diff --git a/src/ErrorInformationRenderer.php b/src/ErrorInformationRenderer.php
index e0fab0b..18ae6b8 100644
--- a/src/ErrorInformationRenderer.php
+++ b/src/ErrorInformationRenderer.php
@@ -36,13 +36,11 @@ class ErrorInformationRenderer
 
     private string $highlightChar = self::DEFAULT_HIGHLIGHT_CHAR;
 
-    private TokenInterface $token;
-
-    public function __construct(ReadableInterface $source, TokenInterface $token)
-    {
-        $this->token = $token;
-
-        $this->position = Position::fromOffset($source, $token->getOffset());
+    public function __construct(
+        ReadableInterface $source,
+        private readonly TokenInterface $token,
+    ) {
+        $this->position = Position::fromOffset($source, $this->token->getOffset());
 
         $this->reader = new LineReader($source);
     }
diff --git a/src/RuntimeException.php b/src/RuntimeException.php
index f22d7a8..2bffed5 100644
--- a/src/RuntimeException.php
+++ b/src/RuntimeException.php
@@ -18,13 +18,12 @@ abstract class RuntimeException extends \RuntimeException implements RuntimeExce
 
     private ?ReadableInterface $source = null;
 
-    private string $original;
-
-    public function __construct(string $message = '', int $code = 0, ?\Throwable $previous = null)
-    {
-        $this->original = $message;
-
-        parent::__construct($message, $code, $previous);
+    public function __construct(
+        private readonly string $original = '',
+        int $code = 0,
+        ?\Throwable $previous = null,
+    ) {
+        parent::__construct($this->original, $code, $previous);
     }
 
     public function getOriginalMessage(): string
diff --git a/src/UndefinedToken.php b/src/UndefinedToken.php
index 7b244a8..7577be9 100644
--- a/src/UndefinedToken.php
+++ b/src/UndefinedToken.php
@@ -6,22 +6,20 @@
 
 use Phplrt\Contracts\Lexer\TokenInterface;
 use Phplrt\Contracts\Position\PositionInterface;
+use Phplrt\Lexer\Token\EndOfInput;
 
 /**
  * @internal This class can be used for internal representation of exceptions
  */
 final class UndefinedToken implements TokenInterface
 {
-    private PositionInterface $position;
-
-    public function __construct(PositionInterface $position)
-    {
-        $this->position = $position;
-    }
+    public function __construct(
+        private readonly PositionInterface $position,
+    ) {}
 
     public function getName(): string
     {
-        return TokenInterface::END_OF_INPUT;
+        return EndOfInput::DEFAULT_TOKEN_NAME;
     }
 
     public function getOffset(): int
diff --git a/tests/Unit/UndefinedTokenTest.php b/tests/Unit/UndefinedTokenTest.php
index dcb1efa..eb49fbc 100644
--- a/tests/Unit/UndefinedTokenTest.php
+++ b/tests/Unit/UndefinedTokenTest.php
@@ -6,6 +6,7 @@
 
 use Phplrt\Contracts\Lexer\TokenInterface;
 use Phplrt\Exception\UndefinedToken;
+use Phplrt\Lexer\Token\EndOfInput;
 use Phplrt\Position\Position;
 
 class UndefinedTokenTest extends TestCase
@@ -19,7 +20,7 @@ public function testName(): void
     {
         $token = $this->create();
 
-        $this->assertSame(TokenInterface::END_OF_INPUT, $token->getName());
+        $this->assertSame(EndOfInput::DEFAULT_TOKEN_NAME, $token->getName());
     }
 
     public function testOffset(): void