use readonly properties (#9)

src/Base/CompareTrait.php

@@ -12,7 +12,7 @@
  */
 trait CompareTrait
 {
-    private \DateTimeImmutable $dateTime;
+    private readonly \DateTimeImmutable $dateTime;
 
     /** @psalm-pure */
     public static function min(self $object, self ...$objects): self

src/Base/DateTrait.php

@@ -14,7 +14,7 @@
  */
 trait DateTrait
 {
-    private \DateTimeImmutable $dateTime;
+    private readonly \DateTimeImmutable $dateTime;
 
     abstract private function __construct(\DateTimeImmutable $dateTime);
 

src/Base/EnumTrait.php

@@ -13,7 +13,7 @@
  */
 trait EnumTrait
 {
-    private int $index;
+    private readonly int $index;
 
     private function __construct(int $index)
     {

src/Base/FormatTrait.php

@@ -10,7 +10,7 @@
  */
 trait FormatTrait
 {
-    private \DateTimeImmutable $dateTime;
+    private readonly \DateTimeImmutable $dateTime;
 
     public function __toString(): string
     {

src/Base/ModifyTrait.php

@@ -12,7 +12,7 @@
  */
 trait ModifyTrait
 {
-    private \DateTimeImmutable $dateTime;
+    private readonly \DateTimeImmutable $dateTime;
 
     public function modify(string $modify): self
     {

src/Base/TimeTrait.php

@@ -12,7 +12,7 @@
  */
 trait TimeTrait
 {
-    private \DateTimeImmutable $dateTime;
+    private readonly \DateTimeImmutable $dateTime;
 
     public function getHour(): int
     {

src/Date.php

@@ -21,7 +21,7 @@ final class Date implements \JsonSerializable, \Stringable
     use Base\FormatTrait;
     use Base\ModifyTrait;
 
-    private \DateTimeImmutable $dateTime;
+    private readonly \DateTimeImmutable $dateTime;
 
     private function __construct(\DateTimeImmutable $dateTime)
     {

src/DateTime.php

@@ -22,8 +22,8 @@ final class DateTime implements \JsonSerializable, \Stringable
     use Base\ModifyTrait;
     use Base\TimeTrait;
 
-    private \DateTimeImmutable $dateTime;
-    private TimeZone $timeZone;
+    private readonly \DateTimeImmutable $dateTime;
+    private readonly TimeZone $timeZone;
 
     private function __construct(\DateTimeImmutable $dateTime, ?TimeZone $timeZone = null)
     {

src/Duration.php

@@ -12,7 +12,7 @@
  */
 final class Duration implements \JsonSerializable, \Stringable
 {
-    private \DateInterval $interval;
+    private readonly \DateInterval $interval;
 
     private function __construct(\DateInterval $interval)
     {

src/Time.php

@@ -23,7 +23,7 @@ final class Time implements \JsonSerializable, \Stringable
 
     private const DATE = '1970-01-01';
 
-    private \DateTimeImmutable $dateTime;
+    private readonly \DateTimeImmutable $dateTime;
 
     private function __construct(\DateTimeImmutable $dateTime)
     {

src/TimeZone.php

@@ -11,7 +11,7 @@
  */
 final class TimeZone implements \JsonSerializable, \Stringable
 {
-    private \DateTimeZone $timeZone;
+    private readonly \DateTimeZone $timeZone;
 
     private function __construct(\DateTimeZone $timeZone)
     {