diff --git a/date/date_c.php b/date/date_c.php
index e6f059d24..bc9739da3 100644
--- a/date/date_c.php
+++ b/date/date_c.php
@@ -250,7 +250,7 @@ public static function getLastErrors(): array|false {}
     #[Pure]
     #[TentativeType]
     #[LanguageLevelTypeAware(['8.3' => 'DateTimeImmutable'], default: 'DateTimeImmutable|false')]
-    public function modify(#[LanguageLevelTypeAware(['8.0' => 'string'], default: '')] $modifier) {}
+    public function modify(#[LanguageLevelTypeAware(['8.0' => 'string'], default: '')] $modifier): DateTimeImmutable|false {}
 
     /**
      * (PHP 5 &gt;=5.5.0)<br/>
@@ -566,7 +566,7 @@ public function format(#[LanguageLevelTypeAware(['8.0' => 'string'], default: ''
      */
     #[TentativeType]
     #[LanguageLevelTypeAware(['8.2' => 'DateTime'], default: 'DateTime|false')]
-    public function modify(#[LanguageLevelTypeAware(['8.0' => 'string'], default: '')] $modifier) {}
+    public function modify(#[LanguageLevelTypeAware(['8.0' => 'string'], default: '')] $modifier): DateTime|false {}
 
     /**
      * Adds an amount of days, months, years, hours, minutes and seconds to a DateTime object
@@ -942,7 +942,7 @@ public function format(#[LanguageLevelTypeAware(['8.0' => 'string'], default: ''
      */
     #[TentativeType]
     #[LanguageLevelTypeAware(['8.3' => 'DateInterval'], default: 'DateInterval|false')]
-    public static function createFromDateString(#[LanguageLevelTypeAware(['8.0' => 'string'], default: '')] $datetime) {}
+    public static function createFromDateString(#[LanguageLevelTypeAware(['8.0' => 'string'], default: '')] $datetime): DateInterval|false {}
 
     #[TentativeType]
     public function __wakeup(): void {}