--- /dev/null
+<?php
+
+namespace Drupal\link\Plugin\Validation\Constraint;
+
+use Symfony\Component\Validator\Constraint;
+
+/**
+ * Validation constraint for links receiving data allowed by its settings.
+ *
+ * @Constraint(
+ * id = "LinkType",
+ * label = @Translation("Link data valid for link type.", context = "Validation"),
+ * )
+ */
+class LinkTypeConstraint extends Constraint {
+
+ public $message = "The path '@uri' is invalid.";
+
+}