diff --git a/src/pocketmine/nbt/tag/ListTag.php b/src/pocketmine/nbt/tag/ListTag.php
index b15ff8b19..c03fb0f7c 100644
--- a/src/pocketmine/nbt/tag/ListTag.php
+++ b/src/pocketmine/nbt/tag/ListTag.php
@@ -29,6 +29,7 @@ use pocketmine\nbt\NBT;
 
 class ListTag extends NamedTag implements \ArrayAccess, \Countable{
 
+	/** @var int */
 	private $tagType;
 
 	/**