diff --git a/src/AuthorizationService.php b/src/AuthorizationService.php
index ef4c01eb..b6a11c90 100644
--- a/src/AuthorizationService.php
+++ b/src/AuthorizationService.php
@@ -22,6 +22,7 @@
 use Authorization\Policy\ResolverInterface;
 use Authorization\Policy\Result;
 use Authorization\Policy\ResultInterface;
+use Closure;
 
 class AuthorizationService implements AuthorizationServiceInterface
 {
@@ -84,33 +85,22 @@ protected function performCheck(?IdentityInterface $user, string $action, mixed
             $result = $policy->before($user, $resource, $action);
 
             if ($result !== null) {
-                return $this->resultTypeCheck($result);
+                return $result;
             }
         }
 
         $handler = $this->getCanHandler($policy, $action);
         $result = $handler($user, $resource);
 
-        return $this->resultTypeCheck($result);
-    }
-
-    /**
-     * Check result type.
-     *
-     * @param mixed $result Result from policy class instance.
-     * @return \Authorization\Policy\ResultInterface|bool
-     * @throws \Authorization\Exception\Exception If $result argument is not a boolean or ResultInterface instance.
-     */
-    protected function resultTypeCheck(mixed $result): ResultInterface|bool
-    {
-        if (is_bool($result) || $result instanceof ResultInterface) {
-            return $result;
-        }
+        assert(
+            is_bool($result) || $result instanceof ResultInterface,
+            new Exception(sprintf(
+                'Authorization check method must return `%s` or `bool`.',
+                ResultInterface::class
+            ))
+        );
 
-        throw new Exception(sprintf(
-            'Pre-authorization check must return `%s`, `bool` or `null`.',
-            ResultInterface::class
-        ));
+        return $result;
     }
 
     /**
@@ -130,18 +120,19 @@ public function applyScope(?IdentityInterface $user, string $action, $resource):
      *
      * @param mixed $policy Policy object.
      * @param string $action Action name.
-     * @return callable
+     * @return \Closure
      * @throws \Authorization\Policy\Exception\MissingMethodException
      */
-    protected function getCanHandler(mixed $policy, string $action): callable
+    protected function getCanHandler(mixed $policy, string $action): Closure
     {
         $method = 'can' . ucfirst($action);
 
-        if (!method_exists($policy, $method) && !method_exists($policy, '__call')) {
-            throw new MissingMethodException([$method, $action, get_class($policy)]);
-        }
+        assert(
+            method_exists($policy, $method) || method_exists($policy, '__call'),
+            new MissingMethodException([$method, $action, get_class($policy)])
+        );
 
-        return [$policy, $method];
+        return [$policy, $method](...);
     }
 
     /**
@@ -149,18 +140,19 @@ protected function getCanHandler(mixed $policy, string $action): callable
      *
      * @param mixed $policy Policy object.
      * @param string $action Action name.
-     * @return callable
+     * @return \Closure
      * @throws \Authorization\Policy\Exception\MissingMethodException
      */
-    protected function getScopeHandler(mixed $policy, string $action): callable
+    protected function getScopeHandler(mixed $policy, string $action): Closure
     {
         $method = 'scope' . ucfirst($action);
 
-        if (!method_exists($policy, $method)) {
-            throw new MissingMethodException([$method, $action, get_class($policy)]);
-        }
+        assert(
+            method_exists($policy, $method) || method_exists($policy, '__call'),
+            new MissingMethodException([$method, $action, get_class($policy)])
+        );
 
-        return [$policy, $method];
+        return [$policy, $method](...);
     }
 
     /**
diff --git a/src/Middleware/AuthorizationMiddleware.php b/src/Middleware/AuthorizationMiddleware.php
index d309d01c..337a050b 100644
--- a/src/Middleware/AuthorizationMiddleware.php
+++ b/src/Middleware/AuthorizationMiddleware.php
@@ -179,7 +179,7 @@ protected function buildIdentity(
         if (!$identity instanceof IdentityInterface) {
             throw new RuntimeException(sprintf(
                 'Invalid identity returned by decorator. `%s` does not implement `%s`.',
-                is_object($identity) ? get_class($identity) : gettype($identity),
+                get_debug_type($identity),
                 IdentityInterface::class
             ));
         }