diff --git a/src/NodeVisitor/EscaperNodeVisitor.php b/src/NodeVisitor/EscaperNodeVisitor.php
index aa8df91a2..fafceb4db 100644
--- a/src/NodeVisitor/EscaperNodeVisitor.php
+++ b/src/NodeVisitor/EscaperNodeVisitor.php
@@ -29,6 +29,8 @@ use Twig\NodeTraverser;
 
 /**
  * @author Fabien Potencier <fabien@symfony.com>
+ *
+ * @internal
  */
 final class EscaperNodeVisitor implements NodeVisitorInterface
 {
diff --git a/src/NodeVisitor/MacroAutoImportNodeVisitor.php b/src/NodeVisitor/MacroAutoImportNodeVisitor.php
index 4c717faf8..af477e653 100644
--- a/src/NodeVisitor/MacroAutoImportNodeVisitor.php
+++ b/src/NodeVisitor/MacroAutoImportNodeVisitor.php
@@ -23,6 +23,8 @@ use Twig\Node\Node;
 
 /**
  * @author Fabien Potencier <fabien@symfony.com>
+ *
+ * @internal
  */
 final class MacroAutoImportNodeVisitor implements NodeVisitorInterface
 {
diff --git a/src/NodeVisitor/OptimizerNodeVisitor.php b/src/NodeVisitor/OptimizerNodeVisitor.php
index c8eb1625d..c167d2633 100644
--- a/src/NodeVisitor/OptimizerNodeVisitor.php
+++ b/src/NodeVisitor/OptimizerNodeVisitor.php
@@ -34,6 +34,8 @@ use Twig\Node\PrintNode;
  * optimizer mode.
  *
  * @author Fabien Potencier <fabien@symfony.com>
+ *
+ * @internal
  */
 final class OptimizerNodeVisitor implements NodeVisitorInterface
 {
diff --git a/src/NodeVisitor/SafeAnalysisNodeVisitor.php b/src/NodeVisitor/SafeAnalysisNodeVisitor.php
index 95fc652de..90d6f2e0f 100644
--- a/src/NodeVisitor/SafeAnalysisNodeVisitor.php
+++ b/src/NodeVisitor/SafeAnalysisNodeVisitor.php
@@ -23,6 +23,9 @@ use Twig\Node\Expression\NameExpression;
 use Twig\Node\Expression\ParentExpression;
 use Twig\Node\Node;
 
+/**
+ * @internal
+ */
 final class SafeAnalysisNodeVisitor implements NodeVisitorInterface
 {
     private $data = [];
diff --git a/src/NodeVisitor/SandboxNodeVisitor.php b/src/NodeVisitor/SandboxNodeVisitor.php
index 24a37aa51..1446cee6b 100644
--- a/src/NodeVisitor/SandboxNodeVisitor.php
+++ b/src/NodeVisitor/SandboxNodeVisitor.php
@@ -28,6 +28,8 @@ use Twig\Node\SetNode;
 
 /**
  * @author Fabien Potencier <fabien@symfony.com>
+ *
+ * @internal
  */
 final class SandboxNodeVisitor implements NodeVisitorInterface
 {