diff --git a/framework/CHANGELOG.md b/framework/CHANGELOG.md
index 1a4fee3469..671d6786d3 100644
--- a/framework/CHANGELOG.md
+++ b/framework/CHANGELOG.md
@@ -71,6 +71,7 @@ Yii Framework 2 Change Log
 - Bug #20636: Fix `@param` annotations for `$message` in logging methods (mspirkov)
 - Bug #20637: Fix PHPDoc annotations in `ActiveRelationTrait`. Add PHPStan/Psalm annotations for `$modelClass` in `ActiveQuery`, `ActiveQueryTrait` and `ActiveRelationTrait` (mspirkov)
 - Bug #20639: Add missing generics in `yii\web` namespace (mspirkov)
+- Bug #20645: Add missing generics in `yii\helpers` and `yii\test` namespaces. Fix PHPDoc annotations in `ArrayAccessTrait` (mspirkov)
 - Bug #20640: Fix `@param` annotation for `$block` in `yii\console\Markdown::renderParagraph()` (mspirkov)
 
 
diff --git a/framework/base/ArrayAccessTrait.php b/framework/base/ArrayAccessTrait.php
index 177894e554..6d16bf613a 100644
--- a/framework/base/ArrayAccessTrait.php
+++ b/framework/base/ArrayAccessTrait.php
@@ -17,6 +17,9 @@ namespace yii\base;
  *
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
+ *
+ * @phpstan-property array<array-key, mixed> $data
+ * @psalm-property array<array-key, mixed> $data
  */
 trait ArrayAccessTrait
 {
@@ -45,7 +48,7 @@ trait ArrayAccessTrait
 
     /**
      * This method is required by the interface [[\ArrayAccess]].
-     * @param mixed $offset the offset to check on
+     * @param int|string $offset the offset to check on
      * @return bool
      */
     #[\ReturnTypeWillChange]
@@ -56,7 +59,7 @@ trait ArrayAccessTrait
 
     /**
      * This method is required by the interface [[\ArrayAccess]].
-     * @param int $offset the offset to retrieve element.
+     * @param int|string $offset the offset to retrieve element.
      * @return mixed the element at the offset, null if no element is found at the offset
      */
     #[\ReturnTypeWillChange]
@@ -67,7 +70,7 @@ trait ArrayAccessTrait
 
     /**
      * This method is required by the interface [[\ArrayAccess]].
-     * @param int $offset the offset to set element
+     * @param int|string $offset the offset to set element
      * @param mixed $item the element value
      */
     #[\ReturnTypeWillChange]
@@ -78,7 +81,7 @@ trait ArrayAccessTrait
 
     /**
      * This method is required by the interface [[\ArrayAccess]].
-     * @param mixed $offset the offset to unset element
+     * @param int|string $offset the offset to unset element
      */
     #[\ReturnTypeWillChange]
     public function offsetUnset($offset)
diff --git a/framework/helpers/BaseArrayHelper.php b/framework/helpers/BaseArrayHelper.php
index 4f56d38f0c..546f60024c 100644
--- a/framework/helpers/BaseArrayHelper.php
+++ b/framework/helpers/BaseArrayHelper.php
@@ -628,6 +628,9 @@ class BaseArrayHelper
      * @param array|ArrayAccess $array the array with keys to check
      * @param bool $caseSensitive whether the key comparison should be case-sensitive
      * @return bool whether the array contains the specified key
+     *
+     * @phpstan-param array<array-key, mixed>|ArrayAccess<array-key, mixed> $array
+     * @psalm-param array<array-key, mixed>|ArrayAccess<array-key, mixed> $array
      */
     public static function keyExists($key, $array, $caseSensitive = true)
     {
diff --git a/framework/test/ArrayFixture.php b/framework/test/ArrayFixture.php
index c146ab34e3..55b48f505d 100644
--- a/framework/test/ArrayFixture.php
+++ b/framework/test/ArrayFixture.php
@@ -17,6 +17,9 @@ use yii\base\InvalidConfigException;
  *
  * @author Mark Jebri <mark.github@yandex.ru>
  * @since 2.0
+ *
+ * @implements \IteratorAggregate<string, array<string, mixed>>
+ * @implements \ArrayAccess<string, array<string, mixed>|null>
  */
 class ArrayFixture extends Fixture implements \IteratorAggregate, \ArrayAccess, \Countable
 {
@@ -25,6 +28,9 @@ class ArrayFixture extends Fixture implements \IteratorAggregate, \ArrayAccess,
 
     /**
      * @var array the data rows. Each array element represents one row of data (column name => column value).
+     *
+     * @phpstan-var array<string, array<string, mixed>>
+     * @psalm-var array<string, array<string, mixed>>
      */
     public $data = [];
 
@@ -48,6 +54,9 @@ class ArrayFixture extends Fixture implements \IteratorAggregate, \ArrayAccess,
      *
      * @return array the data to be put into the database
      * @throws InvalidConfigException if the specified data file does not exist.
+     *
+     * @phpstan-return array<string, array<string, mixed>>
+     * @psalm-return array<string, array<string, mixed>>
      */
     protected function getData()
     {
diff --git a/framework/test/BaseActiveFixture.php b/framework/test/BaseActiveFixture.php
index 0fb45dd483..a5b8d54aec 100644
--- a/framework/test/BaseActiveFixture.php
+++ b/framework/test/BaseActiveFixture.php
@@ -17,6 +17,9 @@ use yii\base\InvalidConfigException;
  *
  * @author Qiang Xue <qiang.xue@gmail.com>
  * @since 2.0
+ *
+ * @implements \IteratorAggregate<string, array<string, mixed>>
+ * @implements \ArrayAccess<string, array<string, mixed>|null>
  */
 abstract class BaseActiveFixture extends DbFixture implements \IteratorAggregate, \ArrayAccess, \Countable
 {
@@ -29,6 +32,9 @@ abstract class BaseActiveFixture extends DbFixture implements \IteratorAggregate
     public $modelClass;
     /**
      * @var array the data rows. Each array element represents one row of data (column name => column value).
+     *
+     * @phpstan-var array<string, array<string, mixed>>
+     * @psalm-var array<string, array<string, mixed>>
      */
     public $data = [];
 
@@ -85,6 +91,9 @@ abstract class BaseActiveFixture extends DbFixture implements \IteratorAggregate
      * @return array the data to be put into the database
      * @throws InvalidConfigException if the specified data file does not exist.
      * @see loadData()
+     *
+     * @phpstan-return array<string, array<string, mixed>>
+     * @psalm-return array<string, array<string, mixed>>
      */
     protected function getData()
     {