Turn Regex classes immutable where possible

src/Type/Regex/RegexAlternation.php

@@ -10,7 +10,7 @@ final class RegexAlternation
 	/** @var array<int, list<int>> */
 	private array $groupCombinations = [];
 
-	public function __construct(private int $alternationId)
+	public function __construct(private readonly int $alternationId)
 	{
 	}
 

src/Type/Regex/RegexCapturingGroup.php

@@ -4,18 +4,18 @@
 
 use PHPStan\Type\Type;
 
-class RegexCapturingGroup
+final class RegexCapturingGroup
 {
 
 	private bool $forceNonOptional = false;
 
 	public function __construct(
-		private int $id,
-		private ?string $name,
-		private ?RegexAlternation $alternation,
-		private bool $inOptionalQuantification,
-		private RegexCapturingGroup|RegexNonCapturingGroup|null $parent,
-		private Type $type,
+		private readonly int $id,
+		private readonly ?string $name,
+		private readonly ?RegexAlternation $alternation,
+		private readonly bool $inOptionalQuantification,
+		private readonly RegexCapturingGroup|RegexNonCapturingGroup|null $parent,
+		private readonly Type $type,
 	)
 	{
 	}

src/Type/Regex/RegexNonCapturingGroup.php

@@ -2,14 +2,14 @@
 
 namespace PHPStan\Type\Regex;
 
-class RegexNonCapturingGroup
+final class RegexNonCapturingGroup
 {
 
 	public function __construct(
-		private ?RegexAlternation $alternation,
-		private bool $inOptionalQuantification,
-		private RegexCapturingGroup|RegexNonCapturingGroup|null $parent,
-		private bool $resetGroupCounter,
+		private readonly ?RegexAlternation $alternation,
+		private readonly bool $inOptionalQuantification,
+		private readonly RegexCapturingGroup|RegexNonCapturingGroup|null $parent,
+		private readonly bool $resetGroupCounter,
 	)
 	{
 	}