Fixes #1791.

framework/yii/db/ActiveQuery.php

@@ -249,9 +249,15 @@ class ActiveQuery extends Query implements ActiveQueryInterface
 
 		if (!empty($with)) {
 			foreach ($with as $name => $value) {
+				if (is_integer($name)) {
+					if (!in_array($value, $this->with, true) && !isset($this->with[$value])) {
+						$this->with[] = $value;
+					}
+				} elseif (!isset($this->with[$name])) {
 					$this->with[$name] = $value;
 				}
 			}
+		}
 
 		return $this;
 	}