diff --git a/src/InvalidDeserializedData.php b/src/InvalidDeserializedData.php
index a661d4f0..0ec0a0bb 100644
--- a/src/InvalidDeserializedData.php
+++ b/src/InvalidDeserializedData.php
@@ -4,7 +4,7 @@
 
 namespace Lendable\Json;
 
-class InvalidDeserializedData extends \RuntimeException implements Failure
+final class InvalidDeserializedData extends \RuntimeException implements Failure
 {
     public function __construct(string $unexpectedType)
     {
diff --git a/src/Serializer.php b/src/Serializer.php
index 8adb83d5..8c9a1883 100644
--- a/src/Serializer.php
+++ b/src/Serializer.php
@@ -7,7 +7,7 @@
 final readonly class Serializer
 {
     /**
-     * @phpstan-param array<mixed> $data
+     * @param array<mixed> $data
      *
      * @throws SerializationFailed
      */
@@ -26,7 +26,7 @@ public function serialize(array $data): string
      * @throws DeserializationFailed
      * @throws InvalidDeserializedData
      *
-     * @phpstan-return array<mixed>
+     * @return array<mixed>
      */
     public function deserialize(string $json): array
     {
@@ -37,7 +37,7 @@ public function deserialize(string $json): array
         }
 
         if (!\is_array($data)) {
-            throw new InvalidDeserializedData(\gettype($data));
+            throw new InvalidDeserializedData(\get_debug_type($data));
         }
 
         return $data;
diff --git a/tests/unit/SerializerTest.php b/tests/unit/SerializerTest.php
index 423b3c46..42dfc9c1 100644
--- a/tests/unit/SerializerTest.php
+++ b/tests/unit/SerializerTest.php
@@ -138,11 +138,11 @@ public function it_throws_when_deserializing_if_the_result_is_not_an_array(strin
      */
     public static function provideNonArrayRoots(): iterable
     {
-        yield 'true' => ['true', 'boolean'];
-        yield 'false' => ['false', 'boolean'];
-        yield 'null' => ['null', 'NULL'];
-        yield 'integer' => ['5', 'integer'];
-        yield 'float' => ['1.5', 'double'];
+        yield 'true' => ['true', 'bool'];
+        yield 'false' => ['false', 'bool'];
+        yield 'null' => ['null', 'null'];
+        yield 'integer' => ['5', 'int'];
+        yield 'float' => ['1.5', 'float'];
         yield 'string' => ['"foo"', 'string'];
     }