Fixed exception in Flex::getDirectories() if the first parameter is set

CHANGELOG.md

@@ -15,6 +15,7 @@
     * Fix for `avatar_url` provided by 3rd party providers
     * Fixed non standard `lang` code lengths in `Utils` and `Session` detection
     * Fixed saving a new object in Flex `SimpleStorage`
+    * Fixed exception in `Flex::getDirectories()` if the first parameter is set
 
 # v1.6.8
 ## 04/23/2019

system/src/Grav/Framework/Flex/Flex.php

@@ -91,7 +91,7 @@ class Flex implements \Countable
         // Return the directories in the given order.
         $directories = [];
         foreach ($types as $type) {
-            $directories = $this->types[$type] ?? null;
+            $directories[$type] = $this->types[$type] ?? null;
         }
 
         return $keepMissing ? $directories : array_filter($directories);