update php samples

2023-09-23 15:28:43 +08:00
parent d165b8879f
commit d58e68f8c0
27 changed files with 1860 additions and 1486 deletions
--- a/samples/client/echo_api/php-nextgen/src/Model/Bird.php
+++ b/samples/client/echo_api/php-nextgen/src/Model/Bird.php
@@ -29,8 +29,11 @@

 namespace OpenAPI\Client\Model;

-use \ArrayAccess;
-use \OpenAPI\Client\ObjectSerializer;
+use ArrayAccess;
+use JsonSerializable;
+use InvalidArgumentException;
+use ReturnTypeWillChange;
+use OpenAPI\Client\ObjectSerializer;

 /**
 * Bird Class Doc Comment
@@ -39,9 +42,9 @@ use \OpenAPI\Client\ObjectSerializer;
 * @package  OpenAPI\Client
 * @author   OpenAPI Generator team
 * @link     https://openapi-generator.tech
- * @implements \ArrayAccess<string, mixed>
+ * @implements ArrayAccess<string, mixed>
 */
-class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
+class Bird implements ModelInterface, ArrayAccess, JsonSerializable
 {
    public const DISCRIMINATOR = null;

@@ -50,14 +53,14 @@ class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
      *
      * @var string
      */
-    protected static $openAPIModelName = 'Bird';
+    protected static string $openAPIModelName = 'Bird';

    /**
      * Array of property to type mappings. Used for (de)serialization
      *
-      * @var string[]
+      * @var array<string, string>
      */
-    protected static $openAPITypes = [
+    protected static array $openAPITypes = [
        'size' => 'string',
        'color' => 'string'
    ];
@@ -65,11 +68,9 @@ class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
      * Array of property to format mappings. Used for (de)serialization
      *
-      * @var string[]
-      * @phpstan-var array<string, string|null>
-      * @psalm-var array<string, string|null>
+      * @var array<string, string|null>
      */
-    protected static $openAPIFormats = [
+    protected static array $openAPIFormats = [
        'size' => null,
        'color' => null
    ];
@@ -77,7 +78,7 @@ class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
      * Array of nullable properties. Used for (de)serialization
      *
-      * @var boolean[]
+      * @var array<string, bool>
      */
    protected static array $openAPINullables = [
        'size' => false,
@@ -87,16 +88,16 @@ class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
      * If a nullable field gets set to null, insert it here
      *
-      * @var boolean[]
+      * @var array<string, bool>
      */
    protected array $openAPINullablesSetToNull = [];

    /**
     * Array of property to type mappings. Used for (de)serialization
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function openAPITypes()
+    public static function openAPITypes(): array
    {
        return self::$openAPITypes;
    }
@@ -104,9 +105,9 @@ class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of property to format mappings. Used for (de)serialization
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function openAPIFormats()
+    public static function openAPIFormats(): array
    {
        return self::$openAPIFormats;
    }
@@ -114,7 +115,7 @@ class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of nullable properties
     *
-     * @return array
+     * @return array<string, bool>
     */
    protected static function openAPINullables(): array
    {
@@ -124,7 +125,7 @@ class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of nullable field names deliberately set to null
     *
-     * @return boolean[]
+     * @return array<string, bool>
     */
    private function getOpenAPINullablesSetToNull(): array
    {
@@ -134,7 +135,7 @@ class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Setter - Array of nullable field names deliberately set to null
     *
-     * @param boolean[] $openAPINullablesSetToNull
+     * @param array<string, bool> $openAPINullablesSetToNull
     */
    private function setOpenAPINullablesSetToNull(array $openAPINullablesSetToNull): void
    {
@@ -167,9 +168,9 @@ class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
     * Array of attributes where the key is the local name,
     * and the value is the original name
     *
-     * @var string[]
+     * @var array<string, string>
     */
-    protected static $attributeMap = [
+    protected static array $attributeMap = [
        'size' => 'size',
        'color' => 'color'
    ];
@@ -177,9 +178,9 @@ class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of attributes to setter functions (for deserialization of responses)
     *
-     * @var string[]
+     * @var array<string, string>
     */
-    protected static $setters = [
+    protected static array $setters = [
        'size' => 'setSize',
        'color' => 'setColor'
    ];
@@ -187,9 +188,9 @@ class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of attributes to getter functions (for serialization of requests)
     *
-     * @var string[]
+     * @var array<string, string>
     */
-    protected static $getters = [
+    protected static array $getters = [
        'size' => 'getSize',
        'color' => 'getColor'
    ];
@@ -198,9 +199,9 @@ class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
     * Array of attributes where the key is the local name,
     * and the value is the original name
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function attributeMap()
+    public static function attributeMap(): array
    {
        return self::$attributeMap;
    }
@@ -208,9 +209,9 @@ class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of attributes to setter functions (for deserialization of responses)
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function setters()
+    public static function setters(): array
    {
        return self::$setters;
    }
@@ -218,9 +219,9 @@ class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of attributes to getter functions (for serialization of requests)
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function getters()
+    public static function getters(): array
    {
        return self::$getters;
    }
@@ -230,7 +231,7 @@ class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string
     */
-    public function getModelName()
+    public function getModelName(): string
    {
        return self::$openAPIModelName;
    }
@@ -239,15 +240,14 @@ class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Associative array for storing property values
     *
-     * @var mixed[]
+     * @var array
     */
-    protected $container = [];
+    protected array $container = [];

    /**
     * Constructor
     *
-     * @param mixed[] $data Associated array of property values
-     *                      initializing the model
+     * @param array $data Associated array of property values initializing the model
     */
    public function __construct(array $data = null)
    {
@@ -264,7 +264,7 @@ class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
    * @param array  $fields
    * @param mixed  $defaultValue
    */
-    private function setIfExists(string $variableName, array $fields, $defaultValue): void
+    private function setIfExists(string $variableName, array $fields, mixed $defaultValue): void
    {
        if (self::isNullable($variableName) && array_key_exists($variableName, $fields) && is_null($fields[$variableName])) {
            $this->openAPINullablesSetToNull[] = $variableName;
@@ -276,9 +276,9 @@ class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Show all the invalid properties with reasons.
     *
-     * @return array invalid properties with reasons
+     * @return string[] invalid properties with reasons
     */
-    public function listInvalidProperties()
+    public function listInvalidProperties(): array
    {
        $invalidProperties = [];

@@ -291,7 +291,7 @@ class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return bool True if all properties are valid
     */
-    public function valid()
+    public function valid(): bool
    {
        return count($this->listInvalidProperties()) === 0;
    }
@@ -302,7 +302,7 @@ class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string|null
     */
-    public function getSize()
+    public function getSize(): ?string
    {
        return $this->container['size'];
    }
@@ -312,12 +312,12 @@ class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @param string|null $size size
     *
-     * @return self
+     * @return $this
     */
-    public function setSize($size)
+    public function setSize(?string $size): static
    {
        if (is_null($size)) {
-            throw new \InvalidArgumentException('non-nullable size cannot be null');
+            throw new InvalidArgumentException('non-nullable size cannot be null');
        }
        $this->container['size'] = $size;

@@ -329,7 +329,7 @@ class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string|null
     */
-    public function getColor()
+    public function getColor(): ?string
    {
        return $this->container['color'];
    }
@@ -339,12 +339,12 @@ class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @param string|null $color color
     *
-     * @return self
+     * @return $this
     */
-    public function setColor($color)
+    public function setColor(?string $color): static
    {
        if (is_null($color)) {
-            throw new \InvalidArgumentException('non-nullable color cannot be null');
+            throw new InvalidArgumentException('non-nullable color cannot be null');
        }
        $this->container['color'] = $color;

@@ -357,7 +357,7 @@ class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return boolean
     */
-    public function offsetExists($offset): bool
+    public function offsetExists(mixed $offset): bool
    {
        return isset($this->container[$offset]);
    }
@@ -369,8 +369,8 @@ class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return mixed|null
     */
-    #[\ReturnTypeWillChange]
-    public function offsetGet($offset)
+    #[ReturnTypeWillChange]
+    public function offsetGet(mixed $offset): mixed
    {
        return $this->container[$offset] ?? null;
    }
@@ -383,7 +383,7 @@ class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return void
     */
-    public function offsetSet($offset, $value): void
+    public function offsetSet(mixed $offset, mixed $value): void
    {
        if (is_null($offset)) {
            $this->container[] = $value;
@@ -399,7 +399,7 @@ class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return void
     */
-    public function offsetUnset($offset): void
+    public function offsetUnset(mixed $offset): void
    {
        unset($this->container[$offset]);
    }
@@ -411,8 +411,8 @@ class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
     * @return mixed Returns data which can be serialized by json_encode(), which is a value
     * of any type other than a resource.
     */
-    #[\ReturnTypeWillChange]
-    public function jsonSerialize()
+    #[ReturnTypeWillChange]
+    public function jsonSerialize(): mixed
    {
       return ObjectSerializer::sanitizeForSerialization($this);
    }
@@ -422,7 +422,7 @@ class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string
     */
-    public function __toString()
+    public function __toString(): string
    {
        return json_encode(
            ObjectSerializer::sanitizeForSerialization($this),
@@ -435,7 +435,7 @@ class Bird implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string
     */
-    public function toHeaderValue()
+    public function toHeaderValue(): string
    {
        return json_encode(ObjectSerializer::sanitizeForSerialization($this));
    }
--- a/samples/client/echo_api/php-nextgen/src/Model/Category.php
+++ b/samples/client/echo_api/php-nextgen/src/Model/Category.php
@@ -29,8 +29,11 @@

 namespace OpenAPI\Client\Model;

-use \ArrayAccess;
-use \OpenAPI\Client\ObjectSerializer;
+use ArrayAccess;
+use JsonSerializable;
+use InvalidArgumentException;
+use ReturnTypeWillChange;
+use OpenAPI\Client\ObjectSerializer;

 /**
 * Category Class Doc Comment
@@ -39,9 +42,9 @@ use \OpenAPI\Client\ObjectSerializer;
 * @package  OpenAPI\Client
 * @author   OpenAPI Generator team
 * @link     https://openapi-generator.tech
- * @implements \ArrayAccess<string, mixed>
+ * @implements ArrayAccess<string, mixed>
 */
-class Category implements ModelInterface, ArrayAccess, \JsonSerializable
+class Category implements ModelInterface, ArrayAccess, JsonSerializable
 {
    public const DISCRIMINATOR = null;

@@ -50,14 +53,14 @@ class Category implements ModelInterface, ArrayAccess, \JsonSerializable
      *
      * @var string
      */
-    protected static $openAPIModelName = 'Category';
+    protected static string $openAPIModelName = 'Category';

    /**
      * Array of property to type mappings. Used for (de)serialization
      *
-      * @var string[]
+      * @var array<string, string>
      */
-    protected static $openAPITypes = [
+    protected static array $openAPITypes = [
        'id' => 'int',
        'name' => 'string'
    ];
@@ -65,11 +68,9 @@ class Category implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
      * Array of property to format mappings. Used for (de)serialization
      *
-      * @var string[]
-      * @phpstan-var array<string, string|null>
-      * @psalm-var array<string, string|null>
+      * @var array<string, string|null>
      */
-    protected static $openAPIFormats = [
+    protected static array $openAPIFormats = [
        'id' => 'int64',
        'name' => null
    ];
@@ -77,7 +78,7 @@ class Category implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
      * Array of nullable properties. Used for (de)serialization
      *
-      * @var boolean[]
+      * @var array<string, bool>
      */
    protected static array $openAPINullables = [
        'id' => false,
@@ -87,16 +88,16 @@ class Category implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
      * If a nullable field gets set to null, insert it here
      *
-      * @var boolean[]
+      * @var array<string, bool>
      */
    protected array $openAPINullablesSetToNull = [];

    /**
     * Array of property to type mappings. Used for (de)serialization
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function openAPITypes()
+    public static function openAPITypes(): array
    {
        return self::$openAPITypes;
    }
@@ -104,9 +105,9 @@ class Category implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of property to format mappings. Used for (de)serialization
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function openAPIFormats()
+    public static function openAPIFormats(): array
    {
        return self::$openAPIFormats;
    }
@@ -114,7 +115,7 @@ class Category implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of nullable properties
     *
-     * @return array
+     * @return array<string, bool>
     */
    protected static function openAPINullables(): array
    {
@@ -124,7 +125,7 @@ class Category implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of nullable field names deliberately set to null
     *
-     * @return boolean[]
+     * @return array<string, bool>
     */
    private function getOpenAPINullablesSetToNull(): array
    {
@@ -134,7 +135,7 @@ class Category implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Setter - Array of nullable field names deliberately set to null
     *
-     * @param boolean[] $openAPINullablesSetToNull
+     * @param array<string, bool> $openAPINullablesSetToNull
     */
    private function setOpenAPINullablesSetToNull(array $openAPINullablesSetToNull): void
    {
@@ -167,9 +168,9 @@ class Category implements ModelInterface, ArrayAccess, \JsonSerializable
     * Array of attributes where the key is the local name,
     * and the value is the original name
     *
-     * @var string[]
+     * @var array<string, string>
     */
-    protected static $attributeMap = [
+    protected static array $attributeMap = [
        'id' => 'id',
        'name' => 'name'
    ];
@@ -177,9 +178,9 @@ class Category implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of attributes to setter functions (for deserialization of responses)
     *
-     * @var string[]
+     * @var array<string, string>
     */
-    protected static $setters = [
+    protected static array $setters = [
        'id' => 'setId',
        'name' => 'setName'
    ];
@@ -187,9 +188,9 @@ class Category implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of attributes to getter functions (for serialization of requests)
     *
-     * @var string[]
+     * @var array<string, string>
     */
-    protected static $getters = [
+    protected static array $getters = [
        'id' => 'getId',
        'name' => 'getName'
    ];
@@ -198,9 +199,9 @@ class Category implements ModelInterface, ArrayAccess, \JsonSerializable
     * Array of attributes where the key is the local name,
     * and the value is the original name
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function attributeMap()
+    public static function attributeMap(): array
    {
        return self::$attributeMap;
    }
@@ -208,9 +209,9 @@ class Category implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of attributes to setter functions (for deserialization of responses)
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function setters()
+    public static function setters(): array
    {
        return self::$setters;
    }
@@ -218,9 +219,9 @@ class Category implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of attributes to getter functions (for serialization of requests)
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function getters()
+    public static function getters(): array
    {
        return self::$getters;
    }
@@ -230,7 +231,7 @@ class Category implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string
     */
-    public function getModelName()
+    public function getModelName(): string
    {
        return self::$openAPIModelName;
    }
@@ -239,15 +240,14 @@ class Category implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Associative array for storing property values
     *
-     * @var mixed[]
+     * @var array
     */
-    protected $container = [];
+    protected array $container = [];

    /**
     * Constructor
     *
-     * @param mixed[] $data Associated array of property values
-     *                      initializing the model
+     * @param array $data Associated array of property values initializing the model
     */
    public function __construct(array $data = null)
    {
@@ -264,7 +264,7 @@ class Category implements ModelInterface, ArrayAccess, \JsonSerializable
    * @param array  $fields
    * @param mixed  $defaultValue
    */
-    private function setIfExists(string $variableName, array $fields, $defaultValue): void
+    private function setIfExists(string $variableName, array $fields, mixed $defaultValue): void
    {
        if (self::isNullable($variableName) && array_key_exists($variableName, $fields) && is_null($fields[$variableName])) {
            $this->openAPINullablesSetToNull[] = $variableName;
@@ -276,9 +276,9 @@ class Category implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Show all the invalid properties with reasons.
     *
-     * @return array invalid properties with reasons
+     * @return string[] invalid properties with reasons
     */
-    public function listInvalidProperties()
+    public function listInvalidProperties(): array
    {
        $invalidProperties = [];

@@ -291,7 +291,7 @@ class Category implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return bool True if all properties are valid
     */
-    public function valid()
+    public function valid(): bool
    {
        return count($this->listInvalidProperties()) === 0;
    }
@@ -302,7 +302,7 @@ class Category implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return int|null
     */
-    public function getId()
+    public function getId(): ?int
    {
        return $this->container['id'];
    }
@@ -312,12 +312,12 @@ class Category implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @param int|null $id id
     *
-     * @return self
+     * @return $this
     */
-    public function setId($id)
+    public function setId(?int $id): static
    {
        if (is_null($id)) {
-            throw new \InvalidArgumentException('non-nullable id cannot be null');
+            throw new InvalidArgumentException('non-nullable id cannot be null');
        }
        $this->container['id'] = $id;

@@ -329,7 +329,7 @@ class Category implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string|null
     */
-    public function getName()
+    public function getName(): ?string
    {
        return $this->container['name'];
    }
@@ -339,12 +339,12 @@ class Category implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @param string|null $name name
     *
-     * @return self
+     * @return $this
     */
-    public function setName($name)
+    public function setName(?string $name): static
    {
        if (is_null($name)) {
-            throw new \InvalidArgumentException('non-nullable name cannot be null');
+            throw new InvalidArgumentException('non-nullable name cannot be null');
        }
        $this->container['name'] = $name;

@@ -357,7 +357,7 @@ class Category implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return boolean
     */
-    public function offsetExists($offset): bool
+    public function offsetExists(mixed $offset): bool
    {
        return isset($this->container[$offset]);
    }
@@ -369,8 +369,8 @@ class Category implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return mixed|null
     */
-    #[\ReturnTypeWillChange]
-    public function offsetGet($offset)
+    #[ReturnTypeWillChange]
+    public function offsetGet(mixed $offset): mixed
    {
        return $this->container[$offset] ?? null;
    }
@@ -383,7 +383,7 @@ class Category implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return void
     */
-    public function offsetSet($offset, $value): void
+    public function offsetSet(mixed $offset, mixed $value): void
    {
        if (is_null($offset)) {
            $this->container[] = $value;
@@ -399,7 +399,7 @@ class Category implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return void
     */
-    public function offsetUnset($offset): void
+    public function offsetUnset(mixed $offset): void
    {
        unset($this->container[$offset]);
    }
@@ -411,8 +411,8 @@ class Category implements ModelInterface, ArrayAccess, \JsonSerializable
     * @return mixed Returns data which can be serialized by json_encode(), which is a value
     * of any type other than a resource.
     */
-    #[\ReturnTypeWillChange]
-    public function jsonSerialize()
+    #[ReturnTypeWillChange]
+    public function jsonSerialize(): mixed
    {
       return ObjectSerializer::sanitizeForSerialization($this);
    }
@@ -422,7 +422,7 @@ class Category implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string
     */
-    public function __toString()
+    public function __toString(): string
    {
        return json_encode(
            ObjectSerializer::sanitizeForSerialization($this),
@@ -435,7 +435,7 @@ class Category implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string
     */
-    public function toHeaderValue()
+    public function toHeaderValue(): string
    {
        return json_encode(ObjectSerializer::sanitizeForSerialization($this));
    }
--- a/samples/client/echo_api/php-nextgen/src/Model/DataQuery.php
+++ b/samples/client/echo_api/php-nextgen/src/Model/DataQuery.php
@@ -28,7 +28,6 @@
 */

 namespace OpenAPI\Client\Model;
-use \OpenAPI\Client\ObjectSerializer;

 /**
 * DataQuery Class Doc Comment
@@ -37,7 +36,7 @@ use \OpenAPI\Client\ObjectSerializer;
 * @package  OpenAPI\Client
 * @author   OpenAPI Generator team
 * @link     https://openapi-generator.tech
- * @implements \ArrayAccess<string, mixed>
+ * @implements ArrayAccess<string, mixed>
 */
 class DataQuery extends Query
 {
@@ -48,14 +47,14 @@ class DataQuery extends Query
      *
      * @var string
      */
-    protected static $openAPIModelName = 'DataQuery';
+    protected static string $openAPIModelName = 'DataQuery';

    /**
      * Array of property to type mappings. Used for (de)serialization
      *
-      * @var string[]
+      * @var array<string, string>
      */
-    protected static $openAPITypes = [
+    protected static array $openAPITypes = [
        'suffix' => 'string',
        'text' => 'string',
        'date' => '\DateTime'
@@ -64,11 +63,9 @@ class DataQuery extends Query
    /**
      * Array of property to format mappings. Used for (de)serialization
      *
-      * @var string[]
-      * @phpstan-var array<string, string|null>
-      * @psalm-var array<string, string|null>
+      * @var array<string, string|null>
      */
-    protected static $openAPIFormats = [
+    protected static array $openAPIFormats = [
        'suffix' => null,
        'text' => null,
        'date' => 'date-time'
@@ -77,7 +74,7 @@ class DataQuery extends Query
    /**
      * Array of nullable properties. Used for (de)serialization
      *
-      * @var boolean[]
+      * @var array<string, bool>
      */
    protected static array $openAPINullables = [
        'suffix' => false,
@@ -88,16 +85,16 @@ class DataQuery extends Query
    /**
      * If a nullable field gets set to null, insert it here
      *
-      * @var boolean[]
+      * @var array<string, bool>
      */
    protected array $openAPINullablesSetToNull = [];

    /**
     * Array of property to type mappings. Used for (de)serialization
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function openAPITypes()
+    public static function openAPITypes(): array
    {
        return self::$openAPITypes + parent::openAPITypes();
    }
@@ -105,9 +102,9 @@ class DataQuery extends Query
    /**
     * Array of property to format mappings. Used for (de)serialization
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function openAPIFormats()
+    public static function openAPIFormats(): array
    {
        return self::$openAPIFormats + parent::openAPIFormats();
    }
@@ -115,7 +112,7 @@ class DataQuery extends Query
    /**
     * Array of nullable properties
     *
-     * @return array
+     * @return array<string, bool>
     */
    protected static function openAPINullables(): array
    {
@@ -125,7 +122,7 @@ class DataQuery extends Query
    /**
     * Array of nullable field names deliberately set to null
     *
-     * @return boolean[]
+     * @return array<string, bool>
     */
    private function getOpenAPINullablesSetToNull(): array
    {
@@ -135,7 +132,7 @@ class DataQuery extends Query
    /**
     * Setter - Array of nullable field names deliberately set to null
     *
-     * @param boolean[] $openAPINullablesSetToNull
+     * @param array<string, bool> $openAPINullablesSetToNull
     */
    private function setOpenAPINullablesSetToNull(array $openAPINullablesSetToNull): void
    {
@@ -168,9 +165,9 @@ class DataQuery extends Query
     * Array of attributes where the key is the local name,
     * and the value is the original name
     *
-     * @var string[]
+     * @var array<string, string>
     */
-    protected static $attributeMap = [
+    protected static array $attributeMap = [
        'suffix' => 'suffix',
        'text' => 'text',
        'date' => 'date'
@@ -179,9 +176,9 @@ class DataQuery extends Query
    /**
     * Array of attributes to setter functions (for deserialization of responses)
     *
-     * @var string[]
+     * @var array<string, string>
     */
-    protected static $setters = [
+    protected static array $setters = [
        'suffix' => 'setSuffix',
        'text' => 'setText',
        'date' => 'setDate'
@@ -190,9 +187,9 @@ class DataQuery extends Query
    /**
     * Array of attributes to getter functions (for serialization of requests)
     *
-     * @var string[]
+     * @var array<string, string>
     */
-    protected static $getters = [
+    protected static array $getters = [
        'suffix' => 'getSuffix',
        'text' => 'getText',
        'date' => 'getDate'
@@ -202,9 +199,9 @@ class DataQuery extends Query
     * Array of attributes where the key is the local name,
     * and the value is the original name
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function attributeMap()
+    public static function attributeMap(): array
    {
        return parent::attributeMap() + self::$attributeMap;
    }
@@ -212,9 +209,9 @@ class DataQuery extends Query
    /**
     * Array of attributes to setter functions (for deserialization of responses)
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function setters()
+    public static function setters(): array
    {
        return parent::setters() + self::$setters;
    }
@@ -222,9 +219,9 @@ class DataQuery extends Query
    /**
     * Array of attributes to getter functions (for serialization of requests)
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function getters()
+    public static function getters(): array
    {
        return parent::getters() + self::$getters;
    }
@@ -234,7 +231,7 @@ class DataQuery extends Query
     *
     * @return string
     */
-    public function getModelName()
+    public function getModelName(): string
    {
        return self::$openAPIModelName;
    }
@@ -244,8 +241,7 @@ class DataQuery extends Query
    /**
     * Constructor
     *
-     * @param mixed[] $data Associated array of property values
-     *                      initializing the model
+     * @param array $data Associated array of property values initializing the model
     */
    public function __construct(array $data = null)
    {
@@ -265,7 +261,7 @@ class DataQuery extends Query
    * @param array  $fields
    * @param mixed  $defaultValue
    */
-    private function setIfExists(string $variableName, array $fields, $defaultValue): void
+    private function setIfExists(string $variableName, array $fields, mixed $defaultValue): void
    {
        if (self::isNullable($variableName) && array_key_exists($variableName, $fields) && is_null($fields[$variableName])) {
            $this->openAPINullablesSetToNull[] = $variableName;
@@ -277,9 +273,9 @@ class DataQuery extends Query
    /**
     * Show all the invalid properties with reasons.
     *
-     * @return array invalid properties with reasons
+     * @return string[] invalid properties with reasons
     */
-    public function listInvalidProperties()
+    public function listInvalidProperties(): array
    {
        $invalidProperties = parent::listInvalidProperties();

@@ -292,7 +288,7 @@ class DataQuery extends Query
     *
     * @return bool True if all properties are valid
     */
-    public function valid()
+    public function valid(): bool
    {
        return count($this->listInvalidProperties()) === 0;
    }
@@ -303,7 +299,7 @@ class DataQuery extends Query
     *
     * @return string|null
     */
-    public function getSuffix()
+    public function getSuffix(): ?string
    {
        return $this->container['suffix'];
    }
@@ -313,12 +309,12 @@ class DataQuery extends Query
     *
     * @param string|null $suffix test suffix
     *
-     * @return self
+     * @return $this
     */
-    public function setSuffix($suffix)
+    public function setSuffix(?string $suffix): static
    {
        if (is_null($suffix)) {
-            throw new \InvalidArgumentException('non-nullable suffix cannot be null');
+            throw new InvalidArgumentException('non-nullable suffix cannot be null');
        }
        $this->container['suffix'] = $suffix;

@@ -330,7 +326,7 @@ class DataQuery extends Query
     *
     * @return string|null
     */
-    public function getText()
+    public function getText(): ?string
    {
        return $this->container['text'];
    }
@@ -340,12 +336,12 @@ class DataQuery extends Query
     *
     * @param string|null $text Some text containing white spaces
     *
-     * @return self
+     * @return $this
     */
-    public function setText($text)
+    public function setText(?string $text): static
    {
        if (is_null($text)) {
-            throw new \InvalidArgumentException('non-nullable text cannot be null');
+            throw new InvalidArgumentException('non-nullable text cannot be null');
        }
        $this->container['text'] = $text;

@@ -357,7 +353,7 @@ class DataQuery extends Query
     *
     * @return \DateTime|null
     */
-    public function getDate()
+    public function getDate(): ?\DateTime
    {
        return $this->container['date'];
    }
@@ -367,12 +363,12 @@ class DataQuery extends Query
     *
     * @param \DateTime|null $date A date
     *
-     * @return self
+     * @return $this
     */
-    public function setDate($date)
+    public function setDate(?\DateTime $date): static
    {
        if (is_null($date)) {
-            throw new \InvalidArgumentException('non-nullable date cannot be null');
+            throw new InvalidArgumentException('non-nullable date cannot be null');
        }
        $this->container['date'] = $date;

@@ -385,7 +381,7 @@ class DataQuery extends Query
     *
     * @return boolean
     */
-    public function offsetExists($offset): bool
+    public function offsetExists(mixed $offset): bool
    {
        return isset($this->container[$offset]);
    }
@@ -397,8 +393,8 @@ class DataQuery extends Query
     *
     * @return mixed|null
     */
-    #[\ReturnTypeWillChange]
-    public function offsetGet($offset)
+    #[ReturnTypeWillChange]
+    public function offsetGet(mixed $offset): mixed
    {
        return $this->container[$offset] ?? null;
    }
@@ -411,7 +407,7 @@ class DataQuery extends Query
     *
     * @return void
     */
-    public function offsetSet($offset, $value): void
+    public function offsetSet(mixed $offset, mixed $value): void
    {
        if (is_null($offset)) {
            $this->container[] = $value;
@@ -427,7 +423,7 @@ class DataQuery extends Query
     *
     * @return void
     */
-    public function offsetUnset($offset): void
+    public function offsetUnset(mixed $offset): void
    {
        unset($this->container[$offset]);
    }
@@ -439,8 +435,8 @@ class DataQuery extends Query
     * @return mixed Returns data which can be serialized by json_encode(), which is a value
     * of any type other than a resource.
     */
-    #[\ReturnTypeWillChange]
-    public function jsonSerialize()
+    #[ReturnTypeWillChange]
+    public function jsonSerialize(): mixed
    {
       return ObjectSerializer::sanitizeForSerialization($this);
    }
@@ -450,7 +446,7 @@ class DataQuery extends Query
     *
     * @return string
     */
-    public function __toString()
+    public function __toString(): string
    {
        return json_encode(
            ObjectSerializer::sanitizeForSerialization($this),
@@ -463,7 +459,7 @@ class DataQuery extends Query
     *
     * @return string
     */
-    public function toHeaderValue()
+    public function toHeaderValue(): string
    {
        return json_encode(ObjectSerializer::sanitizeForSerialization($this));
    }
--- a/samples/client/echo_api/php-nextgen/src/Model/DefaultValue.php
+++ b/samples/client/echo_api/php-nextgen/src/Model/DefaultValue.php
@@ -29,8 +29,11 @@

 namespace OpenAPI\Client\Model;

-use \ArrayAccess;
-use \OpenAPI\Client\ObjectSerializer;
+use ArrayAccess;
+use JsonSerializable;
+use InvalidArgumentException;
+use ReturnTypeWillChange;
+use OpenAPI\Client\ObjectSerializer;

 /**
 * DefaultValue Class Doc Comment
@@ -40,9 +43,9 @@ use \OpenAPI\Client\ObjectSerializer;
 * @package  OpenAPI\Client
 * @author   OpenAPI Generator team
 * @link     https://openapi-generator.tech
- * @implements \ArrayAccess<string, mixed>
+ * @implements ArrayAccess<string, mixed>
 */
-class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
+class DefaultValue implements ModelInterface, ArrayAccess, JsonSerializable
 {
    public const DISCRIMINATOR = null;

@@ -51,14 +54,14 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
      *
      * @var string
      */
-    protected static $openAPIModelName = 'DefaultValue';
+    protected static string $openAPIModelName = 'DefaultValue';

    /**
      * Array of property to type mappings. Used for (de)serialization
      *
-      * @var string[]
+      * @var array<string, string>
      */
-    protected static $openAPITypes = [
+    protected static array $openAPITypes = [
        'array_string_enum_ref_default' => '\OpenAPI\Client\Model\StringEnumRef[]',
        'array_string_enum_default' => 'string[]',
        'array_string_default' => 'string[]',
@@ -72,11 +75,9 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
      * Array of property to format mappings. Used for (de)serialization
      *
-      * @var string[]
-      * @phpstan-var array<string, string|null>
-      * @psalm-var array<string, string|null>
+      * @var array<string, string|null>
      */
-    protected static $openAPIFormats = [
+    protected static array $openAPIFormats = [
        'array_string_enum_ref_default' => null,
        'array_string_enum_default' => null,
        'array_string_default' => null,
@@ -90,7 +91,7 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
      * Array of nullable properties. Used for (de)serialization
      *
-      * @var boolean[]
+      * @var array<string, bool>
      */
    protected static array $openAPINullables = [
        'array_string_enum_ref_default' => false,
@@ -106,16 +107,16 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
      * If a nullable field gets set to null, insert it here
      *
-      * @var boolean[]
+      * @var array<string, bool>
      */
    protected array $openAPINullablesSetToNull = [];

    /**
     * Array of property to type mappings. Used for (de)serialization
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function openAPITypes()
+    public static function openAPITypes(): array
    {
        return self::$openAPITypes;
    }
@@ -123,9 +124,9 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of property to format mappings. Used for (de)serialization
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function openAPIFormats()
+    public static function openAPIFormats(): array
    {
        return self::$openAPIFormats;
    }
@@ -133,7 +134,7 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of nullable properties
     *
-     * @return array
+     * @return array<string, bool>
     */
    protected static function openAPINullables(): array
    {
@@ -143,7 +144,7 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of nullable field names deliberately set to null
     *
-     * @return boolean[]
+     * @return array<string, bool>
     */
    private function getOpenAPINullablesSetToNull(): array
    {
@@ -153,7 +154,7 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Setter - Array of nullable field names deliberately set to null
     *
-     * @param boolean[] $openAPINullablesSetToNull
+     * @param array<string, bool> $openAPINullablesSetToNull
     */
    private function setOpenAPINullablesSetToNull(array $openAPINullablesSetToNull): void
    {
@@ -186,9 +187,9 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
     * Array of attributes where the key is the local name,
     * and the value is the original name
     *
-     * @var string[]
+     * @var array<string, string>
     */
-    protected static $attributeMap = [
+    protected static array $attributeMap = [
        'array_string_enum_ref_default' => 'array_string_enum_ref_default',
        'array_string_enum_default' => 'array_string_enum_default',
        'array_string_default' => 'array_string_default',
@@ -202,9 +203,9 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of attributes to setter functions (for deserialization of responses)
     *
-     * @var string[]
+     * @var array<string, string>
     */
-    protected static $setters = [
+    protected static array $setters = [
        'array_string_enum_ref_default' => 'setArrayStringEnumRefDefault',
        'array_string_enum_default' => 'setArrayStringEnumDefault',
        'array_string_default' => 'setArrayStringDefault',
@@ -218,9 +219,9 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of attributes to getter functions (for serialization of requests)
     *
-     * @var string[]
+     * @var array<string, string>
     */
-    protected static $getters = [
+    protected static array $getters = [
        'array_string_enum_ref_default' => 'getArrayStringEnumRefDefault',
        'array_string_enum_default' => 'getArrayStringEnumDefault',
        'array_string_default' => 'getArrayStringDefault',
@@ -235,9 +236,9 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
     * Array of attributes where the key is the local name,
     * and the value is the original name
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function attributeMap()
+    public static function attributeMap(): array
    {
        return self::$attributeMap;
    }
@@ -245,9 +246,9 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of attributes to setter functions (for deserialization of responses)
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function setters()
+    public static function setters(): array
    {
        return self::$setters;
    }
@@ -255,9 +256,9 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of attributes to getter functions (for serialization of requests)
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function getters()
+    public static function getters(): array
    {
        return self::$getters;
    }
@@ -267,7 +268,7 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string
     */
-    public function getModelName()
+    public function getModelName(): string
    {
        return self::$openAPIModelName;
    }
@@ -293,22 +294,21 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Associative array for storing property values
     *
-     * @var mixed[]
+     * @var array
     */
-    protected $container = [];
+    protected array $container = [];

    /**
     * Constructor
     *
-     * @param mixed[] $data Associated array of property values
-     *                      initializing the model
+     * @param array $data Associated array of property values initializing the model
     */
    public function __construct(array $data = null)
    {
-        $this->setIfExists('array_string_enum_ref_default', $data ?? [], null);
-        $this->setIfExists('array_string_enum_default', $data ?? [], null);
-        $this->setIfExists('array_string_default', $data ?? [], null);
-        $this->setIfExists('array_integer_default', $data ?? [], null);
+        $this->setIfExists('array_string_enum_ref_default', $data ?? [], [["success","failure"]]);
+        $this->setIfExists('array_string_enum_default', $data ?? [], [["success","failure"]]);
+        $this->setIfExists('array_string_default', $data ?? [], [["failure","skipped"]]);
+        $this->setIfExists('array_integer_default', $data ?? [], [[1,3]]);
        $this->setIfExists('array_string', $data ?? [], null);
        $this->setIfExists('array_string_nullable', $data ?? [], null);
        $this->setIfExists('array_string_extension_nullable', $data ?? [], null);
@@ -324,7 +324,7 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
    * @param array  $fields
    * @param mixed  $defaultValue
    */
-    private function setIfExists(string $variableName, array $fields, $defaultValue): void
+    private function setIfExists(string $variableName, array $fields, mixed $defaultValue): void
    {
        if (self::isNullable($variableName) && array_key_exists($variableName, $fields) && is_null($fields[$variableName])) {
            $this->openAPINullablesSetToNull[] = $variableName;
@@ -336,9 +336,9 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Show all the invalid properties with reasons.
     *
-     * @return array invalid properties with reasons
+     * @return string[] invalid properties with reasons
     */
-    public function listInvalidProperties()
+    public function listInvalidProperties(): array
    {
        $invalidProperties = [];

@@ -351,7 +351,7 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return bool True if all properties are valid
     */
-    public function valid()
+    public function valid(): bool
    {
        return count($this->listInvalidProperties()) === 0;
    }
@@ -362,7 +362,7 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return \OpenAPI\Client\Model\StringEnumRef[]|null
     */
-    public function getArrayStringEnumRefDefault()
+    public function getArrayStringEnumRefDefault(): ?array
    {
        return $this->container['array_string_enum_ref_default'];
    }
@@ -372,12 +372,12 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @param \OpenAPI\Client\Model\StringEnumRef[]|null $array_string_enum_ref_default array_string_enum_ref_default
     *
-     * @return self
+     * @return $this
     */
-    public function setArrayStringEnumRefDefault($array_string_enum_ref_default)
+    public function setArrayStringEnumRefDefault(?array $array_string_enum_ref_default): static
    {
        if (is_null($array_string_enum_ref_default)) {
-            throw new \InvalidArgumentException('non-nullable array_string_enum_ref_default cannot be null');
+            throw new InvalidArgumentException('non-nullable array_string_enum_ref_default cannot be null');
        }
        $this->container['array_string_enum_ref_default'] = $array_string_enum_ref_default;

@@ -389,7 +389,7 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string[]|null
     */
-    public function getArrayStringEnumDefault()
+    public function getArrayStringEnumDefault(): ?array
    {
        return $this->container['array_string_enum_default'];
    }
@@ -399,16 +399,16 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @param string[]|null $array_string_enum_default array_string_enum_default
     *
-     * @return self
+     * @return $this
     */
-    public function setArrayStringEnumDefault($array_string_enum_default)
+    public function setArrayStringEnumDefault(?array $array_string_enum_default): static
    {
        if (is_null($array_string_enum_default)) {
-            throw new \InvalidArgumentException('non-nullable array_string_enum_default cannot be null');
+            throw new InvalidArgumentException('non-nullable array_string_enum_default cannot be null');
        }
        $allowedValues = $this->getArrayStringEnumDefaultAllowableValues();
        if (array_diff($array_string_enum_default, $allowedValues)) {
-            throw new \InvalidArgumentException(
+            throw new InvalidArgumentException(
                sprintf(
                    "Invalid value for 'array_string_enum_default', must be one of '%s'",
                    implode("', '", $allowedValues)
@@ -425,7 +425,7 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string[]|null
     */
-    public function getArrayStringDefault()
+    public function getArrayStringDefault(): ?array
    {
        return $this->container['array_string_default'];
    }
@@ -435,12 +435,12 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @param string[]|null $array_string_default array_string_default
     *
-     * @return self
+     * @return $this
     */
-    public function setArrayStringDefault($array_string_default)
+    public function setArrayStringDefault(?array $array_string_default): static
    {
        if (is_null($array_string_default)) {
-            throw new \InvalidArgumentException('non-nullable array_string_default cannot be null');
+            throw new InvalidArgumentException('non-nullable array_string_default cannot be null');
        }
        $this->container['array_string_default'] = $array_string_default;

@@ -452,7 +452,7 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return int[]|null
     */
-    public function getArrayIntegerDefault()
+    public function getArrayIntegerDefault(): ?array
    {
        return $this->container['array_integer_default'];
    }
@@ -462,12 +462,12 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @param int[]|null $array_integer_default array_integer_default
     *
-     * @return self
+     * @return $this
     */
-    public function setArrayIntegerDefault($array_integer_default)
+    public function setArrayIntegerDefault(?array $array_integer_default): static
    {
        if (is_null($array_integer_default)) {
-            throw new \InvalidArgumentException('non-nullable array_integer_default cannot be null');
+            throw new InvalidArgumentException('non-nullable array_integer_default cannot be null');
        }
        $this->container['array_integer_default'] = $array_integer_default;

@@ -479,7 +479,7 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string[]|null
     */
-    public function getArrayString()
+    public function getArrayString(): ?array
    {
        return $this->container['array_string'];
    }
@@ -489,12 +489,12 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @param string[]|null $array_string array_string
     *
-     * @return self
+     * @return $this
     */
-    public function setArrayString($array_string)
+    public function setArrayString(?array $array_string): static
    {
        if (is_null($array_string)) {
-            throw new \InvalidArgumentException('non-nullable array_string cannot be null');
+            throw new InvalidArgumentException('non-nullable array_string cannot be null');
        }
        $this->container['array_string'] = $array_string;

@@ -506,7 +506,7 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string[]|null
     */
-    public function getArrayStringNullable()
+    public function getArrayStringNullable(): ?array
    {
        return $this->container['array_string_nullable'];
    }
@@ -516,9 +516,9 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @param string[]|null $array_string_nullable array_string_nullable
     *
-     * @return self
+     * @return $this
     */
-    public function setArrayStringNullable($array_string_nullable)
+    public function setArrayStringNullable(?array $array_string_nullable): static
    {
        if (is_null($array_string_nullable)) {
            array_push($this->openAPINullablesSetToNull, 'array_string_nullable');
@@ -540,7 +540,7 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string[]|null
     */
-    public function getArrayStringExtensionNullable()
+    public function getArrayStringExtensionNullable(): ?array
    {
        return $this->container['array_string_extension_nullable'];
    }
@@ -550,9 +550,9 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @param string[]|null $array_string_extension_nullable array_string_extension_nullable
     *
-     * @return self
+     * @return $this
     */
-    public function setArrayStringExtensionNullable($array_string_extension_nullable)
+    public function setArrayStringExtensionNullable(?array $array_string_extension_nullable): static
    {
        if (is_null($array_string_extension_nullable)) {
            array_push($this->openAPINullablesSetToNull, 'array_string_extension_nullable');
@@ -574,7 +574,7 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string|null
     */
-    public function getStringNullable()
+    public function getStringNullable(): ?string
    {
        return $this->container['string_nullable'];
    }
@@ -584,9 +584,9 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @param string|null $string_nullable string_nullable
     *
-     * @return self
+     * @return $this
     */
-    public function setStringNullable($string_nullable)
+    public function setStringNullable(?string $string_nullable): static
    {
        if (is_null($string_nullable)) {
            array_push($this->openAPINullablesSetToNull, 'string_nullable');
@@ -609,7 +609,7 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return boolean
     */
-    public function offsetExists($offset): bool
+    public function offsetExists(mixed $offset): bool
    {
        return isset($this->container[$offset]);
    }
@@ -621,8 +621,8 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return mixed|null
     */
-    #[\ReturnTypeWillChange]
-    public function offsetGet($offset)
+    #[ReturnTypeWillChange]
+    public function offsetGet(mixed $offset): mixed
    {
        return $this->container[$offset] ?? null;
    }
@@ -635,7 +635,7 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return void
     */
-    public function offsetSet($offset, $value): void
+    public function offsetSet(mixed $offset, mixed $value): void
    {
        if (is_null($offset)) {
            $this->container[] = $value;
@@ -651,7 +651,7 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return void
     */
-    public function offsetUnset($offset): void
+    public function offsetUnset(mixed $offset): void
    {
        unset($this->container[$offset]);
    }
@@ -663,8 +663,8 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
     * @return mixed Returns data which can be serialized by json_encode(), which is a value
     * of any type other than a resource.
     */
-    #[\ReturnTypeWillChange]
-    public function jsonSerialize()
+    #[ReturnTypeWillChange]
+    public function jsonSerialize(): mixed
    {
       return ObjectSerializer::sanitizeForSerialization($this);
    }
@@ -674,7 +674,7 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string
     */
-    public function __toString()
+    public function __toString(): string
    {
        return json_encode(
            ObjectSerializer::sanitizeForSerialization($this),
@@ -687,7 +687,7 @@ class DefaultValue implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string
     */
-    public function toHeaderValue()
+    public function toHeaderValue(): string
    {
        return json_encode(ObjectSerializer::sanitizeForSerialization($this));
    }
--- a/samples/client/echo_api/php-nextgen/src/Model/ModelInterface.php
+++ b/samples/client/echo_api/php-nextgen/src/Model/ModelInterface.php
@@ -42,49 +42,49 @@ interface ModelInterface
     *
     * @return string
     */
-    public function getModelName();
+    public function getModelName(): string;

    /**
     * Array of property to type mappings. Used for (de)serialization
     *
     * @return array
     */
-    public static function openAPITypes();
+    public static function openAPITypes(): array;

    /**
     * Array of property to format mappings. Used for (de)serialization
     *
     * @return array
     */
-    public static function openAPIFormats();
+    public static function openAPIFormats(): array;

    /**
     * Array of attributes where the key is the local name, and the value is the original name
     *
     * @return array
     */
-    public static function attributeMap();
+    public static function attributeMap(): array;

    /**
     * Array of attributes to setter functions (for deserialization of responses)
     *
     * @return array
     */
-    public static function setters();
+    public static function setters(): array;

    /**
     * Array of attributes to getter functions (for serialization of requests)
     *
     * @return array
     */
-    public static function getters();
+    public static function getters(): array;

    /**
     * Show all the invalid properties with reasons.
     *
     * @return array
     */
-    public function listInvalidProperties();
+    public function listInvalidProperties(): array;

    /**
     * Validate all the properties in the model
@@ -92,7 +92,7 @@ interface ModelInterface
     *
     * @return bool
     */
-    public function valid();
+    public function valid(): bool;

    /**
     * Checks if a property is nullable
--- a/samples/client/echo_api/php-nextgen/src/Model/NumberPropertiesOnly.php
+++ b/samples/client/echo_api/php-nextgen/src/Model/NumberPropertiesOnly.php
@@ -29,8 +29,11 @@

 namespace OpenAPI\Client\Model;

-use \ArrayAccess;
-use \OpenAPI\Client\ObjectSerializer;
+use ArrayAccess;
+use JsonSerializable;
+use InvalidArgumentException;
+use ReturnTypeWillChange;
+use OpenAPI\Client\ObjectSerializer;

 /**
 * NumberPropertiesOnly Class Doc Comment
@@ -39,9 +42,9 @@ use \OpenAPI\Client\ObjectSerializer;
 * @package  OpenAPI\Client
 * @author   OpenAPI Generator team
 * @link     https://openapi-generator.tech
- * @implements \ArrayAccess<string, mixed>
+ * @implements ArrayAccess<string, mixed>
 */
-class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializable
+class NumberPropertiesOnly implements ModelInterface, ArrayAccess, JsonSerializable
 {
    public const DISCRIMINATOR = null;

@@ -50,14 +53,14 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
      *
      * @var string
      */
-    protected static $openAPIModelName = 'NumberPropertiesOnly';
+    protected static string $openAPIModelName = 'NumberPropertiesOnly';

    /**
      * Array of property to type mappings. Used for (de)serialization
      *
-      * @var string[]
+      * @var array<string, string>
      */
-    protected static $openAPITypes = [
+    protected static array $openAPITypes = [
        'number' => 'float',
        'float' => 'float',
        'double' => 'float'
@@ -66,11 +69,9 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
    /**
      * Array of property to format mappings. Used for (de)serialization
      *
-      * @var string[]
-      * @phpstan-var array<string, string|null>
-      * @psalm-var array<string, string|null>
+      * @var array<string, string|null>
      */
-    protected static $openAPIFormats = [
+    protected static array $openAPIFormats = [
        'number' => null,
        'float' => 'float',
        'double' => 'double'
@@ -79,7 +80,7 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
    /**
      * Array of nullable properties. Used for (de)serialization
      *
-      * @var boolean[]
+      * @var array<string, bool>
      */
    protected static array $openAPINullables = [
        'number' => false,
@@ -90,16 +91,16 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
    /**
      * If a nullable field gets set to null, insert it here
      *
-      * @var boolean[]
+      * @var array<string, bool>
      */
    protected array $openAPINullablesSetToNull = [];

    /**
     * Array of property to type mappings. Used for (de)serialization
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function openAPITypes()
+    public static function openAPITypes(): array
    {
        return self::$openAPITypes;
    }
@@ -107,9 +108,9 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
    /**
     * Array of property to format mappings. Used for (de)serialization
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function openAPIFormats()
+    public static function openAPIFormats(): array
    {
        return self::$openAPIFormats;
    }
@@ -117,7 +118,7 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
    /**
     * Array of nullable properties
     *
-     * @return array
+     * @return array<string, bool>
     */
    protected static function openAPINullables(): array
    {
@@ -127,7 +128,7 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
    /**
     * Array of nullable field names deliberately set to null
     *
-     * @return boolean[]
+     * @return array<string, bool>
     */
    private function getOpenAPINullablesSetToNull(): array
    {
@@ -137,7 +138,7 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
    /**
     * Setter - Array of nullable field names deliberately set to null
     *
-     * @param boolean[] $openAPINullablesSetToNull
+     * @param array<string, bool> $openAPINullablesSetToNull
     */
    private function setOpenAPINullablesSetToNull(array $openAPINullablesSetToNull): void
    {
@@ -170,9 +171,9 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
     * Array of attributes where the key is the local name,
     * and the value is the original name
     *
-     * @var string[]
+     * @var array<string, string>
     */
-    protected static $attributeMap = [
+    protected static array $attributeMap = [
        'number' => 'number',
        'float' => 'float',
        'double' => 'double'
@@ -181,9 +182,9 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
    /**
     * Array of attributes to setter functions (for deserialization of responses)
     *
-     * @var string[]
+     * @var array<string, string>
     */
-    protected static $setters = [
+    protected static array $setters = [
        'number' => 'setNumber',
        'float' => 'setFloat',
        'double' => 'setDouble'
@@ -192,9 +193,9 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
    /**
     * Array of attributes to getter functions (for serialization of requests)
     *
-     * @var string[]
+     * @var array<string, string>
     */
-    protected static $getters = [
+    protected static array $getters = [
        'number' => 'getNumber',
        'float' => 'getFloat',
        'double' => 'getDouble'
@@ -204,9 +205,9 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
     * Array of attributes where the key is the local name,
     * and the value is the original name
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function attributeMap()
+    public static function attributeMap(): array
    {
        return self::$attributeMap;
    }
@@ -214,9 +215,9 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
    /**
     * Array of attributes to setter functions (for deserialization of responses)
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function setters()
+    public static function setters(): array
    {
        return self::$setters;
    }
@@ -224,9 +225,9 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
    /**
     * Array of attributes to getter functions (for serialization of requests)
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function getters()
+    public static function getters(): array
    {
        return self::$getters;
    }
@@ -236,7 +237,7 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
     *
     * @return string
     */
-    public function getModelName()
+    public function getModelName(): string
    {
        return self::$openAPIModelName;
    }
@@ -245,15 +246,14 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
    /**
     * Associative array for storing property values
     *
-     * @var mixed[]
+     * @var array
     */
-    protected $container = [];
+    protected array $container = [];

    /**
     * Constructor
     *
-     * @param mixed[] $data Associated array of property values
-     *                      initializing the model
+     * @param array $data Associated array of property values initializing the model
     */
    public function __construct(array $data = null)
    {
@@ -271,7 +271,7 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
    * @param array  $fields
    * @param mixed  $defaultValue
    */
-    private function setIfExists(string $variableName, array $fields, $defaultValue): void
+    private function setIfExists(string $variableName, array $fields, mixed $defaultValue): void
    {
        if (self::isNullable($variableName) && array_key_exists($variableName, $fields) && is_null($fields[$variableName])) {
            $this->openAPINullablesSetToNull[] = $variableName;
@@ -283,9 +283,9 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
    /**
     * Show all the invalid properties with reasons.
     *
-     * @return array invalid properties with reasons
+     * @return string[] invalid properties with reasons
     */
-    public function listInvalidProperties()
+    public function listInvalidProperties(): array
    {
        $invalidProperties = [];

@@ -306,7 +306,7 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
     *
     * @return bool True if all properties are valid
     */
-    public function valid()
+    public function valid(): bool
    {
        return count($this->listInvalidProperties()) === 0;
    }
@@ -317,7 +317,7 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
     *
     * @return float|null
     */
-    public function getNumber()
+    public function getNumber(): ?float
    {
        return $this->container['number'];
    }
@@ -327,12 +327,12 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
     *
     * @param float|null $number number
     *
-     * @return self
+     * @return $this
     */
-    public function setNumber($number)
+    public function setNumber(?float $number): static
    {
        if (is_null($number)) {
-            throw new \InvalidArgumentException('non-nullable number cannot be null');
+            throw new InvalidArgumentException('non-nullable number cannot be null');
        }
        $this->container['number'] = $number;

@@ -344,7 +344,7 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
     *
     * @return float|null
     */
-    public function getFloat()
+    public function getFloat(): ?float
    {
        return $this->container['float'];
    }
@@ -354,12 +354,12 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
     *
     * @param float|null $float float
     *
-     * @return self
+     * @return $this
     */
-    public function setFloat($float)
+    public function setFloat(?float $float): static
    {
        if (is_null($float)) {
-            throw new \InvalidArgumentException('non-nullable float cannot be null');
+            throw new InvalidArgumentException('non-nullable float cannot be null');
        }
        $this->container['float'] = $float;

@@ -371,7 +371,7 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
     *
     * @return float|null
     */
-    public function getDouble()
+    public function getDouble(): ?float
    {
        return $this->container['double'];
    }
@@ -381,19 +381,19 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
     *
     * @param float|null $double double
     *
-     * @return self
+     * @return $this
     */
-    public function setDouble($double)
+    public function setDouble(?float $double): static
    {
        if (is_null($double)) {
-            throw new \InvalidArgumentException('non-nullable double cannot be null');
+            throw new InvalidArgumentException('non-nullable double cannot be null');
        }

        if (($double > 50.2)) {
-            throw new \InvalidArgumentException('invalid value for $double when calling NumberPropertiesOnly., must be smaller than or equal to 50.2.');
+            throw new InvalidArgumentException('invalid value for $double when calling NumberPropertiesOnly., must be smaller than or equal to 50.2.');
        }
        if (($double < 0.8)) {
-            throw new \InvalidArgumentException('invalid value for $double when calling NumberPropertiesOnly., must be bigger than or equal to 0.8.');
+            throw new InvalidArgumentException('invalid value for $double when calling NumberPropertiesOnly., must be bigger than or equal to 0.8.');
        }

        $this->container['double'] = $double;
@@ -407,7 +407,7 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
     *
     * @return boolean
     */
-    public function offsetExists($offset): bool
+    public function offsetExists(mixed $offset): bool
    {
        return isset($this->container[$offset]);
    }
@@ -419,8 +419,8 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
     *
     * @return mixed|null
     */
-    #[\ReturnTypeWillChange]
-    public function offsetGet($offset)
+    #[ReturnTypeWillChange]
+    public function offsetGet(mixed $offset): mixed
    {
        return $this->container[$offset] ?? null;
    }
@@ -433,7 +433,7 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
     *
     * @return void
     */
-    public function offsetSet($offset, $value): void
+    public function offsetSet(mixed $offset, mixed $value): void
    {
        if (is_null($offset)) {
            $this->container[] = $value;
@@ -449,7 +449,7 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
     *
     * @return void
     */
-    public function offsetUnset($offset): void
+    public function offsetUnset(mixed $offset): void
    {
        unset($this->container[$offset]);
    }
@@ -461,8 +461,8 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
     * @return mixed Returns data which can be serialized by json_encode(), which is a value
     * of any type other than a resource.
     */
-    #[\ReturnTypeWillChange]
-    public function jsonSerialize()
+    #[ReturnTypeWillChange]
+    public function jsonSerialize(): mixed
    {
       return ObjectSerializer::sanitizeForSerialization($this);
    }
@@ -472,7 +472,7 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
     *
     * @return string
     */
-    public function __toString()
+    public function __toString(): string
    {
        return json_encode(
            ObjectSerializer::sanitizeForSerialization($this),
@@ -485,7 +485,7 @@ class NumberPropertiesOnly implements ModelInterface, ArrayAccess, \JsonSerializ
     *
     * @return string
     */
-    public function toHeaderValue()
+    public function toHeaderValue(): string
    {
        return json_encode(ObjectSerializer::sanitizeForSerialization($this));
    }
--- a/samples/client/echo_api/php-nextgen/src/Model/Pet.php
+++ b/samples/client/echo_api/php-nextgen/src/Model/Pet.php
@@ -29,8 +29,11 @@

 namespace OpenAPI\Client\Model;

-use \ArrayAccess;
-use \OpenAPI\Client\ObjectSerializer;
+use ArrayAccess;
+use JsonSerializable;
+use InvalidArgumentException;
+use ReturnTypeWillChange;
+use OpenAPI\Client\ObjectSerializer;

 /**
 * Pet Class Doc Comment
@@ -39,9 +42,9 @@ use \OpenAPI\Client\ObjectSerializer;
 * @package  OpenAPI\Client
 * @author   OpenAPI Generator team
 * @link     https://openapi-generator.tech
- * @implements \ArrayAccess<string, mixed>
+ * @implements ArrayAccess<string, mixed>
 */
-class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
+class Pet implements ModelInterface, ArrayAccess, JsonSerializable
 {
    public const DISCRIMINATOR = null;

@@ -50,14 +53,14 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
      *
      * @var string
      */
-    protected static $openAPIModelName = 'Pet';
+    protected static string $openAPIModelName = 'Pet';

    /**
      * Array of property to type mappings. Used for (de)serialization
      *
-      * @var string[]
+      * @var array<string, string>
      */
-    protected static $openAPITypes = [
+    protected static array $openAPITypes = [
        'id' => 'int',
        'name' => 'string',
        'category' => '\OpenAPI\Client\Model\Category',
@@ -69,11 +72,9 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
      * Array of property to format mappings. Used for (de)serialization
      *
-      * @var string[]
-      * @phpstan-var array<string, string|null>
-      * @psalm-var array<string, string|null>
+      * @var array<string, string|null>
      */
-    protected static $openAPIFormats = [
+    protected static array $openAPIFormats = [
        'id' => 'int64',
        'name' => null,
        'category' => null,
@@ -85,7 +86,7 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
      * Array of nullable properties. Used for (de)serialization
      *
-      * @var boolean[]
+      * @var array<string, bool>
      */
    protected static array $openAPINullables = [
        'id' => false,
@@ -99,16 +100,16 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
      * If a nullable field gets set to null, insert it here
      *
-      * @var boolean[]
+      * @var array<string, bool>
      */
    protected array $openAPINullablesSetToNull = [];

    /**
     * Array of property to type mappings. Used for (de)serialization
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function openAPITypes()
+    public static function openAPITypes(): array
    {
        return self::$openAPITypes;
    }
@@ -116,9 +117,9 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of property to format mappings. Used for (de)serialization
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function openAPIFormats()
+    public static function openAPIFormats(): array
    {
        return self::$openAPIFormats;
    }
@@ -126,7 +127,7 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of nullable properties
     *
-     * @return array
+     * @return array<string, bool>
     */
    protected static function openAPINullables(): array
    {
@@ -136,7 +137,7 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of nullable field names deliberately set to null
     *
-     * @return boolean[]
+     * @return array<string, bool>
     */
    private function getOpenAPINullablesSetToNull(): array
    {
@@ -146,7 +147,7 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Setter - Array of nullable field names deliberately set to null
     *
-     * @param boolean[] $openAPINullablesSetToNull
+     * @param array<string, bool> $openAPINullablesSetToNull
     */
    private function setOpenAPINullablesSetToNull(array $openAPINullablesSetToNull): void
    {
@@ -179,9 +180,9 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
     * Array of attributes where the key is the local name,
     * and the value is the original name
     *
-     * @var string[]
+     * @var array<string, string>
     */
-    protected static $attributeMap = [
+    protected static array $attributeMap = [
        'id' => 'id',
        'name' => 'name',
        'category' => 'category',
@@ -193,9 +194,9 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of attributes to setter functions (for deserialization of responses)
     *
-     * @var string[]
+     * @var array<string, string>
     */
-    protected static $setters = [
+    protected static array $setters = [
        'id' => 'setId',
        'name' => 'setName',
        'category' => 'setCategory',
@@ -207,9 +208,9 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of attributes to getter functions (for serialization of requests)
     *
-     * @var string[]
+     * @var array<string, string>
     */
-    protected static $getters = [
+    protected static array $getters = [
        'id' => 'getId',
        'name' => 'getName',
        'category' => 'getCategory',
@@ -222,9 +223,9 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
     * Array of attributes where the key is the local name,
     * and the value is the original name
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function attributeMap()
+    public static function attributeMap(): array
    {
        return self::$attributeMap;
    }
@@ -232,9 +233,9 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of attributes to setter functions (for deserialization of responses)
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function setters()
+    public static function setters(): array
    {
        return self::$setters;
    }
@@ -242,9 +243,9 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of attributes to getter functions (for serialization of requests)
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function getters()
+    public static function getters(): array
    {
        return self::$getters;
    }
@@ -254,7 +255,7 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string
     */
-    public function getModelName()
+    public function getModelName(): string
    {
        return self::$openAPIModelName;
    }
@@ -280,15 +281,14 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Associative array for storing property values
     *
-     * @var mixed[]
+     * @var array
     */
-    protected $container = [];
+    protected array $container = [];

    /**
     * Constructor
     *
-     * @param mixed[] $data Associated array of property values
-     *                      initializing the model
+     * @param array $data Associated array of property values initializing the model
     */
    public function __construct(array $data = null)
    {
@@ -309,7 +309,7 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
    * @param array  $fields
    * @param mixed  $defaultValue
    */
-    private function setIfExists(string $variableName, array $fields, $defaultValue): void
+    private function setIfExists(string $variableName, array $fields, mixed $defaultValue): void
    {
        if (self::isNullable($variableName) && array_key_exists($variableName, $fields) && is_null($fields[$variableName])) {
            $this->openAPINullablesSetToNull[] = $variableName;
@@ -321,9 +321,9 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Show all the invalid properties with reasons.
     *
-     * @return array invalid properties with reasons
+     * @return string[] invalid properties with reasons
     */
-    public function listInvalidProperties()
+    public function listInvalidProperties(): array
    {
        $invalidProperties = [];

@@ -351,7 +351,7 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return bool True if all properties are valid
     */
-    public function valid()
+    public function valid(): bool
    {
        return count($this->listInvalidProperties()) === 0;
    }
@@ -362,7 +362,7 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return int|null
     */
-    public function getId()
+    public function getId(): ?int
    {
        return $this->container['id'];
    }
@@ -372,12 +372,12 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @param int|null $id id
     *
-     * @return self
+     * @return $this
     */
-    public function setId($id)
+    public function setId(?int $id): static
    {
        if (is_null($id)) {
-            throw new \InvalidArgumentException('non-nullable id cannot be null');
+            throw new InvalidArgumentException('non-nullable id cannot be null');
        }
        $this->container['id'] = $id;

@@ -389,7 +389,7 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string
     */
-    public function getName()
+    public function getName(): string
    {
        return $this->container['name'];
    }
@@ -399,12 +399,12 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @param string $name name
     *
-     * @return self
+     * @return $this
     */
-    public function setName($name)
+    public function setName(string $name): static
    {
        if (is_null($name)) {
-            throw new \InvalidArgumentException('non-nullable name cannot be null');
+            throw new InvalidArgumentException('non-nullable name cannot be null');
        }
        $this->container['name'] = $name;

@@ -416,7 +416,7 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return \OpenAPI\Client\Model\Category|null
     */
-    public function getCategory()
+    public function getCategory(): ?\OpenAPI\Client\Model\Category
    {
        return $this->container['category'];
    }
@@ -426,12 +426,12 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @param \OpenAPI\Client\Model\Category|null $category category
     *
-     * @return self
+     * @return $this
     */
-    public function setCategory($category)
+    public function setCategory(?\OpenAPI\Client\Model\Category $category): static
    {
        if (is_null($category)) {
-            throw new \InvalidArgumentException('non-nullable category cannot be null');
+            throw new InvalidArgumentException('non-nullable category cannot be null');
        }
        $this->container['category'] = $category;

@@ -443,7 +443,7 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string[]
     */
-    public function getPhotoUrls()
+    public function getPhotoUrls(): array
    {
        return $this->container['photo_urls'];
    }
@@ -453,12 +453,12 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @param string[] $photo_urls photo_urls
     *
-     * @return self
+     * @return $this
     */
-    public function setPhotoUrls($photo_urls)
+    public function setPhotoUrls(array $photo_urls): static
    {
        if (is_null($photo_urls)) {
-            throw new \InvalidArgumentException('non-nullable photo_urls cannot be null');
+            throw new InvalidArgumentException('non-nullable photo_urls cannot be null');
        }
        $this->container['photo_urls'] = $photo_urls;

@@ -470,7 +470,7 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return \OpenAPI\Client\Model\Tag[]|null
     */
-    public function getTags()
+    public function getTags(): ?array
    {
        return $this->container['tags'];
    }
@@ -480,12 +480,12 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @param \OpenAPI\Client\Model\Tag[]|null $tags tags
     *
-     * @return self
+     * @return $this
     */
-    public function setTags($tags)
+    public function setTags(?array $tags): static
    {
        if (is_null($tags)) {
-            throw new \InvalidArgumentException('non-nullable tags cannot be null');
+            throw new InvalidArgumentException('non-nullable tags cannot be null');
        }
        $this->container['tags'] = $tags;

@@ -497,7 +497,7 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string|null
     */
-    public function getStatus()
+    public function getStatus(): ?string
    {
        return $this->container['status'];
    }
@@ -507,16 +507,16 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @param string|null $status pet status in the store
     *
-     * @return self
+     * @return $this
     */
-    public function setStatus($status)
+    public function setStatus(?string $status): static
    {
        if (is_null($status)) {
-            throw new \InvalidArgumentException('non-nullable status cannot be null');
+            throw new InvalidArgumentException('non-nullable status cannot be null');
        }
        $allowedValues = $this->getStatusAllowableValues();
        if (!in_array($status, $allowedValues, true)) {
-            throw new \InvalidArgumentException(
+            throw new InvalidArgumentException(
                sprintf(
                    "Invalid value '%s' for 'status', must be one of '%s'",
                    $status,
@@ -535,7 +535,7 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return boolean
     */
-    public function offsetExists($offset): bool
+    public function offsetExists(mixed $offset): bool
    {
        return isset($this->container[$offset]);
    }
@@ -547,8 +547,8 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return mixed|null
     */
-    #[\ReturnTypeWillChange]
-    public function offsetGet($offset)
+    #[ReturnTypeWillChange]
+    public function offsetGet(mixed $offset): mixed
    {
        return $this->container[$offset] ?? null;
    }
@@ -561,7 +561,7 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return void
     */
-    public function offsetSet($offset, $value): void
+    public function offsetSet(mixed $offset, mixed $value): void
    {
        if (is_null($offset)) {
            $this->container[] = $value;
@@ -577,7 +577,7 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return void
     */
-    public function offsetUnset($offset): void
+    public function offsetUnset(mixed $offset): void
    {
        unset($this->container[$offset]);
    }
@@ -589,8 +589,8 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
     * @return mixed Returns data which can be serialized by json_encode(), which is a value
     * of any type other than a resource.
     */
-    #[\ReturnTypeWillChange]
-    public function jsonSerialize()
+    #[ReturnTypeWillChange]
+    public function jsonSerialize(): mixed
    {
       return ObjectSerializer::sanitizeForSerialization($this);
    }
@@ -600,7 +600,7 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string
     */
-    public function __toString()
+    public function __toString(): string
    {
        return json_encode(
            ObjectSerializer::sanitizeForSerialization($this),
@@ -613,7 +613,7 @@ class Pet implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string
     */
-    public function toHeaderValue()
+    public function toHeaderValue(): string
    {
        return json_encode(ObjectSerializer::sanitizeForSerialization($this));
    }
--- a/samples/client/echo_api/php-nextgen/src/Model/Query.php
+++ b/samples/client/echo_api/php-nextgen/src/Model/Query.php
@@ -29,8 +29,11 @@

 namespace OpenAPI\Client\Model;

-use \ArrayAccess;
-use \OpenAPI\Client\ObjectSerializer;
+use ArrayAccess;
+use JsonSerializable;
+use InvalidArgumentException;
+use ReturnTypeWillChange;
+use OpenAPI\Client\ObjectSerializer;

 /**
 * Query Class Doc Comment
@@ -39,9 +42,9 @@ use \OpenAPI\Client\ObjectSerializer;
 * @package  OpenAPI\Client
 * @author   OpenAPI Generator team
 * @link     https://openapi-generator.tech
- * @implements \ArrayAccess<string, mixed>
+ * @implements ArrayAccess<string, mixed>
 */
-class Query implements ModelInterface, ArrayAccess, \JsonSerializable
+class Query implements ModelInterface, ArrayAccess, JsonSerializable
 {
    public const DISCRIMINATOR = null;

@@ -50,14 +53,14 @@ class Query implements ModelInterface, ArrayAccess, \JsonSerializable
      *
      * @var string
      */
-    protected static $openAPIModelName = 'Query';
+    protected static string $openAPIModelName = 'Query';

    /**
      * Array of property to type mappings. Used for (de)serialization
      *
-      * @var string[]
+      * @var array<string, string>
      */
-    protected static $openAPITypes = [
+    protected static array $openAPITypes = [
        'id' => 'int',
        'outcomes' => 'string[]'
    ];
@@ -65,11 +68,9 @@ class Query implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
      * Array of property to format mappings. Used for (de)serialization
      *
-      * @var string[]
-      * @phpstan-var array<string, string|null>
-      * @psalm-var array<string, string|null>
+      * @var array<string, string|null>
      */
-    protected static $openAPIFormats = [
+    protected static array $openAPIFormats = [
        'id' => 'int64',
        'outcomes' => null
    ];
@@ -77,7 +78,7 @@ class Query implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
      * Array of nullable properties. Used for (de)serialization
      *
-      * @var boolean[]
+      * @var array<string, bool>
      */
    protected static array $openAPINullables = [
        'id' => false,
@@ -87,16 +88,16 @@ class Query implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
      * If a nullable field gets set to null, insert it here
      *
-      * @var boolean[]
+      * @var array<string, bool>
      */
    protected array $openAPINullablesSetToNull = [];

    /**
     * Array of property to type mappings. Used for (de)serialization
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function openAPITypes()
+    public static function openAPITypes(): array
    {
        return self::$openAPITypes;
    }
@@ -104,9 +105,9 @@ class Query implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of property to format mappings. Used for (de)serialization
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function openAPIFormats()
+    public static function openAPIFormats(): array
    {
        return self::$openAPIFormats;
    }
@@ -114,7 +115,7 @@ class Query implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of nullable properties
     *
-     * @return array
+     * @return array<string, bool>
     */
    protected static function openAPINullables(): array
    {
@@ -124,7 +125,7 @@ class Query implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of nullable field names deliberately set to null
     *
-     * @return boolean[]
+     * @return array<string, bool>
     */
    private function getOpenAPINullablesSetToNull(): array
    {
@@ -134,7 +135,7 @@ class Query implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Setter - Array of nullable field names deliberately set to null
     *
-     * @param boolean[] $openAPINullablesSetToNull
+     * @param array<string, bool> $openAPINullablesSetToNull
     */
    private function setOpenAPINullablesSetToNull(array $openAPINullablesSetToNull): void
    {
@@ -167,9 +168,9 @@ class Query implements ModelInterface, ArrayAccess, \JsonSerializable
     * Array of attributes where the key is the local name,
     * and the value is the original name
     *
-     * @var string[]
+     * @var array<string, string>
     */
-    protected static $attributeMap = [
+    protected static array $attributeMap = [
        'id' => 'id',
        'outcomes' => 'outcomes'
    ];
@@ -177,9 +178,9 @@ class Query implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of attributes to setter functions (for deserialization of responses)
     *
-     * @var string[]
+     * @var array<string, string>
     */
-    protected static $setters = [
+    protected static array $setters = [
        'id' => 'setId',
        'outcomes' => 'setOutcomes'
    ];
@@ -187,9 +188,9 @@ class Query implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of attributes to getter functions (for serialization of requests)
     *
-     * @var string[]
+     * @var array<string, string>
     */
-    protected static $getters = [
+    protected static array $getters = [
        'id' => 'getId',
        'outcomes' => 'getOutcomes'
    ];
@@ -198,9 +199,9 @@ class Query implements ModelInterface, ArrayAccess, \JsonSerializable
     * Array of attributes where the key is the local name,
     * and the value is the original name
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function attributeMap()
+    public static function attributeMap(): array
    {
        return self::$attributeMap;
    }
@@ -208,9 +209,9 @@ class Query implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of attributes to setter functions (for deserialization of responses)
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function setters()
+    public static function setters(): array
    {
        return self::$setters;
    }
@@ -218,9 +219,9 @@ class Query implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of attributes to getter functions (for serialization of requests)
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function getters()
+    public static function getters(): array
    {
        return self::$getters;
    }
@@ -230,7 +231,7 @@ class Query implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string
     */
-    public function getModelName()
+    public function getModelName(): string
    {
        return self::$openAPIModelName;
    }
@@ -256,20 +257,19 @@ class Query implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Associative array for storing property values
     *
-     * @var mixed[]
+     * @var array
     */
-    protected $container = [];
+    protected array $container = [];

    /**
     * Constructor
     *
-     * @param mixed[] $data Associated array of property values
-     *                      initializing the model
+     * @param array $data Associated array of property values initializing the model
     */
    public function __construct(array $data = null)
    {
        $this->setIfExists('id', $data ?? [], null);
-        $this->setIfExists('outcomes', $data ?? [], null);
+        $this->setIfExists('outcomes', $data ?? [], [["SUCCESS","FAILURE"]]);
    }

    /**
@@ -281,7 +281,7 @@ class Query implements ModelInterface, ArrayAccess, \JsonSerializable
    * @param array  $fields
    * @param mixed  $defaultValue
    */
-    private function setIfExists(string $variableName, array $fields, $defaultValue): void
+    private function setIfExists(string $variableName, array $fields, mixed $defaultValue): void
    {
        if (self::isNullable($variableName) && array_key_exists($variableName, $fields) && is_null($fields[$variableName])) {
            $this->openAPINullablesSetToNull[] = $variableName;
@@ -293,9 +293,9 @@ class Query implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Show all the invalid properties with reasons.
     *
-     * @return array invalid properties with reasons
+     * @return string[] invalid properties with reasons
     */
-    public function listInvalidProperties()
+    public function listInvalidProperties(): array
    {
        $invalidProperties = [];

@@ -308,7 +308,7 @@ class Query implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return bool True if all properties are valid
     */
-    public function valid()
+    public function valid(): bool
    {
        return count($this->listInvalidProperties()) === 0;
    }
@@ -319,7 +319,7 @@ class Query implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return int|null
     */
-    public function getId()
+    public function getId(): ?int
    {
        return $this->container['id'];
    }
@@ -329,12 +329,12 @@ class Query implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @param int|null $id Query
     *
-     * @return self
+     * @return $this
     */
-    public function setId($id)
+    public function setId(?int $id): static
    {
        if (is_null($id)) {
-            throw new \InvalidArgumentException('non-nullable id cannot be null');
+            throw new InvalidArgumentException('non-nullable id cannot be null');
        }
        $this->container['id'] = $id;

@@ -346,7 +346,7 @@ class Query implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string[]|null
     */
-    public function getOutcomes()
+    public function getOutcomes(): ?array
    {
        return $this->container['outcomes'];
    }
@@ -356,16 +356,16 @@ class Query implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @param string[]|null $outcomes outcomes
     *
-     * @return self
+     * @return $this
     */
-    public function setOutcomes($outcomes)
+    public function setOutcomes(?array $outcomes): static
    {
        if (is_null($outcomes)) {
-            throw new \InvalidArgumentException('non-nullable outcomes cannot be null');
+            throw new InvalidArgumentException('non-nullable outcomes cannot be null');
        }
        $allowedValues = $this->getOutcomesAllowableValues();
        if (array_diff($outcomes, $allowedValues)) {
-            throw new \InvalidArgumentException(
+            throw new InvalidArgumentException(
                sprintf(
                    "Invalid value for 'outcomes', must be one of '%s'",
                    implode("', '", $allowedValues)
@@ -383,7 +383,7 @@ class Query implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return boolean
     */
-    public function offsetExists($offset): bool
+    public function offsetExists(mixed $offset): bool
    {
        return isset($this->container[$offset]);
    }
@@ -395,8 +395,8 @@ class Query implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return mixed|null
     */
-    #[\ReturnTypeWillChange]
-    public function offsetGet($offset)
+    #[ReturnTypeWillChange]
+    public function offsetGet(mixed $offset): mixed
    {
        return $this->container[$offset] ?? null;
    }
@@ -409,7 +409,7 @@ class Query implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return void
     */
-    public function offsetSet($offset, $value): void
+    public function offsetSet(mixed $offset, mixed $value): void
    {
        if (is_null($offset)) {
            $this->container[] = $value;
@@ -425,7 +425,7 @@ class Query implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return void
     */
-    public function offsetUnset($offset): void
+    public function offsetUnset(mixed $offset): void
    {
        unset($this->container[$offset]);
    }
@@ -437,8 +437,8 @@ class Query implements ModelInterface, ArrayAccess, \JsonSerializable
     * @return mixed Returns data which can be serialized by json_encode(), which is a value
     * of any type other than a resource.
     */
-    #[\ReturnTypeWillChange]
-    public function jsonSerialize()
+    #[ReturnTypeWillChange]
+    public function jsonSerialize(): mixed
    {
       return ObjectSerializer::sanitizeForSerialization($this);
    }
@@ -448,7 +448,7 @@ class Query implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string
     */
-    public function __toString()
+    public function __toString(): string
    {
        return json_encode(
            ObjectSerializer::sanitizeForSerialization($this),
@@ -461,7 +461,7 @@ class Query implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string
     */
-    public function toHeaderValue()
+    public function toHeaderValue(): string
    {
        return json_encode(ObjectSerializer::sanitizeForSerialization($this));
    }
--- a/samples/client/echo_api/php-nextgen/src/Model/StringEnumRef.php
+++ b/samples/client/echo_api/php-nextgen/src/Model/StringEnumRef.php
@@ -28,7 +28,6 @@
 */

 namespace OpenAPI\Client\Model;
-use \OpenAPI\Client\ObjectSerializer;

 /**
 * StringEnumRef Class Doc Comment
--- a/samples/client/echo_api/php-nextgen/src/Model/Tag.php
+++ b/samples/client/echo_api/php-nextgen/src/Model/Tag.php
@@ -29,8 +29,11 @@

 namespace OpenAPI\Client\Model;

-use \ArrayAccess;
-use \OpenAPI\Client\ObjectSerializer;
+use ArrayAccess;
+use JsonSerializable;
+use InvalidArgumentException;
+use ReturnTypeWillChange;
+use OpenAPI\Client\ObjectSerializer;

 /**
 * Tag Class Doc Comment
@@ -39,9 +42,9 @@ use \OpenAPI\Client\ObjectSerializer;
 * @package  OpenAPI\Client
 * @author   OpenAPI Generator team
 * @link     https://openapi-generator.tech
- * @implements \ArrayAccess<string, mixed>
+ * @implements ArrayAccess<string, mixed>
 */
-class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
+class Tag implements ModelInterface, ArrayAccess, JsonSerializable
 {
    public const DISCRIMINATOR = null;

@@ -50,14 +53,14 @@ class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
      *
      * @var string
      */
-    protected static $openAPIModelName = 'Tag';
+    protected static string $openAPIModelName = 'Tag';

    /**
      * Array of property to type mappings. Used for (de)serialization
      *
-      * @var string[]
+      * @var array<string, string>
      */
-    protected static $openAPITypes = [
+    protected static array $openAPITypes = [
        'id' => 'int',
        'name' => 'string'
    ];
@@ -65,11 +68,9 @@ class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
      * Array of property to format mappings. Used for (de)serialization
      *
-      * @var string[]
-      * @phpstan-var array<string, string|null>
-      * @psalm-var array<string, string|null>
+      * @var array<string, string|null>
      */
-    protected static $openAPIFormats = [
+    protected static array $openAPIFormats = [
        'id' => 'int64',
        'name' => null
    ];
@@ -77,7 +78,7 @@ class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
      * Array of nullable properties. Used for (de)serialization
      *
-      * @var boolean[]
+      * @var array<string, bool>
      */
    protected static array $openAPINullables = [
        'id' => false,
@@ -87,16 +88,16 @@ class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
      * If a nullable field gets set to null, insert it here
      *
-      * @var boolean[]
+      * @var array<string, bool>
      */
    protected array $openAPINullablesSetToNull = [];

    /**
     * Array of property to type mappings. Used for (de)serialization
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function openAPITypes()
+    public static function openAPITypes(): array
    {
        return self::$openAPITypes;
    }
@@ -104,9 +105,9 @@ class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of property to format mappings. Used for (de)serialization
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function openAPIFormats()
+    public static function openAPIFormats(): array
    {
        return self::$openAPIFormats;
    }
@@ -114,7 +115,7 @@ class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of nullable properties
     *
-     * @return array
+     * @return array<string, bool>
     */
    protected static function openAPINullables(): array
    {
@@ -124,7 +125,7 @@ class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of nullable field names deliberately set to null
     *
-     * @return boolean[]
+     * @return array<string, bool>
     */
    private function getOpenAPINullablesSetToNull(): array
    {
@@ -134,7 +135,7 @@ class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Setter - Array of nullable field names deliberately set to null
     *
-     * @param boolean[] $openAPINullablesSetToNull
+     * @param array<string, bool> $openAPINullablesSetToNull
     */
    private function setOpenAPINullablesSetToNull(array $openAPINullablesSetToNull): void
    {
@@ -167,9 +168,9 @@ class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
     * Array of attributes where the key is the local name,
     * and the value is the original name
     *
-     * @var string[]
+     * @var array<string, string>
     */
-    protected static $attributeMap = [
+    protected static array $attributeMap = [
        'id' => 'id',
        'name' => 'name'
    ];
@@ -177,9 +178,9 @@ class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of attributes to setter functions (for deserialization of responses)
     *
-     * @var string[]
+     * @var array<string, string>
     */
-    protected static $setters = [
+    protected static array $setters = [
        'id' => 'setId',
        'name' => 'setName'
    ];
@@ -187,9 +188,9 @@ class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of attributes to getter functions (for serialization of requests)
     *
-     * @var string[]
+     * @var array<string, string>
     */
-    protected static $getters = [
+    protected static array $getters = [
        'id' => 'getId',
        'name' => 'getName'
    ];
@@ -198,9 +199,9 @@ class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
     * Array of attributes where the key is the local name,
     * and the value is the original name
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function attributeMap()
+    public static function attributeMap(): array
    {
        return self::$attributeMap;
    }
@@ -208,9 +209,9 @@ class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of attributes to setter functions (for deserialization of responses)
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function setters()
+    public static function setters(): array
    {
        return self::$setters;
    }
@@ -218,9 +219,9 @@ class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Array of attributes to getter functions (for serialization of requests)
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function getters()
+    public static function getters(): array
    {
        return self::$getters;
    }
@@ -230,7 +231,7 @@ class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string
     */
-    public function getModelName()
+    public function getModelName(): string
    {
        return self::$openAPIModelName;
    }
@@ -239,15 +240,14 @@ class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Associative array for storing property values
     *
-     * @var mixed[]
+     * @var array
     */
-    protected $container = [];
+    protected array $container = [];

    /**
     * Constructor
     *
-     * @param mixed[] $data Associated array of property values
-     *                      initializing the model
+     * @param array $data Associated array of property values initializing the model
     */
    public function __construct(array $data = null)
    {
@@ -264,7 +264,7 @@ class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
    * @param array  $fields
    * @param mixed  $defaultValue
    */
-    private function setIfExists(string $variableName, array $fields, $defaultValue): void
+    private function setIfExists(string $variableName, array $fields, mixed $defaultValue): void
    {
        if (self::isNullable($variableName) && array_key_exists($variableName, $fields) && is_null($fields[$variableName])) {
            $this->openAPINullablesSetToNull[] = $variableName;
@@ -276,9 +276,9 @@ class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
    /**
     * Show all the invalid properties with reasons.
     *
-     * @return array invalid properties with reasons
+     * @return string[] invalid properties with reasons
     */
-    public function listInvalidProperties()
+    public function listInvalidProperties(): array
    {
        $invalidProperties = [];

@@ -291,7 +291,7 @@ class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return bool True if all properties are valid
     */
-    public function valid()
+    public function valid(): bool
    {
        return count($this->listInvalidProperties()) === 0;
    }
@@ -302,7 +302,7 @@ class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return int|null
     */
-    public function getId()
+    public function getId(): ?int
    {
        return $this->container['id'];
    }
@@ -312,12 +312,12 @@ class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @param int|null $id id
     *
-     * @return self
+     * @return $this
     */
-    public function setId($id)
+    public function setId(?int $id): static
    {
        if (is_null($id)) {
-            throw new \InvalidArgumentException('non-nullable id cannot be null');
+            throw new InvalidArgumentException('non-nullable id cannot be null');
        }
        $this->container['id'] = $id;

@@ -329,7 +329,7 @@ class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string|null
     */
-    public function getName()
+    public function getName(): ?string
    {
        return $this->container['name'];
    }
@@ -339,12 +339,12 @@ class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @param string|null $name name
     *
-     * @return self
+     * @return $this
     */
-    public function setName($name)
+    public function setName(?string $name): static
    {
        if (is_null($name)) {
-            throw new \InvalidArgumentException('non-nullable name cannot be null');
+            throw new InvalidArgumentException('non-nullable name cannot be null');
        }
        $this->container['name'] = $name;

@@ -357,7 +357,7 @@ class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return boolean
     */
-    public function offsetExists($offset): bool
+    public function offsetExists(mixed $offset): bool
    {
        return isset($this->container[$offset]);
    }
@@ -369,8 +369,8 @@ class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return mixed|null
     */
-    #[\ReturnTypeWillChange]
-    public function offsetGet($offset)
+    #[ReturnTypeWillChange]
+    public function offsetGet(mixed $offset): mixed
    {
        return $this->container[$offset] ?? null;
    }
@@ -383,7 +383,7 @@ class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return void
     */
-    public function offsetSet($offset, $value): void
+    public function offsetSet(mixed $offset, mixed $value): void
    {
        if (is_null($offset)) {
            $this->container[] = $value;
@@ -399,7 +399,7 @@ class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return void
     */
-    public function offsetUnset($offset): void
+    public function offsetUnset(mixed $offset): void
    {
        unset($this->container[$offset]);
    }
@@ -411,8 +411,8 @@ class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
     * @return mixed Returns data which can be serialized by json_encode(), which is a value
     * of any type other than a resource.
     */
-    #[\ReturnTypeWillChange]
-    public function jsonSerialize()
+    #[ReturnTypeWillChange]
+    public function jsonSerialize(): mixed
    {
       return ObjectSerializer::sanitizeForSerialization($this);
    }
@@ -422,7 +422,7 @@ class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string
     */
-    public function __toString()
+    public function __toString(): string
    {
        return json_encode(
            ObjectSerializer::sanitizeForSerialization($this),
@@ -435,7 +435,7 @@ class Tag implements ModelInterface, ArrayAccess, \JsonSerializable
     *
     * @return string
     */
-    public function toHeaderValue()
+    public function toHeaderValue(): string
    {
        return json_encode(ObjectSerializer::sanitizeForSerialization($this));
    }
--- a/samples/client/echo_api/php-nextgen/src/Model/TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter.php
+++ b/samples/client/echo_api/php-nextgen/src/Model/TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter.php
@@ -29,8 +29,11 @@

 namespace OpenAPI\Client\Model;

-use \ArrayAccess;
-use \OpenAPI\Client\ObjectSerializer;
+use ArrayAccess;
+use JsonSerializable;
+use InvalidArgumentException;
+use ReturnTypeWillChange;
+use OpenAPI\Client\ObjectSerializer;

 /**
 * TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter Class Doc Comment
@@ -39,9 +42,9 @@ use \OpenAPI\Client\ObjectSerializer;
 * @package  OpenAPI\Client
 * @author   OpenAPI Generator team
 * @link     https://openapi-generator.tech
- * @implements \ArrayAccess<string, mixed>
+ * @implements ArrayAccess<string, mixed>
 */
-class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter implements ModelInterface, ArrayAccess, \JsonSerializable
+class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter implements ModelInterface, ArrayAccess, JsonSerializable
 {
    public const DISCRIMINATOR = null;

@@ -50,14 +53,14 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
      *
      * @var string
      */
-    protected static $openAPIModelName = 'test_query_style_deepObject_explode_true_object_allOf_query_object_parameter';
+    protected static string $openAPIModelName = 'test_query_style_deepObject_explode_true_object_allOf_query_object_parameter';

    /**
      * Array of property to type mappings. Used for (de)serialization
      *
-      * @var string[]
+      * @var array<string, string>
      */
-    protected static $openAPITypes = [
+    protected static array $openAPITypes = [
        'size' => 'string',
        'color' => 'string',
        'id' => 'int',
@@ -67,11 +70,9 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
    /**
      * Array of property to format mappings. Used for (de)serialization
      *
-      * @var string[]
-      * @phpstan-var array<string, string|null>
-      * @psalm-var array<string, string|null>
+      * @var array<string, string|null>
      */
-    protected static $openAPIFormats = [
+    protected static array $openAPIFormats = [
        'size' => null,
        'color' => null,
        'id' => 'int64',
@@ -81,7 +82,7 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
    /**
      * Array of nullable properties. Used for (de)serialization
      *
-      * @var boolean[]
+      * @var array<string, bool>
      */
    protected static array $openAPINullables = [
        'size' => false,
@@ -93,16 +94,16 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
    /**
      * If a nullable field gets set to null, insert it here
      *
-      * @var boolean[]
+      * @var array<string, bool>
      */
    protected array $openAPINullablesSetToNull = [];

    /**
     * Array of property to type mappings. Used for (de)serialization
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function openAPITypes()
+    public static function openAPITypes(): array
    {
        return self::$openAPITypes;
    }
@@ -110,9 +111,9 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
    /**
     * Array of property to format mappings. Used for (de)serialization
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function openAPIFormats()
+    public static function openAPIFormats(): array
    {
        return self::$openAPIFormats;
    }
@@ -120,7 +121,7 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
    /**
     * Array of nullable properties
     *
-     * @return array
+     * @return array<string, bool>
     */
    protected static function openAPINullables(): array
    {
@@ -130,7 +131,7 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
    /**
     * Array of nullable field names deliberately set to null
     *
-     * @return boolean[]
+     * @return array<string, bool>
     */
    private function getOpenAPINullablesSetToNull(): array
    {
@@ -140,7 +141,7 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
    /**
     * Setter - Array of nullable field names deliberately set to null
     *
-     * @param boolean[] $openAPINullablesSetToNull
+     * @param array<string, bool> $openAPINullablesSetToNull
     */
    private function setOpenAPINullablesSetToNull(array $openAPINullablesSetToNull): void
    {
@@ -173,9 +174,9 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
     * Array of attributes where the key is the local name,
     * and the value is the original name
     *
-     * @var string[]
+     * @var array<string, string>
     */
-    protected static $attributeMap = [
+    protected static array $attributeMap = [
        'size' => 'size',
        'color' => 'color',
        'id' => 'id',
@@ -185,9 +186,9 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
    /**
     * Array of attributes to setter functions (for deserialization of responses)
     *
-     * @var string[]
+     * @var array<string, string>
     */
-    protected static $setters = [
+    protected static array $setters = [
        'size' => 'setSize',
        'color' => 'setColor',
        'id' => 'setId',
@@ -197,9 +198,9 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
    /**
     * Array of attributes to getter functions (for serialization of requests)
     *
-     * @var string[]
+     * @var array<string, string>
     */
-    protected static $getters = [
+    protected static array $getters = [
        'size' => 'getSize',
        'color' => 'getColor',
        'id' => 'getId',
@@ -210,9 +211,9 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
     * Array of attributes where the key is the local name,
     * and the value is the original name
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function attributeMap()
+    public static function attributeMap(): array
    {
        return self::$attributeMap;
    }
@@ -220,9 +221,9 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
    /**
     * Array of attributes to setter functions (for deserialization of responses)
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function setters()
+    public static function setters(): array
    {
        return self::$setters;
    }
@@ -230,9 +231,9 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
    /**
     * Array of attributes to getter functions (for serialization of requests)
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function getters()
+    public static function getters(): array
    {
        return self::$getters;
    }
@@ -242,7 +243,7 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
     *
     * @return string
     */
-    public function getModelName()
+    public function getModelName(): string
    {
        return self::$openAPIModelName;
    }
@@ -251,15 +252,14 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
    /**
     * Associative array for storing property values
     *
-     * @var mixed[]
+     * @var array
     */
-    protected $container = [];
+    protected array $container = [];

    /**
     * Constructor
     *
-     * @param mixed[] $data Associated array of property values
-     *                      initializing the model
+     * @param array $data Associated array of property values initializing the model
     */
    public function __construct(array $data = null)
    {
@@ -278,7 +278,7 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
    * @param array  $fields
    * @param mixed  $defaultValue
    */
-    private function setIfExists(string $variableName, array $fields, $defaultValue): void
+    private function setIfExists(string $variableName, array $fields, mixed $defaultValue): void
    {
        if (self::isNullable($variableName) && array_key_exists($variableName, $fields) && is_null($fields[$variableName])) {
            $this->openAPINullablesSetToNull[] = $variableName;
@@ -290,9 +290,9 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
    /**
     * Show all the invalid properties with reasons.
     *
-     * @return array invalid properties with reasons
+     * @return string[] invalid properties with reasons
     */
-    public function listInvalidProperties()
+    public function listInvalidProperties(): array
    {
        $invalidProperties = [];

@@ -305,7 +305,7 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
     *
     * @return bool True if all properties are valid
     */
-    public function valid()
+    public function valid(): bool
    {
        return count($this->listInvalidProperties()) === 0;
    }
@@ -316,7 +316,7 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
     *
     * @return string|null
     */
-    public function getSize()
+    public function getSize(): ?string
    {
        return $this->container['size'];
    }
@@ -326,12 +326,12 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
     *
     * @param string|null $size size
     *
-     * @return self
+     * @return $this
     */
-    public function setSize($size)
+    public function setSize(?string $size): static
    {
        if (is_null($size)) {
-            throw new \InvalidArgumentException('non-nullable size cannot be null');
+            throw new InvalidArgumentException('non-nullable size cannot be null');
        }
        $this->container['size'] = $size;

@@ -343,7 +343,7 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
     *
     * @return string|null
     */
-    public function getColor()
+    public function getColor(): ?string
    {
        return $this->container['color'];
    }
@@ -353,12 +353,12 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
     *
     * @param string|null $color color
     *
-     * @return self
+     * @return $this
     */
-    public function setColor($color)
+    public function setColor(?string $color): static
    {
        if (is_null($color)) {
-            throw new \InvalidArgumentException('non-nullable color cannot be null');
+            throw new InvalidArgumentException('non-nullable color cannot be null');
        }
        $this->container['color'] = $color;

@@ -370,7 +370,7 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
     *
     * @return int|null
     */
-    public function getId()
+    public function getId(): ?int
    {
        return $this->container['id'];
    }
@@ -380,12 +380,12 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
     *
     * @param int|null $id id
     *
-     * @return self
+     * @return $this
     */
-    public function setId($id)
+    public function setId(?int $id): static
    {
        if (is_null($id)) {
-            throw new \InvalidArgumentException('non-nullable id cannot be null');
+            throw new InvalidArgumentException('non-nullable id cannot be null');
        }
        $this->container['id'] = $id;

@@ -397,7 +397,7 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
     *
     * @return string|null
     */
-    public function getName()
+    public function getName(): ?string
    {
        return $this->container['name'];
    }
@@ -407,12 +407,12 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
     *
     * @param string|null $name name
     *
-     * @return self
+     * @return $this
     */
-    public function setName($name)
+    public function setName(?string $name): static
    {
        if (is_null($name)) {
-            throw new \InvalidArgumentException('non-nullable name cannot be null');
+            throw new InvalidArgumentException('non-nullable name cannot be null');
        }
        $this->container['name'] = $name;

@@ -425,7 +425,7 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
     *
     * @return boolean
     */
-    public function offsetExists($offset): bool
+    public function offsetExists(mixed $offset): bool
    {
        return isset($this->container[$offset]);
    }
@@ -437,8 +437,8 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
     *
     * @return mixed|null
     */
-    #[\ReturnTypeWillChange]
-    public function offsetGet($offset)
+    #[ReturnTypeWillChange]
+    public function offsetGet(mixed $offset): mixed
    {
        return $this->container[$offset] ?? null;
    }
@@ -451,7 +451,7 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
     *
     * @return void
     */
-    public function offsetSet($offset, $value): void
+    public function offsetSet(mixed $offset, mixed $value): void
    {
        if (is_null($offset)) {
            $this->container[] = $value;
@@ -467,7 +467,7 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
     *
     * @return void
     */
-    public function offsetUnset($offset): void
+    public function offsetUnset(mixed $offset): void
    {
        unset($this->container[$offset]);
    }
@@ -479,8 +479,8 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
     * @return mixed Returns data which can be serialized by json_encode(), which is a value
     * of any type other than a resource.
     */
-    #[\ReturnTypeWillChange]
-    public function jsonSerialize()
+    #[ReturnTypeWillChange]
+    public function jsonSerialize(): mixed
    {
       return ObjectSerializer::sanitizeForSerialization($this);
    }
@@ -490,7 +490,7 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
     *
     * @return string
     */
-    public function __toString()
+    public function __toString(): string
    {
        return json_encode(
            ObjectSerializer::sanitizeForSerialization($this),
@@ -503,7 +503,7 @@ class TestQueryStyleDeepObjectExplodeTrueObjectAllOfQueryObjectParameter impleme
     *
     * @return string
     */
-    public function toHeaderValue()
+    public function toHeaderValue(): string
    {
        return json_encode(ObjectSerializer::sanitizeForSerialization($this));
    }
--- a/samples/client/echo_api/php-nextgen/src/Model/TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter.php
+++ b/samples/client/echo_api/php-nextgen/src/Model/TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter.php
@@ -29,8 +29,11 @@

 namespace OpenAPI\Client\Model;

-use \ArrayAccess;
-use \OpenAPI\Client\ObjectSerializer;
+use ArrayAccess;
+use JsonSerializable;
+use InvalidArgumentException;
+use ReturnTypeWillChange;
+use OpenAPI\Client\ObjectSerializer;

 /**
 * TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter Class Doc Comment
@@ -39,9 +42,9 @@ use \OpenAPI\Client\ObjectSerializer;
 * @package  OpenAPI\Client
 * @author   OpenAPI Generator team
 * @link     https://openapi-generator.tech
- * @implements \ArrayAccess<string, mixed>
+ * @implements ArrayAccess<string, mixed>
 */
-class TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter implements ModelInterface, ArrayAccess, \JsonSerializable
+class TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter implements ModelInterface, ArrayAccess, JsonSerializable
 {
    public const DISCRIMINATOR = null;

@@ -50,32 +53,30 @@ class TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter implements Mo
      *
      * @var string
      */
-    protected static $openAPIModelName = 'test_query_style_form_explode_true_array_string_query_object_parameter';
+    protected static string $openAPIModelName = 'test_query_style_form_explode_true_array_string_query_object_parameter';

    /**
      * Array of property to type mappings. Used for (de)serialization
      *
-      * @var string[]
+      * @var array<string, string>
      */
-    protected static $openAPITypes = [
+    protected static array $openAPITypes = [
        'values' => 'string[]'
    ];

    /**
      * Array of property to format mappings. Used for (de)serialization
      *
-      * @var string[]
-      * @phpstan-var array<string, string|null>
-      * @psalm-var array<string, string|null>
+      * @var array<string, string|null>
      */
-    protected static $openAPIFormats = [
+    protected static array $openAPIFormats = [
        'values' => null
    ];

    /**
      * Array of nullable properties. Used for (de)serialization
      *
-      * @var boolean[]
+      * @var array<string, bool>
      */
    protected static array $openAPINullables = [
        'values' => false
@@ -84,16 +85,16 @@ class TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter implements Mo
    /**
      * If a nullable field gets set to null, insert it here
      *
-      * @var boolean[]
+      * @var array<string, bool>
      */
    protected array $openAPINullablesSetToNull = [];

    /**
     * Array of property to type mappings. Used for (de)serialization
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function openAPITypes()
+    public static function openAPITypes(): array
    {
        return self::$openAPITypes;
    }
@@ -101,9 +102,9 @@ class TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter implements Mo
    /**
     * Array of property to format mappings. Used for (de)serialization
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function openAPIFormats()
+    public static function openAPIFormats(): array
    {
        return self::$openAPIFormats;
    }
@@ -111,7 +112,7 @@ class TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter implements Mo
    /**
     * Array of nullable properties
     *
-     * @return array
+     * @return array<string, bool>
     */
    protected static function openAPINullables(): array
    {
@@ -121,7 +122,7 @@ class TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter implements Mo
    /**
     * Array of nullable field names deliberately set to null
     *
-     * @return boolean[]
+     * @return array<string, bool>
     */
    private function getOpenAPINullablesSetToNull(): array
    {
@@ -131,7 +132,7 @@ class TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter implements Mo
    /**
     * Setter - Array of nullable field names deliberately set to null
     *
-     * @param boolean[] $openAPINullablesSetToNull
+     * @param array<string, bool> $openAPINullablesSetToNull
     */
    private function setOpenAPINullablesSetToNull(array $openAPINullablesSetToNull): void
    {
@@ -164,27 +165,27 @@ class TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter implements Mo
     * Array of attributes where the key is the local name,
     * and the value is the original name
     *
-     * @var string[]
+     * @var array<string, string>
     */
-    protected static $attributeMap = [
+    protected static array $attributeMap = [
        'values' => 'values'
    ];

    /**
     * Array of attributes to setter functions (for deserialization of responses)
     *
-     * @var string[]
+     * @var array<string, string>
     */
-    protected static $setters = [
+    protected static array $setters = [
        'values' => 'setValues'
    ];

    /**
     * Array of attributes to getter functions (for serialization of requests)
     *
-     * @var string[]
+     * @var array<string, string>
     */
-    protected static $getters = [
+    protected static array $getters = [
        'values' => 'getValues'
    ];

@@ -192,9 +193,9 @@ class TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter implements Mo
     * Array of attributes where the key is the local name,
     * and the value is the original name
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function attributeMap()
+    public static function attributeMap(): array
    {
        return self::$attributeMap;
    }
@@ -202,9 +203,9 @@ class TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter implements Mo
    /**
     * Array of attributes to setter functions (for deserialization of responses)
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function setters()
+    public static function setters(): array
    {
        return self::$setters;
    }
@@ -212,9 +213,9 @@ class TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter implements Mo
    /**
     * Array of attributes to getter functions (for serialization of requests)
     *
-     * @return array
+     * @return array<string, string>
     */
-    public static function getters()
+    public static function getters(): array
    {
        return self::$getters;
    }
@@ -224,7 +225,7 @@ class TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter implements Mo
     *
     * @return string
     */
-    public function getModelName()
+    public function getModelName(): string
    {
        return self::$openAPIModelName;
    }
@@ -233,15 +234,14 @@ class TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter implements Mo
    /**
     * Associative array for storing property values
     *
-     * @var mixed[]
+     * @var array
     */
-    protected $container = [];
+    protected array $container = [];

    /**
     * Constructor
     *
-     * @param mixed[] $data Associated array of property values
-     *                      initializing the model
+     * @param array $data Associated array of property values initializing the model
     */
    public function __construct(array $data = null)
    {
@@ -257,7 +257,7 @@ class TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter implements Mo
    * @param array  $fields
    * @param mixed  $defaultValue
    */
-    private function setIfExists(string $variableName, array $fields, $defaultValue): void
+    private function setIfExists(string $variableName, array $fields, mixed $defaultValue): void
    {
        if (self::isNullable($variableName) && array_key_exists($variableName, $fields) && is_null($fields[$variableName])) {
            $this->openAPINullablesSetToNull[] = $variableName;
@@ -269,9 +269,9 @@ class TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter implements Mo
    /**
     * Show all the invalid properties with reasons.
     *
-     * @return array invalid properties with reasons
+     * @return string[] invalid properties with reasons
     */
-    public function listInvalidProperties()
+    public function listInvalidProperties(): array
    {
        $invalidProperties = [];

@@ -284,7 +284,7 @@ class TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter implements Mo
     *
     * @return bool True if all properties are valid
     */
-    public function valid()
+    public function valid(): bool
    {
        return count($this->listInvalidProperties()) === 0;
    }
@@ -295,7 +295,7 @@ class TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter implements Mo
     *
     * @return string[]|null
     */
-    public function getValues()
+    public function getValues(): ?array
    {
        return $this->container['values'];
    }
@@ -305,12 +305,12 @@ class TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter implements Mo
     *
     * @param string[]|null $values values
     *
-     * @return self
+     * @return $this
     */
-    public function setValues($values)
+    public function setValues(?array $values): static
    {
        if (is_null($values)) {
-            throw new \InvalidArgumentException('non-nullable values cannot be null');
+            throw new InvalidArgumentException('non-nullable values cannot be null');
        }
        $this->container['values'] = $values;

@@ -323,7 +323,7 @@ class TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter implements Mo
     *
     * @return boolean
     */
-    public function offsetExists($offset): bool
+    public function offsetExists(mixed $offset): bool
    {
        return isset($this->container[$offset]);
    }
@@ -335,8 +335,8 @@ class TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter implements Mo
     *
     * @return mixed|null
     */
-    #[\ReturnTypeWillChange]
-    public function offsetGet($offset)
+    #[ReturnTypeWillChange]
+    public function offsetGet(mixed $offset): mixed
    {
        return $this->container[$offset] ?? null;
    }
@@ -349,7 +349,7 @@ class TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter implements Mo
     *
     * @return void
     */
-    public function offsetSet($offset, $value): void
+    public function offsetSet(mixed $offset, mixed $value): void
    {
        if (is_null($offset)) {
            $this->container[] = $value;
@@ -365,7 +365,7 @@ class TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter implements Mo
     *
     * @return void
     */
-    public function offsetUnset($offset): void
+    public function offsetUnset(mixed $offset): void
    {
        unset($this->container[$offset]);
    }
@@ -377,8 +377,8 @@ class TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter implements Mo
     * @return mixed Returns data which can be serialized by json_encode(), which is a value
     * of any type other than a resource.
     */
-    #[\ReturnTypeWillChange]
-    public function jsonSerialize()
+    #[ReturnTypeWillChange]
+    public function jsonSerialize(): mixed
    {
       return ObjectSerializer::sanitizeForSerialization($this);
    }
@@ -388,7 +388,7 @@ class TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter implements Mo
     *
     * @return string
     */
-    public function __toString()
+    public function __toString(): string
    {
        return json_encode(
            ObjectSerializer::sanitizeForSerialization($this),
@@ -401,7 +401,7 @@ class TestQueryStyleFormExplodeTrueArrayStringQueryObjectParameter implements Mo
     *
     * @return string
     */
-    public function toHeaderValue()
+    public function toHeaderValue(): string
    {
        return json_encode(ObjectSerializer::sanitizeForSerialization($this));
    }