diff --git a/src/Symfony/Component/ErrorHandler/DebugClassLoader.php b/src/Symfony/Component/ErrorHandler/DebugClassLoader.php
index 6e4adeab05509..746e8d44a548e 100644
--- a/src/Symfony/Component/ErrorHandler/DebugClassLoader.php
+++ b/src/Symfony/Component/ErrorHandler/DebugClassLoader.php
@@ -56,7 +56,7 @@ class DebugClassLoader
         'null' => 'null',
         'resource' => 'resource',
         'boolean' => 'bool',
-        'true' => 'bool',
+        'true' => 'true',
         'false' => 'false',
         'integer' => 'int',
         'array' => 'array',
@@ -74,6 +74,7 @@ class DebugClassLoader
         '$this' => 'static',
         'list' => 'array',
         'class-string' => 'string',
+        'never' => 'never',
     ];
 
     private const BUILTIN_RETURN_TYPES = [
@@ -91,6 +92,9 @@ class DebugClassLoader
         'parent' => true,
         'mixed' => true,
         'static' => true,
+        'null' => true,
+        'true' => true,
+        'never' => true,
     ];
 
     private const MAGIC_METHODS = [
@@ -762,6 +766,12 @@ private function setReturnType(string $types, string $class, string $method, str
             return;
         }
 
+        if ('null' === $types) {
+            self::$returnTypes[$class][$method] = ['null', 'null', $class, $filename];
+
+            return;
+        }
+
         if ($nullable = 0 === strpos($types, 'null|')) {
             $types = substr($types, 5);
         } elseif ($nullable = '|null' === substr($types, -5)) {
diff --git a/src/Symfony/Component/ErrorHandler/Tests/DebugClassLoaderTest.php b/src/Symfony/Component/ErrorHandler/Tests/DebugClassLoaderTest.php
index 92ff96fdf83eb..83d7793d89592 100644
--- a/src/Symfony/Component/ErrorHandler/Tests/DebugClassLoaderTest.php
+++ b/src/Symfony/Component/ErrorHandler/Tests/DebugClassLoaderTest.php
@@ -402,6 +402,10 @@ class_exists('Test\\'.ReturnType::class, true);
             'Method "Symfony\Component\ErrorHandler\Tests\Fixtures\ReturnTypeParent::mixed()" might add "mixed" as a native return type declaration in the future. Do the same in child class "Test\Symfony\Component\ErrorHandler\Tests\ReturnType" now to avoid errors or add an explicit @return annotation to suppress this message.',
             'Method "Symfony\Component\ErrorHandler\Tests\Fixtures\ReturnTypeParent::nullableMixed()" might add "mixed" as a native return type declaration in the future. Do the same in child class "Test\Symfony\Component\ErrorHandler\Tests\ReturnType" now to avoid errors or add an explicit @return annotation to suppress this message.',
             'Method "Symfony\Component\ErrorHandler\Tests\Fixtures\ReturnTypeParent::static()" might add "static" as a native return type declaration in the future. Do the same in child class "Test\Symfony\Component\ErrorHandler\Tests\ReturnType" now to avoid errors or add an explicit @return annotation to suppress this message.',
+            'Method "Symfony\Component\ErrorHandler\Tests\Fixtures\ReturnTypeParent::false()" might add "false" as a native return type declaration in the future. Do the same in child class "Test\Symfony\Component\ErrorHandler\Tests\ReturnType" now to avoid errors or add an explicit @return annotation to suppress this message.',
+            'Method "Symfony\Component\ErrorHandler\Tests\Fixtures\ReturnTypeParent::true()" might add "true" as a native return type declaration in the future. Do the same in child class "Test\Symfony\Component\ErrorHandler\Tests\ReturnType" now to avoid errors or add an explicit @return annotation to suppress this message.',
+            'Method "Symfony\Component\ErrorHandler\Tests\Fixtures\ReturnTypeParent::never()" might add "never" as a native return type declaration in the future. Do the same in child class "Test\Symfony\Component\ErrorHandler\Tests\ReturnType" now to avoid errors or add an explicit @return annotation to suppress this message.',
+            'Method "Symfony\Component\ErrorHandler\Tests\Fixtures\ReturnTypeParent::null()" might add "null" as a native return type declaration in the future. Do the same in child class "Test\Symfony\Component\ErrorHandler\Tests\ReturnType" now to avoid errors or add an explicit @return annotation to suppress this message.',
         ]), $deprecations);
     }
 }
diff --git a/src/Symfony/Component/ErrorHandler/Tests/Fixtures/ReturnType.php b/src/Symfony/Component/ErrorHandler/Tests/Fixtures/ReturnType.php
index 21c4d2012f663..1b8138001de78 100644
--- a/src/Symfony/Component/ErrorHandler/Tests/Fixtures/ReturnType.php
+++ b/src/Symfony/Component/ErrorHandler/Tests/Fixtures/ReturnType.php
@@ -46,5 +46,9 @@ public function this() { }
     public function mixed() { }
     public function nullableMixed() { }
     public function static() { }
+    public function false() { }
+    public function true() { }
+    public function never() { }
+    public function null() { }
     public function outsideMethod() { }
 }
diff --git a/src/Symfony/Component/ErrorHandler/Tests/Fixtures/ReturnTypeParent.php b/src/Symfony/Component/ErrorHandler/Tests/Fixtures/ReturnTypeParent.php
index c7b0b6f0fca0c..d42c7c8c02167 100644
--- a/src/Symfony/Component/ErrorHandler/Tests/Fixtures/ReturnTypeParent.php
+++ b/src/Symfony/Component/ErrorHandler/Tests/Fixtures/ReturnTypeParent.php
@@ -220,6 +220,34 @@ public function static()
     {
     }
 
+    /**
+     * @return false
+     */
+    public function false()
+    {
+    }
+
+    /**
+     * @return true
+     */
+    public function true()
+    {
+    }
+
+    /**
+     * @return never
+     */
+    public function never()
+    {
+    }
+
+    /**
+     * @return null
+     */
+    public function null()
+    {
+    }
+
     /**
      * @return int
      */