diff --git a/composer.json b/composer.json
index 0e962b5c..3347466c 100644
--- a/composer.json
+++ b/composer.json
@@ -51,6 +51,7 @@
     },
     "require-dev": {
         "pestphp/pest-dev-tools": "^2.0.0",
+        "rector/rector": "^0.15.0",
         "symfony/process": "^6.2.0"
     },
     "minimum-stability": "dev",
@@ -66,7 +67,9 @@
         "bin/pest"
     ],
     "scripts": {
+        "refacto": "rector",
         "lint": "pint",
+        "test:refactor": "rector --dry-run",
         "test:lint": "pint --test",
         "test:types": "phpstan analyse --ansi --memory-limit=-1 --debug",
         "test:unit": "php bin/pest --colors=always --exclude-group=integration --compact",
@@ -75,6 +78,7 @@
         "test:integration": "php bin/pest --colors=always --group=integration -v",
         "update:snapshots": "REBUILD_SNAPSHOTS=true php bin/pest --colors=always",
         "test": [
+            "@rest:refacto",
             "@test:lint",
             "@test:types",
             "@test:unit",
diff --git a/rector.php b/rector.php
new file mode 100644
index 00000000..589b8cd0
--- /dev/null
+++ b/rector.php
@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+use Rector\CodeQuality\Rector\Class_\InlineConstructorDefaultToPropertyRector;
+use Rector\Config\RectorConfig;
+use Rector\Set\ValueObject\LevelSetList;
+use Rector\Set\ValueObject\SetList;
+
+return static function (RectorConfig $rectorConfig): void {
+    $rectorConfig->paths([
+        __DIR__.'/src',
+    ]);
+
+    $rectorConfig->rules([
+        InlineConstructorDefaultToPropertyRector::class,
+    ]);
+
+    $rectorConfig->sets([
+        LevelSetList::UP_TO_PHP_81,
+        SetList::CODE_QUALITY,
+        SetList::DEAD_CODE,
+        SetList::EARLY_RETURN,
+        SetList::TYPE_DECLARATION,
+        SetList::PRIVATIZATION,
+    ]);
+};
diff --git a/src/Bootstrappers/BootExceptionHandler.php b/src/Bootstrappers/BootExceptionHandler.php
index a504ee7e..99119f41 100644
--- a/src/Bootstrappers/BootExceptionHandler.php
+++ b/src/Bootstrappers/BootExceptionHandler.php
@@ -5,16 +5,17 @@ declare(strict_types=1);
 namespace Pest\Bootstrappers;
 
 use NunoMaduro\Collision;
+use Pest\Contracts\Bootstrapper;
 
 /**
  * @internal
  */
-final class BootExceptionHandler
+final class BootExceptionHandler implements Bootstrapper
 {
     /**
      * Boots the Exception Handler.
      */
-    public function __invoke(): void
+    public function boot(): void
     {
         $handler = new Collision\Provider();
 
diff --git a/src/Bootstrappers/BootFiles.php b/src/Bootstrappers/BootFiles.php
index 7629e7ed..44235b80 100644
--- a/src/Bootstrappers/BootFiles.php
+++ b/src/Bootstrappers/BootFiles.php
@@ -4,6 +4,7 @@ declare(strict_types=1);
 
 namespace Pest\Bootstrappers;
 
+use Pest\Contracts\Bootstrapper;
 use Pest\Support\DatasetInfo;
 use Pest\Support\Str;
 use function Pest\testDirectory;
@@ -15,7 +16,7 @@ use SebastianBergmann\FileIterator\Facade as PhpUnitFileIterator;
 /**
  * @internal
  */
-final class BootFiles
+final class BootFiles implements Bootstrapper
 {
     /**
      * The Pest convention.
@@ -33,7 +34,7 @@ final class BootFiles
     /**
      * Boots the Subscribers.
      */
-    public function __invoke(): void
+    public function boot(): void
     {
         $rootPath = TestSuite::getInstance()->rootPath;
         $testsPath = $rootPath.DIRECTORY_SEPARATOR.testDirectory();
diff --git a/src/Bootstrappers/BootSubscribers.php b/src/Bootstrappers/BootSubscribers.php
index 815c7821..e9819fa4 100644
--- a/src/Bootstrappers/BootSubscribers.php
+++ b/src/Bootstrappers/BootSubscribers.php
@@ -4,6 +4,7 @@ declare(strict_types=1);
 
 namespace Pest\Bootstrappers;
 
+use Pest\Contracts\Bootstrapper;
 use Pest\Subscribers;
 use PHPUnit\Event;
 use PHPUnit\Event\Subscriber;
@@ -11,7 +12,7 @@ use PHPUnit\Event\Subscriber;
 /**
  * @internal
  */
-final class BootSubscribers
+final class BootSubscribers implements Bootstrapper
 {
     /**
      * The Kernel subscribers.
@@ -28,7 +29,7 @@ final class BootSubscribers
     /**
      * Boots the Subscribers.
      */
-    public function __invoke(): void
+    public function boot(): void
     {
         foreach (self::SUBSCRIBERS as $subscriber) {
             Event\Facade::registerSubscriber(
diff --git a/src/Bootstrappers/BootView.php b/src/Bootstrappers/BootView.php
index 226b7982..2ae4c509 100644
--- a/src/Bootstrappers/BootView.php
+++ b/src/Bootstrappers/BootView.php
@@ -4,13 +4,14 @@ declare(strict_types=1);
 
 namespace Pest\Bootstrappers;
 
+use Pest\Contracts\Bootstrapper;
 use Pest\Support\View;
 use Symfony\Component\Console\Output\OutputInterface;
 
 /**
  * @internal
  */
-final class BootView
+final class BootView implements Bootstrapper
 {
     public function __construct(
         private readonly OutputInterface $output
@@ -21,7 +22,7 @@ final class BootView
     /**
      * Boots the view renderer.
      */
-    public function __invoke(): void
+    public function boot(): void
     {
         View::renderUsing($this->output);
     }
diff --git a/src/Concerns/Pipeable.php b/src/Concerns/Pipeable.php
index 0a29d6a1..c23427cd 100644
--- a/src/Concerns/Pipeable.php
+++ b/src/Concerns/Pipeable.php
@@ -58,6 +58,6 @@ trait Pipeable
      */
     private function pipes(string $name, object $context, string $scope): array
     {
-        return array_map(fn (Closure $pipe) => $pipe->bindTo($context, $scope), self::$pipes[$name] ?? []);
+        return array_map(fn (Closure $pipe): \Closure => $pipe->bindTo($context, $scope), self::$pipes[$name] ?? []);
     }
 }
diff --git a/src/Concerns/Testable.php b/src/Concerns/Testable.php
index 36d47e38..f7075c28 100644
--- a/src/Concerns/Testable.php
+++ b/src/Concerns/Testable.php
@@ -259,7 +259,7 @@ trait Testable
      */
     private function __callClosure(Closure $closure, array $arguments): mixed
     {
-        return ExceptionTrace::ensure(fn () => call_user_func_array(Closure::bind($closure, $this, $this::class), $arguments));
+        return ExceptionTrace::ensure(fn (): mixed => call_user_func_array(Closure::bind($closure, $this, $this::class), $arguments));
     }
 
     /**
diff --git a/src/Contracts/Bootstrapper.php b/src/Contracts/Bootstrapper.php
new file mode 100644
index 00000000..520aede1
--- /dev/null
+++ b/src/Contracts/Bootstrapper.php
@@ -0,0 +1,16 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Pest\Contracts;
+
+/**
+ * @internal
+ */
+interface Bootstrapper
+{
+    /**
+     * Boots the bootstrapper.
+     */
+    public function boot(): void;
+}
diff --git a/src/Exceptions/InvalidExpectationValue.php b/src/Exceptions/InvalidExpectationValue.php
index 68a15c64..7a223f8c 100644
--- a/src/Exceptions/InvalidExpectationValue.php
+++ b/src/Exceptions/InvalidExpectationValue.php
@@ -12,11 +12,9 @@ use InvalidArgumentException;
 final class InvalidExpectationValue extends InvalidArgumentException
 {
     /**
-     * @return never
-     *
      * @throws self
      */
-    public static function expected(string $type): void
+    public static function expected(string $type): never
     {
         throw new self(sprintf('Invalid expectation value type. Expected [%s].', $type));
     }
diff --git a/src/Expectation.php b/src/Expectation.php
index 59d5f573..2da24e75 100644
--- a/src/Expectation.php
+++ b/src/Expectation.php
@@ -70,10 +70,12 @@ final class Expectation
             InvalidExpectationValue::expected('string');
         }
 
-        /** @var array<int|string, mixed>|bool $value */
-        $value = json_decode($this->value, true, 512);
+        $this->toBeJson();
 
-        return $this->toBeJson()->and($value);
+        /** @var array<int|string, mixed>|bool $value */
+        $value = json_decode($this->value, true, 512, JSON_THROW_ON_ERROR);
+
+        return $this->and($value);
     }
 
     /**
diff --git a/src/Expectations/OppositeExpectation.php b/src/Expectations/OppositeExpectation.php
index beed91a8..9a8fefbe 100644
--- a/src/Expectations/OppositeExpectation.php
+++ b/src/Expectations/OppositeExpectation.php
@@ -90,9 +90,8 @@ final class OppositeExpectation
      * Creates a new expectation failed exception with a nice readable message.
      *
      * @param  array<int, mixed>  $arguments
-     * @return never
      */
-    private function throwExpectationFailedException(string $name, array $arguments = []): void
+    private function throwExpectationFailedException(string $name, array $arguments = []): never
     {
         $exporter = new Exporter();
 
diff --git a/src/Factories/TestCaseFactory.php b/src/Factories/TestCaseFactory.php
index 4591d9f1..e1b4ea3a 100644
--- a/src/Factories/TestCaseFactory.php
+++ b/src/Factories/TestCaseFactory.php
@@ -85,7 +85,7 @@ final class TestCaseFactory
 
         $methods = array_values(array_filter(
             $this->methods,
-            fn ($method) => $methodsUsingOnly === [] || in_array($method, $methodsUsingOnly, true)
+            fn ($method): bool => $methodsUsingOnly === [] || in_array($method, $methodsUsingOnly, true)
         ));
 
         if ($methods !== []) {
@@ -165,21 +165,21 @@ final class TestCaseFactory
             $classFQN .= $className;
         }
 
-        $classAvailableAttributes = array_filter(self::ATTRIBUTES, fn (string $attribute) => $attribute::ABOVE_CLASS);
-        $methodAvailableAttributes = array_filter(self::ATTRIBUTES, fn (string $attribute) => ! $attribute::ABOVE_CLASS);
+        $classAvailableAttributes = array_filter(self::ATTRIBUTES, fn (string $attribute): bool => $attribute::ABOVE_CLASS);
+        $methodAvailableAttributes = array_filter(self::ATTRIBUTES, fn (string $attribute): bool => ! $attribute::ABOVE_CLASS);
 
         $classAttributes = [];
 
         foreach ($classAvailableAttributes as $attribute) {
             $classAttributes = array_reduce(
                 $methods,
-                fn (array $carry, TestCaseMethodFactory $methodFactory) => (new $attribute())->__invoke($methodFactory, $carry),
+                fn (array $carry, TestCaseMethodFactory $methodFactory): array => (new $attribute())->__invoke($methodFactory, $carry),
                 $classAttributes
             );
         }
 
         $methodsCode = implode('', array_map(
-            fn (TestCaseMethodFactory $methodFactory) => $methodFactory->buildForEvaluation(
+            fn (TestCaseMethodFactory $methodFactory): string => $methodFactory->buildForEvaluation(
                 $classFQN,
                 self::ANNOTATIONS,
                 $methodAvailableAttributes
@@ -188,7 +188,7 @@ final class TestCaseFactory
         ));
 
         $classAttributesCode = implode('', array_map(
-            static fn (string $attribute) => sprintf("\n%s", $attribute),
+            static fn (string $attribute): string => sprintf("\n%s", $attribute),
             array_unique($classAttributes),
         ));
 
diff --git a/src/Factories/TestCaseMethodFactory.php b/src/Factories/TestCaseMethodFactory.php
index 09cf51e2..59b6c6c7 100644
--- a/src/Factories/TestCaseMethodFactory.php
+++ b/src/Factories/TestCaseMethodFactory.php
@@ -97,7 +97,7 @@ final class TestCaseMethodFactory
             $testCase->chains->chain($this);
             $method->chains->chain($this);
 
-            return \Pest\Support\Closure::bind($closure, $this, $this::class)(...func_get_args());
+            return \Pest\Support\Closure::bind($closure, $this, self::class)(...func_get_args());
         };
     }
 
@@ -147,11 +147,11 @@ final class TestCaseMethodFactory
         }
 
         $annotations = implode('', array_map(
-            static fn ($annotation) => sprintf("\n     * %s", $annotation), $annotations,
+            static fn ($annotation): string => sprintf("\n     * %s", $annotation), $annotations,
         ));
 
         $attributes = implode('', array_map(
-            static fn ($attribute) => sprintf("\n        %s", $attribute), $attributes,
+            static fn ($attribute): string => sprintf("\n        %s", $attribute), $attributes,
         ));
 
         return <<<PHP
diff --git a/src/Functions.php b/src/Functions.php
index ea53c22c..8d033694 100644
--- a/src/Functions.php
+++ b/src/Functions.php
@@ -89,7 +89,7 @@ if (! function_exists('test')) {
      *
      * @return TestCall|TestCase|mixed
      */
-    function test(string $description = null, Closure $closure = null)
+    function test(string $description = null, Closure $closure = null): HigherOrderTapProxy|TestCall
     {
         if ($description === null && TestSuite::getInstance()->test !== null) {
             return new HigherOrderTapProxy(TestSuite::getInstance()->test);
diff --git a/src/Kernel.php b/src/Kernel.php
index 76ab91f1..bf7b200f 100644
--- a/src/Kernel.php
+++ b/src/Kernel.php
@@ -4,6 +4,7 @@ declare(strict_types=1);
 
 namespace Pest;
 
+use Pest\Contracts\Bootstrapper;
 use Pest\Plugins\Actions\CallsAddsOutput;
 use Pest\Plugins\Actions\CallsBoot;
 use Pest\Plugins\Actions\CallsShutdown;
@@ -49,7 +50,10 @@ final class Kernel
     public static function boot(): self
     {
         foreach (self::BOOTSTRAPPERS as $bootstrapper) {
-            Container::getInstance()->get($bootstrapper)->__invoke();
+            $bootstrapper = Container::getInstance()->get($bootstrapper);
+            assert($bootstrapper instanceof Bootstrapper);
+
+            $bootstrapper->boot();
         }
 
         (new CallsBoot())->__invoke();
diff --git a/src/PendingCalls/TestCall.php b/src/PendingCalls/TestCall.php
index 215b4de8..d24c593b 100644
--- a/src/PendingCalls/TestCall.php
+++ b/src/PendingCalls/TestCall.php
@@ -154,7 +154,7 @@ final class TestCall
 
         $condition = is_callable($condition)
             ? $condition
-            : fn () => $condition;
+            : fn (): bool => $condition;
 
         $message = is_string($conditionOrMessage)
             ? $conditionOrMessage
diff --git a/src/Repositories/DatasetsRepository.php b/src/Repositories/DatasetsRepository.php
index 3c3f5fc1..83eddac2 100644
--- a/src/Repositories/DatasetsRepository.php
+++ b/src/Repositories/DatasetsRepository.php
@@ -90,8 +90,7 @@ final class DatasetsRepository
      */
     public static function resolve(array $dataset, string $currentTestFile): array|null
     {
-        /* @phpstan-ignore-next-line */
-        if (empty($dataset)) {
+        if ($dataset === []) {
             return null;
         }
 
@@ -177,25 +176,21 @@ final class DatasetsRepository
     /**
      * @return Closure|iterable<int|string, mixed>
      */
-    private static function getScopedDataset(string $name, string $currentTestFile)
+    private static function getScopedDataset(string $name, string $currentTestFile): Closure|iterable
     {
-        $matchingDatasets = array_filter(self::$datasets, function (string $key) use ($name, $currentTestFile) {
+        $matchingDatasets = array_filter(self::$datasets, function (string $key) use ($name, $currentTestFile): bool {
             [$datasetScope, $datasetName] = explode(self::SEPARATOR, $key);
 
             if ($name !== $datasetName) {
                 return false;
             }
 
-            if (! str_starts_with($currentTestFile, $datasetScope)) {
-                return false;
-            }
-
-            return true;
+            return str_starts_with($currentTestFile, $datasetScope);
         }, ARRAY_FILTER_USE_KEY);
 
         $closestScopeDatasetKey = array_reduce(
             array_keys($matchingDatasets),
-            fn ($keyA, $keyB) => $keyA !== null && strlen($keyA) > strlen($keyB) ? $keyA : $keyB
+            fn ($keyA, $keyB) => $keyA !== null && strlen((string) $keyA) > strlen($keyB) ? $keyA : $keyB
         );
 
         if ($closestScopeDatasetKey === null) {
diff --git a/src/Repositories/TestRepository.php b/src/Repositories/TestRepository.php
index ff302cf7..acf163b9 100644
--- a/src/Repositories/TestRepository.php
+++ b/src/Repositories/TestRepository.php
@@ -42,7 +42,7 @@ final class TestRepository
      */
     public function getFilenames(): array
     {
-        $testCases = array_filter($this->testCases, static fn (TestCaseFactory $testCase) => $testCase->methodsUsingOnly() !== []);
+        $testCases = array_filter($this->testCases, static fn (TestCaseFactory $testCase): bool => $testCase->methodsUsingOnly() !== []);
 
         if ($testCases === []) {
             $testCases = $this->testCases;
diff --git a/src/Support/ChainableClosure.php b/src/Support/ChainableClosure.php
index 3c228872..55dcca3a 100644
--- a/src/Support/ChainableClosure.php
+++ b/src/Support/ChainableClosure.php
@@ -22,8 +22,8 @@ final class ChainableClosure
                 throw ShouldNotHappen::fromMessage('$this not bound to chainable closure.');
             }
 
-            \Pest\Support\Closure::bind($closure, $this, $this::class)(...func_get_args());
-            \Pest\Support\Closure::bind($next, $this, $this::class)(...func_get_args());
+            \Pest\Support\Closure::bind($closure, $this, self::class)(...func_get_args());
+            \Pest\Support\Closure::bind($next, $this, self::class)(...func_get_args());
         };
     }
 
diff --git a/src/Support/Container.php b/src/Support/Container.php
index 8f865ce9..3afa9818 100644
--- a/src/Support/Container.php
+++ b/src/Support/Container.php
@@ -16,7 +16,7 @@ final class Container
     private static ?Container $instance = null;
 
     /**
-     * @var array<string, mixed>
+     * @var array<string, object|string>
      */
     private array $instances = [];
 
@@ -25,37 +25,30 @@ final class Container
      */
     public static function getInstance(): self
     {
-        if (static::$instance === null) {
-            static::$instance = new self();
+        if (self::$instance === null) {
+            self::$instance = new self();
         }
 
-        return static::$instance;
+        return self::$instance;
     }
 
     /**
      * Gets a dependency from the container.
-     *
-     * @template TObject of object
-     *
-     * @param  class-string<TObject>  $id
-     * @return TObject
      */
-    public function get(string $id): mixed
+    public function get(string $id): object|string
     {
         if (! array_key_exists($id, $this->instances)) {
+            /** @var class-string $id */
             $this->instances[$id] = $this->build($id);
         }
 
-        /** @var TObject $concrete */
-        $concrete = $this->instances[$id];
-
-        return $concrete;
+        return $this->instances[$id];
     }
 
     /**
      * Adds the given instance to the container.
      */
-    public function add(string $id, mixed $instance): void
+    public function add(string $id, object|string $instance): void
     {
         $this->instances[$id] = $instance;
     }
@@ -68,7 +61,7 @@ final class Container
      * @param  class-string<TObject>  $id
      * @return TObject
      */
-    private function build(string $id): mixed
+    private function build(string $id): object
     {
         $reflectionClass = new ReflectionClass($id);
 
@@ -77,7 +70,7 @@ final class Container
 
             if ($constructor !== null) {
                 $params = array_map(
-                    function (ReflectionParameter $param) use ($id) {
+                    function (ReflectionParameter $param) use ($id): object|string {
                         $candidate = Reflection::getParameterClassName($param);
 
                         if ($candidate === null) {
@@ -90,7 +83,6 @@ final class Container
                             }
                         }
 
-                        // @phpstan-ignore-next-line
                         return $this->get($candidate);
                     },
                     $constructor->getParameters()
diff --git a/src/Support/Coverage.php b/src/Support/Coverage.php
index 743c73ab..c0e78e67 100644
--- a/src/Support/Coverage.php
+++ b/src/Support/Coverage.php
@@ -42,15 +42,15 @@ final class Coverage
             return false;
         }
 
-        if ($runtime->hasXdebug()) {
-            if (version_compare((string) phpversion('xdebug'), '3.1', '>=')) {
-                if (! in_array('coverage', xdebug_info('mode'), true)) {
-                    return false;
-                }
-            }
+        if (! $runtime->hasXdebug()) {
+            return true;
         }
 
-        return true;
+        if (! version_compare((string) phpversion('xdebug'), '3.1', '>=')) {
+            return true;
+        }
+
+        return in_array('coverage', xdebug_info('mode'), true);
     }
 
     /**