--- /dev/null
+<?php
+
+namespace Drupal\crop\Plugin\Validation\Constraint;
+
+use Symfony\Component\Validator\Constraint;
+
+/**
+ * Supports validating crop type machine name.
+ *
+ * @Constraint(
+ * id = "CropTypeMachineNameValidation",
+ * label = @Translation("Crop Type machine name", context = "Validation")
+ * )
+ */
+class CropTypeMachineNameValidationConstraint extends Constraint {
+
+ /**
+ * The default violation message.
+ *
+ * @var string
+ */
+ public $message = 'Invalid machine-readable name.';
+
+}