diff --git a/src/File.php b/src/File.php
index 1d14ea23..3a0b8fb5 100644
--- a/src/File.php
+++ b/src/File.php
@@ -1167,10 +1167,7 @@ public function getAbsoluteSize()
         return $this->File->getAbsoluteSize();
     }
 
-    /**
-     * @return ValidationResult
-     */
-    public function validate()
+    public function validate(): ValidationResult
     {
         $result = ValidationResult::create();
         $this->File->validateFilename($result, $this->Name);
diff --git a/src/Folder.php b/src/Folder.php
index 1ccf8364..ab79f075 100644
--- a/src/Folder.php
+++ b/src/Folder.php
@@ -336,7 +336,7 @@ public function StripThumbnail()
         return null;
     }
 
-    public function validate()
+    public function validate(): ValidationResult
     {
         $result = ValidationResult::create();
         $this->extend('updateValidate', $result);