diff --git a/composer.json b/composer.json
index 20e18af..8c17699 100644
--- a/composer.json
+++ b/composer.json
@@ -13,7 +13,7 @@
     "require": {
         "php": "^7.2 || ^8.0",
         "php-stubs/wordpress-stubs": "^4.7 || ^5.0 || ^6.0",
-        "phpstan/phpstan": "^1.6",
+        "phpstan/phpstan": "^1.8.7",
         "symfony/polyfill-php73": "^1.12.0"
     },
     "require-dev": {
diff --git a/tests/data/_get_list_table.php b/tests/data/_get_list_table.php
index 2d1b45d..ee11bc3 100644
--- a/tests/data/_get_list_table.php
+++ b/tests/data/_get_list_table.php
@@ -11,4 +11,4 @@
 assertType('Unknown_Table|false', _get_list_table('Unknown_Table'));
 
 // Unknown class name
-assertType('\WP_List_Table|false', _get_list_table($_GET['foo']));
+assertType('WP_List_Table|false', _get_list_table($_GET['foo']));
diff --git a/tests/data/get_comment.php b/tests/data/get_comment.php
index ac224cb..bd314d2 100644
--- a/tests/data/get_comment.php
+++ b/tests/data/get_comment.php
@@ -12,7 +12,7 @@
 assertType('WP_Comment|null', get_comment(1, 'Hello'));
 
 // Unknown output
-assertType('array|\WP_Comment|null', get_comment(1, $_GET['foo']));
+assertType('array|WP_Comment|null', get_comment(1, $_GET['foo']));
 
 // Associative array output
 assertType('array<string, mixed>|null', get_comment(1, ARRAY_A));
diff --git a/tests/data/get_object_taxonomies.php b/tests/data/get_object_taxonomies.php
index f379057..c0ef54b 100644
--- a/tests/data/get_object_taxonomies.php
+++ b/tests/data/get_object_taxonomies.php
@@ -12,7 +12,7 @@
 assertType('array<int, string>', get_object_taxonomies('post', 'Hello'));
 
 // Unknown output
-assertType('array<string|\WP_Taxonomy>', get_object_taxonomies('post', $_GET['foo']));
+assertType('array<string|WP_Taxonomy>', get_object_taxonomies('post', $_GET['foo']));
 
 // Objects output
 assertType('array<string, WP_Taxonomy>', get_object_taxonomies('post', 'objects'));