diff --git a/core/lib/Drupal/Core/Validation/Plugin/Validation/Constraint/AllowedValuesConstraintValidator.php b/core/lib/Drupal/Core/Validation/Plugin/Validation/Constraint/AllowedValuesConstraintValidator.php
index c8ff90e..fb1150b 100644
--- a/core/lib/Drupal/Core/Validation/Plugin/Validation/Constraint/AllowedValuesConstraintValidator.php
+++ b/core/lib/Drupal/Core/Validation/Plugin/Validation/Constraint/AllowedValuesConstraintValidator.php
@@ -37,6 +37,60 @@ public function validate($value, Constraint $constraint) {
         $value = $typed_data->get($name)->getValue();
       }
     }
-    return parent::validate($value, $constraint);
+
+    // Start to validate. The only difference from parent::validate() is
+    // code checks $value before checks $constraint->choices here. We do this
+    // to make sure $value is checked firstly.
+    if (null === $value) {
+      return;
+    }
+
+    if (!$constraint->choices && !$constraint->callback) {
+      throw new ConstraintDefinitionException('Either "choices" or "callback" must be specified on constraint Choice');
+    }
+
+    if ($constraint->multiple && !is_array($value)) {
+      throw new UnexpectedTypeException($value, 'array');
+    }
+
+    if ($constraint->callback) {
+      if (is_callable(array($this->context->getClassName(), $constraint->callback))) {
+        $choices = call_user_func(array($this->context->getClassName(), $constraint->callback));
+      }
+      elseif (is_callable($constraint->callback)) {
+        $choices = call_user_func($constraint->callback);
+      }
+      else {
+        throw new ConstraintDefinitionException('The Choice constraint expects a valid callback');
+      }
+    }
+    else {
+      $choices = $constraint->choices;
+    }
+
+    if ($constraint->multiple) {
+      foreach ($value as $_value) {
+        if (!in_array($_value, $choices, $constraint->strict)) {
+          $this->context->addViolation($constraint->multipleMessage, array('{{ value }}' => $_value));
+        }
+      }
+
+      $count = count($value);
+
+      if ($constraint->min !== null && $count < $constraint->min) {
+        $this->context->addViolation($constraint->minMessage, array('{{ limit }}' => $constraint->min), null, (int) $constraint->min);
+
+        return;
+      }
+
+      if ($constraint->max !== null && $count > $constraint->max) {
+        $this->context->addViolation($constraint->maxMessage, array('{{ limit }}' => $constraint->max), null, (int) $constraint->max);
+
+        return;
+      }
+    }
+    elseif (!in_array($value, $choices, $constraint->strict)) {
+      $this->context->addViolation($constraint->message, array('{{ value }}' => $value));
+    }
   }
 }