diff --git a/src/Extension/CoreExtension.php b/src/Extension/CoreExtension.php
index accad4ebc55..62ce17012b1 100644
--- a/src/Extension/CoreExtension.php
+++ b/src/Extension/CoreExtension.php
@@ -1499,7 +1499,7 @@ function twig_array_batch($items, $size, $fill = null)
  * @param mixed  $object            The object or array from where to get the item
  * @param mixed  $item              The item to get from the array or object
  * @param array  $arguments         An array of arguments to pass if the item is an object method
- * @param string $type              The type of attribute (@see \Twig_Template constants)
+ * @param string $type              The type of attribute (@see \Twig\Template constants)
  * @param bool   $isDefinedTest     Whether this is only a defined check
  * @param bool   $ignoreStrictCheck Whether to ignore the strict attribute check or not
  *
@@ -1581,7 +1581,7 @@ function twig_get_attribute(Environment $env, Source $source, $object, $item, ar
     }
 
     if ($object instanceof Template) {
-        throw new RuntimeError('Accessing \Twig_Template attributes is forbidden.');
+        throw new RuntimeError('Accessing \Twig\Template attributes is forbidden.');
     }
 
     // object property
diff --git a/src/ExtensionSet.php b/src/ExtensionSet.php
index 3fd7ba2f833..63d360f3208 100644
--- a/src/ExtensionSet.php
+++ b/src/ExtensionSet.php
@@ -90,7 +90,7 @@ public function hasExtension($class)
      *
      * @param string $class The extension class name
      *
-     * @return ExtensionInterface A \Twig_ExtensionInterface instance
+     * @return ExtensionInterface
      */
     public function getExtension($class)
     {
@@ -195,7 +195,7 @@ public function getFunctions()
      *
      * @param string $name function name
      *
-     * @return TwigFunction|false A \Twig_Function instance or false if the function does not exist
+     * @return TwigFunction|false
      */
     public function getFunction($name)
     {
@@ -258,7 +258,7 @@ public function getFilters()
      *
      * @param string $name The filter name
      *
-     * @return TwigFilter|false A \Twig_Filter instance or false if the filter does not exist
+     * @return TwigFilter|false
      */
     public function getFilter($name)
     {
@@ -381,7 +381,7 @@ public function getTests()
      *
      * @param string $name The test name
      *
-     * @return TwigTest|false A \Twig_Test instance or false if the test does not exist
+     * @return TwigTest|false
      */
     public function getTest($name)
     {
@@ -475,7 +475,7 @@ private function initExtension(ExtensionInterface $extension)
         // token parsers
         foreach ($extension->getTokenParsers() as $parser) {
             if (!$parser instanceof TokenParserInterface) {
-                throw new \LogicException('getTokenParsers() must return an array of \Twig_TokenParserInterface.');
+                throw new \LogicException('getTokenParsers() must return an array of \Twig\TokenParser\TokenParserInterface.');
             }
 
             $this->parsers[] = $parser;
diff --git a/src/Node/Expression/CallExpression.php b/src/Node/Expression/CallExpression.php
index a32e37b09ca..de1738fb22a 100644
--- a/src/Node/Expression/CallExpression.php
+++ b/src/Node/Expression/CallExpression.php
@@ -40,7 +40,7 @@ protected function compileCallable(Compiler $compiler)
                 // For BC/FC with namespaced aliases
                 $class = (new \ReflectionClass(\get_class($callable[0])))->name;
                 if (!$compiler->getEnvironment()->hasExtension($class)) {
-                    // Compile a non-optimized call to trigger a \Twig_Error_Runtime, which cannot be a compile-time error
+                    // Compile a non-optimized call to trigger a \Twig\Error\RuntimeError, which cannot be a compile-time error
                     $compiler->raw(sprintf('$this->env->getExtension(\'%s\')', $class));
                 } else {
                     $compiler->raw(sprintf('$this->extensions[\'%s\']', ltrim($class, '\\')));
diff --git a/src/Node/Node.php b/src/Node/Node.php
index 5f22425dfb0..ff9ced0c0ad 100644
--- a/src/Node/Node.php
+++ b/src/Node/Node.php
@@ -43,7 +43,7 @@ public function __construct(array $nodes = [], array $attributes = [], $lineno =
     {
         foreach ($nodes as $name => $node) {
             if (!$node instanceof self) {
-                throw new \InvalidArgumentException(sprintf('Using "%s" for the value of node "%s" of "%s" is not supported. You must pass a \Twig_Node instance.', \is_object($node) ? \get_class($node) : null === $node ? 'null' : \gettype($node), $name, \get_class($this)));
+                throw new \InvalidArgumentException(sprintf('Using "%s" for the value of node "%s" of "%s" is not supported. You must pass a \Twig\Node\Node instance.', \is_object($node) ? \get_class($node) : null === $node ? 'null' : \gettype($node), $name, \get_class($this)));
             }
         }
         $this->nodes = $nodes;