diff --git a/packages/node-name-resolver/src/NodeNameResolver.php b/packages/node-name-resolver/src/NodeNameResolver.php
index 3a19b68d7b9..029c24887ca 100644
--- a/packages/node-name-resolver/src/NodeNameResolver.php
+++ b/packages/node-name-resolver/src/NodeNameResolver.php
@@ -26,7 +26,7 @@ final class NodeNameResolver
     /**
      * @var string
      */
-    public const FILE = 'file';
+    private const FILE = 'file';
 
     /**
      * @var NodeNameResolverInterface[]