diff --git a/stubs/CoreGenericIterators.phpstub b/stubs/CoreGenericIterators.phpstub
index 34ad308d324..69966ca69c7 100644
--- a/stubs/CoreGenericIterators.phpstub
+++ b/stubs/CoreGenericIterators.phpstub
@@ -104,7 +104,7 @@ interface SeekableIterator extends Iterator {
 /**
  * @template-covariant TKey
  * @template-covariant TValue
- * @template TIterator as Traversable<TKey, TValue>
+ * @template-covariant TIterator as Traversable<TKey, TValue>
  *
  * @template-implements OuterIterator<TKey, TValue>
  *
@@ -132,9 +132,9 @@ class IteratorIterator implements OuterIterator {
 /**
  * @template TKey
  * @template TValue
- * @template TIterator as Traversable<TKey, TValue>
+ * @template TIterator as Iterator<TKey, TValue>
  *
- * @template-extends IteratorIterator<TKey, TValue>
+ * @template-extends IteratorIterator<TKey, TValue, TIterator>
  */
 class AppendIterator extends IteratorIterator {
     public function __construct(){}
@@ -319,10 +319,11 @@ class ArrayIterator implements SeekableIterator, ArrayAccess, Serializable, Coun
 /**
  * @template-covariant TKey
  * @template-covariant TValue
+ * @template-covariant TIterator as Traversable<TKey, TValue>
  *
- * @template-extends IteratorIterator<TKey, TValue>
+ * @template-extends IteratorIterator<TKey, TValue, TIterator>
  */
-class FilterIterator extends IteratorIterator {
+abstract class FilterIterator extends IteratorIterator {
     /** @return bool */
     abstract public function accept();
 
@@ -340,11 +341,12 @@ class FilterIterator extends IteratorIterator {
 /**
  * @template-covariant TKey
  * @template-covariant TValue
+ * @template-covariant TIterator as Iterator<TKey, TValue>
  *
  * @template-implements OuterIterator<TKey, TValue>
  * @template-implements ArrayAccess<TKey, TValue>
  *
- * @template-extends IteratorIterator<TKey, TValue>
+ * @template-extends IteratorIterator<TKey, TValue, TIterator>
  */
 class CachingIterator extends IteratorIterator implements OuterIterator , ArrayAccess , Countable  {
     const CALL_TOSTRING = 1 ;
@@ -355,7 +357,7 @@ class CachingIterator extends IteratorIterator implements OuterIterator , ArrayA
     const FULL_CACHE = 256 ;
     
     /**
-     * @param Iterator<TKey, TValue> $iterator
+     * @param TIterator $iterator
      * @param int-mask-of<self::*> $flags
      */
     public function __construct(Iterator $iterator, int $flags = self::CALL_TOSTRING) {}
@@ -379,15 +381,16 @@ class CachingIterator extends IteratorIterator implements OuterIterator , ArrayA
 /**
  * @template-covariant TKey
  * @template-covariant TValue
+ * @template-covariant TIterator as Iterator<TKey, TValue>
  *
  * @template-implements OuterIterator<TKey, TValue>
  *
- * @template-extends FilterIterator<TKey, TValue>
+ * @template-extends FilterIterator<TKey, TValue, TIterator>
  */
 class CallbackFilterIterator extends FilterIterator implements OuterIterator  {
     /**
-     * @param Iterator<TKey, TValue> $iterator
-     * @param callable(TValue, TKey, Iterator<TKey, TValue>): bool $callback
+     * @param TIterator $iterator
+     * @param callable(TValue, TKey, TIterator): bool $callback
      */
     public function __construct(Iterator $iterator, callable $callback) {}
 
@@ -527,12 +530,13 @@ class GlobIterator extends FilesystemIterator implements Countable {
 /**
  * @template-covariant TKey
  * @template-covariant TValue
+ * @template-covariant TIterator as Iterator<TKey, TValue>
  *
- * @template-extends IteratorIterator<TKey, TValue>
+ * @template-extends IteratorIterator<TKey, TValue, TIterator>
  */
 class InfiniteIterator extends IteratorIterator {
     /**
-     * @param Iterator<TKey, TValue> $iterator
+     * @param TIterator $iterator
      */
     public function __construct(Iterator $iterator) {}
 
@@ -552,14 +556,15 @@ class InfiniteIterator extends IteratorIterator {
 /**
  * @template-covariant TKey
  * @template-covariant TValue
+ * @template-covariant TIterator as Iterator<TKey, TValue>
  *
  * @template-implements OuterIterator<TKey, TValue>
  *
- * @template-extends IteratorIterator<TKey, TValue>
+ * @template-extends IteratorIterator<TKey, TValue, TIterator>
  */
 class LimitIterator extends IteratorIterator implements OuterIterator {
     /**
-     * @param Iterator<TKey, TValue> $iterator
+     * @param TIterator $iterator
      */
     public function __construct(Iterator $iterator, int $offset = 0, int $count = -1) {}
 
@@ -581,12 +586,13 @@ class LimitIterator extends IteratorIterator implements OuterIterator {
 /**
  * @template-covariant TKey
  * @template-covariant TValue
+ * @template-covariant TIterator as Iterator<TKey, TValue>
  *
- * @template-extends IteratorIterator<TKey, TValue>
+ * @template-extends IteratorIterator<TKey, TValue, TIterator>
  */
 class NoRewindIterator extends IteratorIterator {
     /**
-     * @param Iterator<TKey, TValue> $iterator
+     * @param TIterator $iterator
      */
     public function __construct(Iterator $iterator) {}
 
@@ -668,18 +674,19 @@ class MultipleIterator implements Iterator {
 /**
  * @template TKey
  * @template TValue
+ * @template TIterator as RecursiveIterator<TKey, TValue>
  *
- * @template-extends FilterIterator<TKey, TValue>
+ * @template-extends FilterIterator<TKey, TValue, TIterator>
  * @template-implements RecursiveIterator<TKey, TValue>
  */
 abstract class RecursiveFilterIterator extends FilterIterator implements RecursiveIterator {
 
     /**
-     * @param RecursiveIterator<TKey, TValue> $iterator
+     * @param TIterator $iterator
      */
     public function __construct(RecursiveIterator $iterator) {}
     /**
-     * @return RecursiveFilterIterator<TKey, TValue>
+     * @return TIterator
      */
     public function getChildren() {}
 
@@ -704,8 +711,9 @@ abstract class RecursiveFilterIterator extends FilterIterator implements Recursi
 /**
  * @template TKey
  * @template TValue
+ * @template TIterator as RecursiveIterator<TKey, TValue>
  *
- * @template-extends RecursiveFilterIterator<TKey, TValue>
+ * @template-extends RecursiveFilterIterator<TKey, TValue, TIterator>
  */
 class ParentIterator extends RecursiveFilterIterator implements RecursiveIterator, OuterIterator {
 
@@ -714,7 +722,7 @@ class ParentIterator extends RecursiveFilterIterator implements RecursiveIterato
      */
     public function accept() {}
     /**
-     * @param RecursiveIterator<TKey, TValue> $iterator
+     * @param TIterator $iterator
      */
     public function __construct(RecursiveIterator $iterator) {}
     /**
@@ -785,9 +793,10 @@ class RecursiveArrayIterator extends ArrayIterator implements RecursiveIterator
 /**
  * @template TKey
  * @template TValue
+ * @template TIterator as Iterator<TKey, TValue>
  *
  * @template-implements RecursiveIterator<TKey, TValue>
- * @template-extends ArrayIterator<TKey, TValue>
+ * @template-extends CachingIterator<TKey, TValue, TIterator>
  */
 class RecursiveCachingIterator extends CachingIterator implements RecursiveIterator {
 
@@ -799,12 +808,12 @@ class RecursiveCachingIterator extends CachingIterator implements RecursiveItera
     const FULL_CACHE = 256 ;
 
     /**
-     * @param Iterator<TKey, TValue> $iterator
+     * @param TIterator $iterator
      * @param int-mask-of<self::*> $flags
      */
     public function __construct(Iterator $iterator, int $flags = 0) {}
     /**
-     * @return RecursiveCachingIterator<TKey,TValue>
+     * @return RecursiveCachingIterator<TKey,TValue, TIterator>
      */
     public function getChildren() {}
 
@@ -829,19 +838,20 @@ class RecursiveCachingIterator extends CachingIterator implements RecursiveItera
 /**
  * @template TKey
  * @template TValue
+ * @template TIterator as RecursiveIterator<TKey, TValue>
  *
  * @template-implements RecursiveIterator<TKey, TValue>
- * @template-extends CallbackFilterIterator<TKey, TValue>
+ * @template-extends CallbackFilterIterator<TKey, TValue, TIterator>
  */
 class RecursiveCallbackFilterIterator extends CallbackFilterIterator implements RecursiveIterator {
 
     /**
-     * @param RecursiveIterator<TKey, TValue> $iterator
-     * @param callable(TValue, TKey, RecursiveIterator<TKey, TValue>): bool $callback
+     * @param TIterator $iterator
+     * @param callable(TValue, TKey, TIterator): bool $callback
      */
     public function __construct(RecursiveIterator $iterator, callable $callback) {}
     /**
-     * @return RecursiveCallbackFilterIterator<TKey, TValue>
+     * @return RecursiveCallbackFilterIterator<TKey, TValue, TIterator>
      */
     public function getChildren() {}
 
@@ -926,9 +936,10 @@ class RecursiveIteratorIterator implements OuterIterator {
 /**
  * @template TKey
  * @template TValue
+ * @template TIterator as RecursiveIterator<TKey, TValue>
  *
  * @template-implements RecursiveIterator<TKey, TValue>
- * @template-extends RegexIterator<TKey, TValue>
+ * @template-extends RegexIterator<TKey, TValue, TIterator>
  */
 class RecursiveRegexIterator extends RegexIterator implements RecursiveIterator {
 
@@ -940,7 +951,7 @@ class RecursiveRegexIterator extends RegexIterator implements RecursiveIterator
     const USE_KEY = 1 ;
 
     /**
-     * @param RecursiveIterator<TKey, TValue> $iterator
+     * @param TIterator $iterator
      * @param string $regex
      * @param self::MATH|self::GET_MATCH|self::ALL_MATCHES|self::SPLIT|self::REPLACE $mode
      * @param self::USE_KEY|0 $flags
@@ -1063,8 +1074,9 @@ class RecursiveTreeIterator extends RecursiveIteratorIterator implements OuterIt
 /**
  * @template TKey
  * @template TValue
+ * @template TIterator as Iterator<TKey, TValue>
  *
- * @template-extends FilterIterator<TKey, TValue>
+ * @template-extends FilterIterator<TKey, TValue, TIterator>
  */
 class RegexIterator extends FilterIterator {
     const MATCH = 0 ;
@@ -1075,7 +1087,7 @@ class RegexIterator extends FilterIterator {
     const USE_KEY = 1 ;
 
     /**
-     * @param Iterator<TKey, TValue> $iterator
+     * @param TIterator $iterator
      * @param string $regex
      * @param self::MATCH|self::GET_MATCH|self::ALL_MATCHES|self::SPLIT|self::REPLACE $mode
      * @param int-mask<self::USE_KEY> $flags
diff --git a/tests/GeneratorTest.php b/tests/GeneratorTest.php
index 12ca3020f04..1090b47faec 100644
--- a/tests/GeneratorTest.php
+++ b/tests/GeneratorTest.php
@@ -287,7 +287,7 @@ function generator(): Generator
                     $iterator = new NoRewindIterator(generator());
                     ',
                 'assertions' => [
-                    '$iterator' => 'NoRewindIterator<int, string>',
+                    '$iterator' => 'NoRewindIterator<int, string, Generator<int, string, mixed, mixed>>',
                 ]
             ],
             'detectYieldInNew' => [
diff --git a/tests/Template/ClassTemplateExtendsTest.php b/tests/Template/ClassTemplateExtendsTest.php
index a5c45901c5d..85531986aba 100644
--- a/tests/Template/ClassTemplateExtendsTest.php
+++ b/tests/Template/ClassTemplateExtendsTest.php
@@ -3670,7 +3670,7 @@ public function foo(int $i): Container
                      * @template-covariant TKey
                      * @template-covariant TValue
                      *
-                     * @template-extends IteratorIterator<TKey, TValue, Traversable<TKey, TValue>>
+                     * @template-extends IteratorIterator<TKey, TValue, Iterator<TKey, TValue>>
                      */
                     abstract class MyFilterIterator extends IteratorIterator {
                          /** @return bool */