diff --git a/src/Symfony/Bundle/FrameworkBundle/composer.json b/src/Symfony/Bundle/FrameworkBundle/composer.json
index 78d7ae1e564e..40cff711ae8a 100644
--- a/src/Symfony/Bundle/FrameworkBundle/composer.json
+++ b/src/Symfony/Bundle/FrameworkBundle/composer.json
@@ -22,6 +22,7 @@
         "symfony/class-loader": "~3.2",
         "symfony/dependency-injection": "^3.4.24|^4.2.5",
         "symfony/config": "~3.4|~4.0",
+        "symfony/debug": "~2.8|~3.0|~4.0",
         "symfony/event-dispatcher": "~3.4|~4.0",
         "symfony/http-foundation": "^3.3.11|~4.0",
         "symfony/http-kernel": "~3.4|~4.0",
diff --git a/src/Symfony/Bundle/TwigBundle/composer.json b/src/Symfony/Bundle/TwigBundle/composer.json
index 5d27f06ff92b..4cc08e1b35b2 100644
--- a/src/Symfony/Bundle/TwigBundle/composer.json
+++ b/src/Symfony/Bundle/TwigBundle/composer.json
@@ -18,6 +18,7 @@
     "require": {
         "php": "^5.5.9|>=7.0.8",
         "symfony/config": "~3.2|~4.0",
+        "symfony/debug": "~2.8|~3.0|~4.0",
         "symfony/twig-bridge": "^3.4.3|^4.0.3",
         "symfony/http-foundation": "~2.8|~3.0|~4.0",
         "symfony/http-kernel": "^3.3|~4.0",
diff --git a/src/Symfony/Component/Debug/Tests/FatalErrorHandler/ClassNotFoundFatalErrorHandlerTest.php b/src/Symfony/Component/Debug/Tests/FatalErrorHandler/ClassNotFoundFatalErrorHandlerTest.php
index 8e615ac640be..112dfbb7f752 100644
--- a/src/Symfony/Component/Debug/Tests/FatalErrorHandler/ClassNotFoundFatalErrorHandlerTest.php
+++ b/src/Symfony/Component/Debug/Tests/FatalErrorHandler/ClassNotFoundFatalErrorHandlerTest.php
@@ -61,7 +61,7 @@ public function testHandleClassNotFound($error, $translatedMessage, $autoloader
         }
 
         $this->assertInstanceOf('Symfony\Component\Debug\Exception\ClassNotFoundException', $exception);
-        $this->assertSame($translatedMessage, $exception->getMessage());
+        $this->assertRegExp($translatedMessage, $exception->getMessage());
         $this->assertSame($error['type'], $exception->getSeverity());
         $this->assertSame($error['file'], $exception->getFile());
         $this->assertSame($error['line'], $exception->getLine());
@@ -82,7 +82,7 @@ public function provideClassNotFoundData()
                     'file' => 'foo.php',
                     'message' => 'Class \'WhizBangFactory\' not found',
                 ],
-                "Attempted to load class \"WhizBangFactory\" from the global namespace.\nDid you forget a \"use\" statement?",
+                "/^Attempted to load class \"WhizBangFactory\" from the global namespace.\nDid you forget a \"use\" statement\?$/",
             ],
             [
                 [
@@ -91,7 +91,7 @@ public function provideClassNotFoundData()
                     'file' => 'foo.php',
                     'message' => 'Class \'Foo\\Bar\\WhizBangFactory\' not found',
                 ],
-                "Attempted to load class \"WhizBangFactory\" from namespace \"Foo\\Bar\".\nDid you forget a \"use\" statement for another namespace?",
+                "/^Attempted to load class \"WhizBangFactory\" from namespace \"Foo\\\\Bar\".\nDid you forget a \"use\" statement for another namespace\?$/",
             ],
             [
                 [
@@ -100,7 +100,7 @@ public function provideClassNotFoundData()
                     'file' => 'foo.php',
                     'message' => 'Class \'UndefinedFunctionException\' not found',
                 ],
-                "Attempted to load class \"UndefinedFunctionException\" from the global namespace.\nDid you forget a \"use\" statement for \"Symfony\Component\Debug\Exception\UndefinedFunctionException\"?",
+                "/^Attempted to load class \"UndefinedFunctionException\" from the global namespace.\nDid you forget a \"use\" statement for .*\"Symfony\\\\Component\\\\Debug\\\\Exception\\\\UndefinedFunctionException\"\?$/",
             ],
             [
                 [
@@ -109,7 +109,7 @@ public function provideClassNotFoundData()
                     'file' => 'foo.php',
                     'message' => 'Class \'PEARClass\' not found',
                 ],
-                "Attempted to load class \"PEARClass\" from the global namespace.\nDid you forget a \"use\" statement for \"Symfony_Component_Debug_Tests_Fixtures_PEARClass\"?",
+                "/^Attempted to load class \"PEARClass\" from the global namespace.\nDid you forget a \"use\" statement for \"Symfony_Component_Debug_Tests_Fixtures_PEARClass\"\?$/",
             ],
             [
                 [
@@ -118,7 +118,7 @@ public function provideClassNotFoundData()
                     'file' => 'foo.php',
                     'message' => 'Class \'Foo\\Bar\\UndefinedFunctionException\' not found',
                 ],
-                "Attempted to load class \"UndefinedFunctionException\" from namespace \"Foo\Bar\".\nDid you forget a \"use\" statement for \"Symfony\Component\Debug\Exception\UndefinedFunctionException\"?",
+                "/^Attempted to load class \"UndefinedFunctionException\" from namespace \"Foo\\\\Bar\".\nDid you forget a \"use\" statement for .*\"Symfony\\\\Component\\\\Debug\\\\Exception\\\\UndefinedFunctionException\"\?$/",
             ],
             [
                 [
@@ -127,7 +127,7 @@ public function provideClassNotFoundData()
                     'file' => 'foo.php',
                     'message' => 'Class \'Foo\\Bar\\UndefinedFunctionException\' not found',
                 ],
-                "Attempted to load class \"UndefinedFunctionException\" from namespace \"Foo\Bar\".\nDid you forget a \"use\" statement for \"Symfony\Component\Debug\Exception\UndefinedFunctionException\"?",
+                "/^Attempted to load class \"UndefinedFunctionException\" from namespace \"Foo\\\\Bar\".\nDid you forget a \"use\" statement for \"Symfony\\\\Component\\\\Debug\\\\Exception\\\\UndefinedFunctionException\"\?$/",
                 [$autoloader, 'loadClass'],
             ],
             [
@@ -137,7 +137,7 @@ public function provideClassNotFoundData()
                     'file' => 'foo.php',
                     'message' => 'Class \'Foo\\Bar\\UndefinedFunctionException\' not found',
                 ],
-                "Attempted to load class \"UndefinedFunctionException\" from namespace \"Foo\Bar\".\nDid you forget a \"use\" statement for \"Symfony\Component\Debug\Exception\UndefinedFunctionException\"?",
+                "/^Attempted to load class \"UndefinedFunctionException\" from namespace \"Foo\\\\Bar\".\nDid you forget a \"use\" statement for \"Symfony\\\\Component\\\\Debug\\\\Exception\\\\UndefinedFunctionException\"\?/",
                 [$debugClassLoader, 'loadClass'],
             ],
             [
@@ -147,7 +147,7 @@ public function provideClassNotFoundData()
                     'file' => 'foo.php',
                     'message' => 'Class \'Foo\\Bar\\UndefinedFunctionException\' not found',
                 ],
-                "Attempted to load class \"UndefinedFunctionException\" from namespace \"Foo\\Bar\".\nDid you forget a \"use\" statement for another namespace?",
+                "/^Attempted to load class \"UndefinedFunctionException\" from namespace \"Foo\\\\Bar\".\nDid you forget a \"use\" statement for another namespace\?$/",
                 function ($className) { /* do nothing here */ },
             ],
         ];