBundleFixture', '1.0', message: '%alias_id% alias is deprecated.'))]
+    public function action()
+    {
+    }
+}
diff --git a/Tests/Fixtures/AttributeFixtures/DeprecatedAliasRouteController.php b/Tests/Fixtures/AttributeFixtures/DeprecatedAliasRouteController.php
new file mode 100644
index 00000000..06577cd7
--- /dev/null
+++ b/Tests/Fixtures/AttributeFixtures/DeprecatedAliasRouteController.php
@@ -0,0 +1,23 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Routing\Tests\Fixtures\AttributeFixtures;
+
+use Symfony\Component\Routing\Attribute\DeprecatedAlias;
+use Symfony\Component\Routing\Attribute\Route;
+
+class DeprecatedAliasRouteController
+{
+    #[Route('/path', name: 'action_with_deprecated_alias', alias: new DeprecatedAlias('my_other_alias_deprecated', 'MyBundleFixture', '1.0'))]
+    public function action()
+    {
+    }
+}
diff --git a/Tests/Fixtures/AttributeFixtures/FooController.php b/Tests/Fixtures/AttributeFixtures/FooController.php
index adbd038a..ba822865 100644
--- a/Tests/Fixtures/AttributeFixtures/FooController.php
+++ b/Tests/Fixtures/AttributeFixtures/FooController.php
@@ -55,4 +55,9 @@ public function host()
     public function condition()
     {
     }
+
+    #[Route(alias: ['alias', 'completely_different_name'])]
+    public function alias()
+    {
+    }
 }
diff --git a/Tests/Fixtures/AttributeFixtures/MultipleDeprecatedAliasRouteController.php b/Tests/Fixtures/AttributeFixtures/MultipleDeprecatedAliasRouteController.php
new file mode 100644
index 00000000..93662d38
--- /dev/null
+++ b/Tests/Fixtures/AttributeFixtures/MultipleDeprecatedAliasRouteController.php
@@ -0,0 +1,27 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Routing\Tests\Fixtures\AttributeFixtures;
+
+use Symfony\Component\Routing\Attribute\DeprecatedAlias;
+use Symfony\Component\Routing\Attribute\Route;
+
+class MultipleDeprecatedAliasRouteController
+{
+    #[Route('/path', name: 'action_with_multiple_deprecated_alias', alias: [
+        new DeprecatedAlias('my_first_alias_deprecated', 'MyFirstBundleFixture', '1.0'),
+        new DeprecatedAlias('my_second_alias_deprecated', 'MySecondBundleFixture', '2.0'),
+        new DeprecatedAlias('my_third_alias_deprecated', 'SurprisedThirdBundleFixture', '3.0'),
+    ])]
+    public function action()
+    {
+    }
+}
diff --git a/Tests/Loader/AttributeClassLoaderTest.php b/Tests/Loader/AttributeClassLoaderTest.php
index afad8731..022e0c9f 100644
--- a/Tests/Loader/AttributeClassLoaderTest.php
+++ b/Tests/Loader/AttributeClassLoaderTest.php
@@ -16,8 +16,13 @@
 use Symfony\Component\Routing\Exception\LogicException;
 use Symfony\Component\Routing\Tests\Fixtures\AttributeFixtures\AbstractClassController;
 use Symfony\Component\Routing\Tests\Fixtures\AttributeFixtures\ActionPathController;
+use Symfony\Component\Routing\Tests\Fixtures\AttributeFixtures\AliasClassController;
+use Symfony\Component\Routing\Tests\Fixtures\AttributeFixtures\AliasInvokableController;
+use Symfony\Component\Routing\Tests\Fixtures\AttributeFixtures\AliasRouteController;
 use Symfony\Component\Routing\Tests\Fixtures\AttributeFixtures\BazClass;
 use Symfony\Component\Routing\Tests\Fixtures\AttributeFixtures\DefaultValueController;
+use Symfony\Component\Routing\Tests\Fixtures\AttributeFixtures\DeprecatedAliasCustomMessageRouteController;
+use Symfony\Component\Routing\Tests\Fixtures\AttributeFixtures\DeprecatedAliasRouteController;
 use Symfony\Component\Routing\Tests\Fixtures\AttributeFixtures\EncodingClass;
 use Symfony\Component\Routing\Tests\Fixtures\AttributeFixtures\ExplicitLocalizedActionPathController;
 use Symfony\Component\Routing\Tests\Fixtures\AttributeFixtures\ExtendedRouteOnClassController;
@@ -35,6 +40,7 @@
 use Symfony\Component\Routing\Tests\Fixtures\AttributeFixtures\MethodActionControllers;
 use Symfony\Component\Routing\Tests\Fixtures\AttributeFixtures\MethodsAndSchemes;
 use Symfony\Component\Routing\Tests\Fixtures\AttributeFixtures\MissingRouteNameController;
+use Symfony\Component\Routing\Tests\Fixtures\AttributeFixtures\MultipleDeprecatedAliasRouteController;
 use Symfony\Component\Routing\Tests\Fixtures\AttributeFixtures\NothingButNameController;
 use Symfony\Component\Routing\Tests\Fixtures\AttributeFixtures\PrefixedActionLocalizedRouteController;
 use Symfony\Component\Routing\Tests\Fixtures\AttributeFixtures\PrefixedActionPathController;
@@ -165,12 +171,16 @@ public function testLocalizedPathRoutesWithExplicitPathPropety()
     public function testDefaultValuesForMethods()
     {
         $routes = $this->loader->load(DefaultValueController::class);
-        $this->assertCount(5, $routes);
+        $this->assertCount(7, $routes);
         $this->assertEquals('/{default}/path', $routes->get('action')->getPath());
         $this->assertEquals('value', $routes->get('action')->getDefault('default'));
         $this->assertEquals('Symfony', $routes->get('hello_with_default')->getDefault('name'));
         $this->assertEquals('World', $routes->get('hello_without_default')->getDefault('name'));
         $this->assertEquals('diamonds', $routes->get('string_enum_action')->getDefault('default'));
+        $this->assertArrayHasKey('libelle', $routes->get('defaultMappedParam_default')->getDefaults());
+        $this->assertNull($routes->get('defaultMappedParam_default')->getDefault('libelle'));
+        $this->assertArrayHasKey('barLibelle', $routes->get('defaultAdvancedMappedParam_default')->getDefaults());
+        $this->assertNull($routes->get('defaultAdvancedMappedParam_default')->getDefault('barLibelle'));
         $this->assertEquals(20, $routes->get('int_enum_action')->getDefault('default'));
     }
 
@@ -364,4 +374,98 @@ public function testDefaultRouteName()
 
         $this->assertSame('symfony_component_routing_tests_fixtures_attributefixtures_encodingclass_routeàction', $defaultName);
     }
+
+    public function testAliasesOnMethod()
+    {
+        $routes = $this->loader->load(AliasRouteController::class);
+        $route = $routes->get('action_with_alias');
+        $this->assertCount(1, $routes);
+        $this->assertSame('/path', $route->getPath());
+        $this->assertEquals(new Alias('action_with_alias'), $routes->getAlias('alias'));
+        $this->assertEquals(new Alias('action_with_alias'), $routes->getAlias('completely_different_name'));
+    }
+
+    public function testThrowsWithAliasesOnClass()
+    {
+        $this->expectException(\InvalidArgumentException::class);
+        $this->expectExceptionMessage('Route aliases cannot be used on non-invokable class "Symfony\Component\Routing\Tests\Fixtures\AttributeFixtures\AliasClassController".');
+
+        $this->loader->load(AliasClassController::class);
+    }
+
+    public function testAliasesOnInvokableClass()
+    {
+        $routes = $this->loader->load(AliasInvokableController::class);
+        $route = $routes->get('invokable_path');
+        $this->assertCount(1, $routes);
+        $this->assertSame('/path', $route->getPath());
+        $this->assertEquals(new Alias('invokable_path'), $routes->getAlias('alias'));
+        $this->assertEquals(new Alias('invokable_path'), $routes->getAlias('completely_different_name'));
+    }
+
+    public function testDeprecatedAlias()
+    {
+        $routes = $this->loader->load(DeprecatedAliasRouteController::class);
+        $route = $routes->get('action_with_deprecated_alias');
+        $expected = (new Alias('action_with_deprecated_alias'))
+            ->setDeprecated(
+                'MyBundleFixture',
+                '1.0',
+                'The "%alias_id%" route alias is deprecated. You should stop using it, as it will be removed in the future.'
+            );
+        $actual = $routes->getAlias('my_other_alias_deprecated');
+        $this->assertCount(1, $routes);
+        $this->assertSame('/path', $route->getPath());
+        $this->assertEquals($expected, $actual);
+    }
+
+    public function testDeprecatedAliasWithCustomMessage()
+    {
+        $routes = $this->loader->load(DeprecatedAliasCustomMessageRouteController::class);
+        $route = $routes->get('action_with_deprecated_alias');
+        $expected = (new Alias('action_with_deprecated_alias'))
+            ->setDeprecated(
+                'MyBundleFixture',
+                '1.0',
+                '%alias_id% alias is deprecated.'
+            );
+        $actual = $routes->getAlias('my_other_alias_deprecated');
+        $this->assertCount(1, $routes);
+        $this->assertSame('/path', $route->getPath());
+        $this->assertEquals($expected, $actual);
+    }
+
+    public function testMultipleDeprecatedAlias()
+    {
+        $routes = $this->loader->load(MultipleDeprecatedAliasRouteController::class);
+        $route = $routes->get('action_with_multiple_deprecated_alias');
+        $this->assertCount(1, $routes);
+        $this->assertSame('/path', $route->getPath());
+
+        $dataset = [
+            'my_first_alias_deprecated' => [
+                'package' => 'MyFirstBundleFixture',
+                'version' => '1.0',
+            ],
+            'my_second_alias_deprecated' => [
+                'package' => 'MySecondBundleFixture',
+                'version' => '2.0',
+            ],
+            'my_third_alias_deprecated' => [
+                'package' => 'SurprisedThirdBundleFixture',
+                'version' => '3.0',
+            ],
+        ];
+
+        foreach ($dataset as $aliasName => $aliasData) {
+            $expected = (new Alias('action_with_multiple_deprecated_alias'))
+                ->setDeprecated(
+                    $aliasData['package'],
+                    $aliasData['version'],
+                    'The "%alias_id%" route alias is deprecated. You should stop using it, as it will be removed in the future.'
+                );
+            $actual = $routes->getAlias($aliasName);
+            $this->assertEquals($expected, $actual);
+        }
+    }
 }
diff --git a/Tests/Loader/Configurator/Traits/PrefixTraitTest.php b/Tests/Loader/Configurator/Traits/PrefixTraitTest.php
new file mode 100644
index 00000000..aa63af31
--- /dev/null
+++ b/Tests/Loader/Configurator/Traits/PrefixTraitTest.php
@@ -0,0 +1,53 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Routing\Tests\Loader\Configurator\Traits;
+
+use PHPUnit\Framework\TestCase;
+use Symfony\Component\Routing\Loader\Configurator\Traits\PrefixTrait;
+use Symfony\Component\Routing\Route;
+use Symfony\Component\Routing\RouteCollection;
+
+class PrefixTraitTest extends TestCase
+{
+    public function testAddLocalizedPrefixUpdatesAliases()
+    {
+        $collection = new RouteCollection();
+        $collection->add('app_route', new Route('/path'));
+        $collection->addAlias('app_alias', 'app_route');
+
+        $trait = new class {
+            use PrefixTrait;
+
+            public function add(RouteCollection $c, array $p)
+            {
+                $this->addPrefix($c, $p, false);
+            }
+        };
+
+        $trait->add($collection, ['en' => '/en', 'fr' => '/fr']);
+
+        $this->assertNull($collection->get('app_route'));
+
+        $this->assertNotNull($collection->get('app_route.en'));
+        $this->assertNotNull($collection->get('app_route.fr'));
+
+        $this->assertNull($collection->getAlias('app_alias'), 'The original alias should be removed as its target no longer exists');
+
+        $aliasEn = $collection->getAlias('app_alias.en');
+        $this->assertNotNull($aliasEn, 'Localized alias for EN should exist');
+        $this->assertEquals('app_route.en', $aliasEn->getId());
+
+        $aliasFr = $collection->getAlias('app_alias.fr');
+        $this->assertNotNull($aliasFr, 'Localized alias for FR should exist');
+        $this->assertEquals('app_route.fr', $aliasFr->getId());
+    }
+}
diff --git a/Tests/Loader/Psr4DirectoryLoaderTest.php b/Tests/Loader/Psr4DirectoryLoaderTest.php
index 81515b86..0720caca 100644
--- a/Tests/Loader/Psr4DirectoryLoaderTest.php
+++ b/Tests/Loader/Psr4DirectoryLoaderTest.php
@@ -15,6 +15,7 @@
 use Symfony\Component\Config\FileLocator;
 use Symfony\Component\Config\Loader\DelegatingLoader;
 use Symfony\Component\Config\Loader\LoaderResolver;
+use Symfony\Component\Routing\Exception\InvalidArgumentException;
 use Symfony\Component\Routing\Loader\AttributeClassLoader;
 use Symfony\Component\Routing\Loader\Psr4DirectoryLoader;
 use Symfony\Component\Routing\Route;
@@ -90,6 +91,34 @@ public static function provideNamespacesThatNeedTrimming(): array
         ];
     }
 
+    /**
+     * @dataProvider provideInvalidPsr4Namespaces
+     */
+    public function testInvalidPsr4Namespace(string $namespace, string $expectedExceptionMessage)
+    {
+        $this->expectException(InvalidArgumentException::class);
+        $this->expectExceptionMessage($expectedExceptionMessage);
+
+        $this->getLoader()->load(
+            ['path' => 'Psr4Controllers', 'namespace' => $namespace],
+            'attribute'
+        );
+    }
+
+    public static function provideInvalidPsr4Namespaces(): array
+    {
+        return [
+            'slash instead of back-slash' => [
+                'namespace' => 'App\Application/Controllers',
+                'expectedExceptionMessage' => 'Namespace "App\Application/Controllers" is not a valid PSR-4 prefix.',
+            ],
+            'invalid namespace' => [
+                'namespace' => 'App\Contro llers',
+                'expectedExceptionMessage' => 'Namespace "App\Contro llers" is not a valid PSR-4 prefix.',
+            ],
+        ];
+    }
+
     private function loadPsr4Controllers(): RouteCollection
     {
         return $this->getLoader()->load(
diff --git a/Tests/Matcher/CompiledUrlMatcherTest.php b/Tests/Matcher/CompiledUrlMatcherTest.php
index fd8e694e..fa812813 100644
--- a/Tests/Matcher/CompiledUrlMatcherTest.php
+++ b/Tests/Matcher/CompiledUrlMatcherTest.php
@@ -13,11 +13,33 @@
 
 use Symfony\Component\Routing\Matcher\CompiledUrlMatcher;
 use Symfony\Component\Routing\Matcher\Dumper\CompiledUrlMatcherDumper;
+use Symfony\Component\Routing\Matcher\UrlMatcher;
 use Symfony\Component\Routing\RequestContext;
+use Symfony\Component\Routing\Route;
 use Symfony\Component\Routing\RouteCollection;
 
 class CompiledUrlMatcherTest extends UrlMatcherTest
 {
+    public function testStaticHostIsCaseInsensitive()
+    {
+        $collection = new RouteCollection();
+        $collection->add('static_host_route', new Route('/test', [], [], [], 'API.example.com'));
+
+        $context = new RequestContext('/test', 'GET', 'api.example.com');
+        $matcher = new UrlMatcher($collection, $context);
+
+        $result = $matcher->match('/test');
+        $this->assertEquals('static_host_route', $result['_route'], 'UrlMatcher should match case-insensitive host');
+
+        $dumper = new CompiledUrlMatcherDumper($collection);
+        $compiledRoutes = $dumper->getCompiledRoutes();
+
+        $compiledMatcher = new CompiledUrlMatcher($compiledRoutes, $context);
+
+        $result = $compiledMatcher->match('/test');
+        $this->assertEquals('static_host_route', $result['_route'], 'CompiledUrlMatcher should match case-insensitive host');
+    }
+
     protected function getUrlMatcher(RouteCollection $routes, ?RequestContext $context = null)
     {
         $dumper = new CompiledUrlMatcherDumper($routes);
diff --git a/Tests/Matcher/UrlMatcherTest.php b/Tests/Matcher/UrlMatcherTest.php
index d8b14c31..eb5dd47a 100644
--- a/Tests/Matcher/UrlMatcherTest.php
+++ b/Tests/Matcher/UrlMatcherTest.php
@@ -22,6 +22,17 @@
 
 class UrlMatcherTest extends TestCase
 {
+    public function testZero()
+    {
+        $coll = new RouteCollection();
+        $coll->add('index', new Route('/'));
+
+        $matcher = $this->getUrlMatcher($coll);
+
+        $this->expectException(ResourceNotFoundException::class);
+        $matcher->match('0');
+    }
+
     public function testNoMethodSoAllowed()
     {
         $coll = new RouteCollection();
@@ -1035,7 +1046,30 @@ public function testMapping()
             '_route' => 'a',
             'slug' => 'vienna-2024',
             '_route_mapping' => [
-                'slug' => 'conference',
+                'slug' => [
+                    'conference',
+                    'slug',
+                ],
+            ],
+        ];
+        $this->assertEquals($expected, $matcher->match('/conference/vienna-2024'));
+    }
+
+    public function testMappingwithAlias()
+    {
+        $collection = new RouteCollection();
+        $collection->add('a', new Route('/conference/{conferenceSlug:conference.slug}'));
+
+        $matcher = $this->getUrlMatcher($collection);
+
+        $expected = [
+            '_route' => 'a',
+            'conferenceSlug' => 'vienna-2024',
+            '_route_mapping' => [
+                'conferenceSlug' => [
+                    'conference',
+                    'slug',
+                ],
             ],
         ];
         $this->assertEquals($expected, $matcher->match('/conference/vienna-2024'));
diff --git a/Tests/Requirement/RequirementTest.php b/Tests/Requirement/RequirementTest.php
index 814deadd..d7e0ba07 100644
--- a/Tests/Requirement/RequirementTest.php
+++ b/Tests/Requirement/RequirementTest.php
@@ -137,6 +137,32 @@ public function testDigitsKO(string $digits)
         );
     }
 
+    /**
+     * @testWith    ["67c8b7d295c70befc3070bf2"]
+     *              ["000000000000000000000000"]
+     */
+    public function testMongoDbIdOK(string $id)
+    {
+        $this->assertMatchesRegularExpression(
+            (new Route('/{id}', [], ['id' => Requirement::MONGODB_ID]))->compile()->getRegex(),
+            '/'.$id,
+        );
+    }
+
+    /**
+     * @testWith    ["67C8b7D295C70BEFC3070BF2"]
+     *              ["67c8b7d295c70befc3070bg2"]
+     *              ["67c8b7d295c70befc3070bf2a"]
+     *              ["67c8b7d295c70befc3070bf"]
+     */
+    public function testMongoDbIdKO(string $id)
+    {
+        $this->assertDoesNotMatchRegularExpression(
+            (new Route('/{id}', [], ['id' => Requirement::MONGODB_ID]))->compile()->getRegex(),
+            '/'.$id,
+        );
+    }
+
     /**
      * @testWith    ["1"]
      *              ["42"]
diff --git a/Tests/RouteCollectionTest.php b/Tests/RouteCollectionTest.php
index 7625bcf5..16ab7f6f 100644
--- a/Tests/RouteCollectionTest.php
+++ b/Tests/RouteCollectionTest.php
@@ -385,4 +385,18 @@ public function testAddWithPriorityAndPrefix()
 
         $this->assertSame($expected, $collection3->all());
     }
+
+    public function testAddNamePrefixDoesNotBreakExternalAliases()
+    {
+        $collection = new RouteCollection();
+        $collection->add('local_route', new Route('/local'));
+        $collection->addAlias('alias_to_local', 'local_route');
+        $collection->addAlias('alias_to_external', 'external_route');
+        $collection->addNamePrefix('prefix_');
+
+        $aliases = $collection->getAliases();
+
+        $this->assertEquals('prefix_local_route', $aliases['prefix_alias_to_local']->getId(), 'Alias to local route should have its target prefixed');
+        $this->assertEquals('external_route', $aliases['prefix_alias_to_external']->getId(), 'Alias to external route should NOT have its target prefixed');
+    }
 }
diff --git a/Tests/RouteTest.php b/Tests/RouteTest.php
index b58358a3..34728042 100644
--- a/Tests/RouteTest.php
+++ b/Tests/RouteTest.php
@@ -226,37 +226,48 @@ public function testSerialize()
         $this->assertNotSame($route, $unserialized);
     }
 
-    public function testInlineDefaultAndRequirement()
+    /**
+     * @dataProvider provideInlineDefaultAndRequirementCases
+     */
+    public function testInlineDefaultAndRequirement(Route $route, string $expectedPath, string $expectedHost, array $expectedDefaults, array $expectedRequirements)
+    {
+        self::assertSame($expectedPath, $route->getPath());
+        self::assertSame($expectedHost, $route->getHost());
+        self::assertSame($expectedDefaults, $route->getDefaults());
+        self::assertSame($expectedRequirements, $route->getRequirements());
+    }
+
+    public static function provideInlineDefaultAndRequirementCases(): iterable
     {
-        $this->assertEquals((new Route('/foo/{bar}'))->setDefault('bar', null), new Route('/foo/{bar?}'));
-        $this->assertEquals((new Route('/foo/{bar}'))->setDefault('bar', 'baz'), new Route('/foo/{bar?baz}'));
-        $this->assertEquals((new Route('/foo/{bar}'))->setDefault('bar', 'baz<buz>'), new Route('/foo/{bar?baz<buz>}'));
-        $this->assertEquals((new Route('/foo/{!bar}'))->setDefault('bar', 'baz<buz>'), new Route('/foo/{!bar?baz<buz>}'));
-        $this->assertEquals((new Route('/foo/{bar}'))->setDefault('bar', 'baz'), new Route('/foo/{bar?}', ['bar' => 'baz']));
-
-        $this->assertEquals((new Route('/foo/{bar}'))->setRequirement('bar', '.*'), new Route('/foo/{bar<.*>}'));
-        $this->assertEquals((new Route('/foo/{bar}'))->setRequirement('bar', '>'), new Route('/foo/{bar<>>}'));
-        $this->assertEquals((new Route('/foo/{bar}'))->setRequirement('bar', '\d+'), new Route('/foo/{bar<.*>}', [], ['bar' => '\d+']));
-        $this->assertEquals((new Route('/foo/{bar}'))->setRequirement('bar', '[a-z]{2}'), new Route('/foo/{bar<[a-z]{2}>}'));
-        $this->assertEquals((new Route('/foo/{!bar}'))->setRequirement('bar', '\d+'), new Route('/foo/{!bar<\d+>}'));
-
-        $this->assertEquals((new Route('/foo/{bar}'))->setDefault('bar', null)->setRequirement('bar', '.*'), new Route('/foo/{bar<.*>?}'));
-        $this->assertEquals((new Route('/foo/{bar}'))->setDefault('bar', '<>')->setRequirement('bar', '>'), new Route('/foo/{bar<>>?<>}'));
-
-        $this->assertEquals((new Route('/{foo}/{!bar}'))->setDefaults(['bar' => '<>', 'foo' => '\\'])->setRequirements(['bar' => '\\', 'foo' => '.']), new Route('/{foo<.>?\}/{!bar<\>?<>}'));
-
-        $this->assertEquals((new Route('/'))->setHost('{bar}')->setDefault('bar', null), (new Route('/'))->setHost('{bar?}'));
-        $this->assertEquals((new Route('/'))->setHost('{bar}')->setDefault('bar', 'baz'), (new Route('/'))->setHost('{bar?baz}'));
-        $this->assertEquals((new Route('/'))->setHost('{bar}')->setDefault('bar', 'baz<buz>'), (new Route('/'))->setHost('{bar?baz<buz>}'));
-        $this->assertEquals((new Route('/'))->setHost('{bar}')->setDefault('bar', null), (new Route('/', ['bar' => 'baz']))->setHost('{bar?}'));
-
-        $this->assertEquals((new Route('/'))->setHost('{bar}')->setRequirement('bar', '.*'), (new Route('/'))->setHost('{bar<.*>}'));
-        $this->assertEquals((new Route('/'))->setHost('{bar}')->setRequirement('bar', '>'), (new Route('/'))->setHost('{bar<>>}'));
-        $this->assertEquals((new Route('/'))->setHost('{bar}')->setRequirement('bar', '.*'), (new Route('/', [], ['bar' => '\d+']))->setHost('{bar<.*>}'));
-        $this->assertEquals((new Route('/'))->setHost('{bar}')->setRequirement('bar', '[a-z]{2}'), (new Route('/'))->setHost('{bar<[a-z]{2}>}'));
-
-        $this->assertEquals((new Route('/'))->setHost('{bar}')->setDefault('bar', null)->setRequirement('bar', '.*'), (new Route('/'))->setHost('{bar<.*>?}'));
-        $this->assertEquals((new Route('/'))->setHost('{bar}')->setDefault('bar', '<>')->setRequirement('bar', '>'), (new Route('/'))->setHost('{bar<>>?<>}'));
+        yield [new Route('/foo/{bar?}'), '/foo/{bar}', '', ['bar' => null], []];
+        yield [new Route('/foo/{bar?baz}'), '/foo/{bar}', '', ['bar' => 'baz'], []];
+        yield [new Route('/foo/{bar?baz<buz>}'), '/foo/{bar}', '', ['bar' => 'baz<buz>'], []];
+        yield [new Route('/foo/{!bar?baz<buz>}'), '/foo/{!bar}', '', ['bar' => 'baz<buz>'], []];
+        yield [new Route('/foo/{bar?}', ['bar' => 'baz']), '/foo/{bar}', '', ['bar' => 'baz'], []];
+
+        yield [new Route('/foo/{bar<.*>}'), '/foo/{bar}', '', [], ['bar' => '.*']];
+        yield [new Route('/foo/{bar<>>}'), '/foo/{bar}', '', [], ['bar' => '>']];
+        yield [new Route('/foo/{bar<.*>}', [], ['bar' => '\d+']), '/foo/{bar}', '', [], ['bar' => '\d+']];
+        yield [new Route('/foo/{bar<[a-z]{2}>}'), '/foo/{bar}', '', [], ['bar' => '[a-z]{2}']];
+        yield [new Route('/foo/{!bar<\d+>}'), '/foo/{!bar}', '', [], ['bar' => '\d+']];
+
+        yield [new Route('/foo/{bar<.*>?}'), '/foo/{bar}', '', ['bar' => null], ['bar' => '.*']];
+        yield [new Route('/foo/{bar<>>?<>}'), '/foo/{bar}', '', ['bar' => '<>'], ['bar' => '>']];
+
+        yield [new Route('/{foo<.>?\}/{!bar<\>?<>}'), '/{foo}/{!bar}', '', ['foo' => '\\', 'bar' => '<>'], ['foo' => '.', 'bar' => '\\']];
+
+        yield [new Route('/', host: '{bar?}'), '/', '{bar}', ['bar' => null], []];
+        yield [new Route('/', host: '{bar?baz}'), '/', '{bar}', ['bar' => 'baz'], []];
+        yield [new Route('/', host: '{bar?baz<buz>}'), '/', '{bar}', ['bar' => 'baz<buz>'], []];
+        yield [new Route('/', ['bar' => 'baz'], host: '{bar?}'), '/', '{bar}', ['bar' => null], []];
+
+        yield [new Route('/', host: '{bar<.*>}'), '/', '{bar}', [], ['bar' => '.*']];
+        yield [new Route('/', host: '{bar<>>}'), '/', '{bar}', [], ['bar' => '>']];
+        yield [new Route('/', [], ['bar' => '\d+'], host: '{bar<.*>}'), '/', '{bar}', [], ['bar' => '.*']];
+        yield [new Route('/', host: '{bar<[a-z]{2}>}'), '/', '{bar}', [], ['bar' => '[a-z]{2}']];
+
+        yield [new Route('/', host: '{bar<.*>?}'), '/', '{bar}', ['bar' => null], ['bar' => '.*']];
+        yield [new Route('/', host: '{bar<>>?<>}'), '/', '{bar}', ['bar' => '<>'], ['bar' => '>']];
     }
 
     /**