diff --git a/composer.json b/composer.json
index 5839a98..fb8ebe8 100644
--- a/composer.json
+++ b/composer.json
@@ -14,7 +14,7 @@
         "nikic/php-parser": "^4.13",
         "php-stubs/generator": "^0.8.3",
         "phpdocumentor/reflection-docblock": "^5.4.1",
-        "phpstan/phpstan": "^1.10.49",
+        "phpstan/phpstan": "^1.11",
         "phpunit/phpunit": "^9.5",
         "szepeviktor/phpcs-psr-12-neutron-hybrid-ruleset": "^1.1.1",
         "wp-coding-standards/wpcs": "3.1.0 as 2.3.0"
diff --git a/functionMap.php b/functionMap.php
index 69e0b24..35ed641 100644
--- a/functionMap.php
+++ b/functionMap.php
@@ -36,7 +36,7 @@
     '__return_empty_string' => ["''"],
     '__return_zero' => ['0'],
     '_wp_json_sanity_check' => ['T', '@phpstan-template' => 'T', 'value' => 'T', 'depth' => 'int<1, max>'],
-    '_get_list_table' => ["(\$class_name is 'WP_Posts_List_Table'|'WP_Media_List_Table'|'WP_Terms_List_Table'|'WP_Users_List_Table'|'WP_Comments_List_Table'|'WP_Post_Comments_List_Table'|'WP_Links_List_Table'|'WP_Plugin_Install_List_Table'|'WP_Themes_List_Table'|'WP_Theme_Install_List_Table'|'WP_Plugins_List_Table'|'WP_Application_Passwords_List_Table'|'WP_MS_Sites_List_Table'|'WP_MS_Users_List_Table'|'WP_MS_Themes_List_Table'|'WP_Privacy_Data_Export_Requests_List_Table'|'WP_Privacy_Data_Removal_Requests_List_Table' ? T : false)", '@phpstan-template' => 'T', 'class_name' => 'class-string<T>', 'args' => 'array{screen?: string}'],
+    '_get_list_table' => ["(\$class_name is 'WP_Posts_List_Table'|'WP_Media_List_Table'|'WP_Terms_List_Table'|'WP_Users_List_Table'|'WP_Comments_List_Table'|'WP_Post_Comments_List_Table'|'WP_Links_List_Table'|'WP_Plugin_Install_List_Table'|'WP_Themes_List_Table'|'WP_Theme_Install_List_Table'|'WP_Plugins_List_Table'|'WP_Application_Passwords_List_Table'|'WP_MS_Sites_List_Table'|'WP_MS_Users_List_Table'|'WP_MS_Themes_List_Table'|'WP_Privacy_Data_Export_Requests_List_Table'|'WP_Privacy_Data_Removal_Requests_List_Table' ? new<T> : false)", '@phpstan-template T' => 'of string', 'class_name' => 'T', 'args' => 'array{screen?: string}'],
     'absint' => ['($maybeint is T&int<0, max> ? T : ($maybeint is int<min, -1> ? int<1, max> : ($maybeint is empty ? 0 : ($maybeint is numeric-string ? int<0, max> : ($maybeint is string ? 0 : ($maybeint is true|non-empty-array ? 1 : ($maybeint is bool ? 0|1 : int<0, max>)))))))', '@phpstan-template T' => 'of int', 'maybeint' => 'T|scalar|array|resource|null'],
     'addslashes_gpc' => ['T', '@phpstan-template' => 'T', 'gpc' => 'T'],
     'add_submenu_page' => [null, 'callback' => "''|callable"],
diff --git a/tests/data/_get_list_table.php b/tests/data/_get_list_table.php
index ec355b6..72c9ab0 100644
--- a/tests/data/_get_list_table.php
+++ b/tests/data/_get_list_table.php
@@ -7,8 +7,16 @@
 use function _get_list_table;
 use function PHPStan\Testing\assertType;
 
-assertType('false', _get_list_table('Not_WP_List_Table'));
+// A non-class-string
+assertType('false', _get_list_table('string'));
 
+// A class-string that is not class-string<WP_List_Table>
+assertType('false', _get_list_table('WP_Post'));
+
+// WP_List_Table itself
+assertType('false', _get_list_table('WP_List_Table'));
+
+// Core WP_List_Table classes
 assertType('WP_Posts_List_Table', _get_list_table('WP_Posts_List_Table'));
 assertType('WP_Media_List_Table', _get_list_table('WP_Media_List_Table'));
 assertType('WP_Terms_List_Table', _get_list_table('WP_Terms_List_Table'));
@@ -18,7 +26,6 @@
 assertType('WP_Links_List_Table', _get_list_table('WP_Links_List_Table'));
 assertType('WP_Plugin_Install_List_Table', _get_list_table('WP_Plugin_Install_List_Table'));
 assertType('WP_Themes_List_Table', _get_list_table('WP_Themes_List_Table'));
-assertType('WP_Theme_Install_List_Table', _get_list_table('WP_Theme_Install_List_Table'));
 assertType('WP_Plugins_List_Table', _get_list_table('WP_Plugins_List_Table'));
 assertType('WP_Application_Passwords_List_Table', _get_list_table('WP_Application_Passwords_List_Table'));
 assertType('WP_MS_Sites_List_Table', _get_list_table('WP_MS_Sites_List_Table'));
@@ -26,3 +33,18 @@
 assertType('WP_MS_Themes_List_Table', _get_list_table('WP_MS_Themes_List_Table'));
 assertType('WP_Privacy_Data_Export_Requests_List_Table', _get_list_table('WP_Privacy_Data_Export_Requests_List_Table'));
 assertType('WP_Privacy_Data_Removal_Requests_List_Table', _get_list_table('WP_Privacy_Data_Removal_Requests_List_Table'));
+
+// Union of core WP_List_Table classes
+assertType('WP_Media_List_Table|WP_Posts_List_Table', _get_list_table(isset($_GET['foo']) ? 'WP_Posts_List_Table' : 'WP_Media_List_Table'));
+
+// Union of core WP_List_Table class and class that is not a subclass of WP_List_Table
+assertType('WP_Posts_List_Table|false', _get_list_table(isset($_GET['foo']) ? 'WP_Posts_List_Table' : 'WP_Post'));
+
+// WP_Post_Comments_List_Table is generalized WP_Comments_List_Table
+assertType('WP_Comments_List_Table', _get_list_table(isset($_GET['foo']) ? 'WP_Comments_List_Table' : 'WP_Post_Comments_List_Table'));
+
+// WP_Theme_Install_List_Table is generalized to WP_Themes_List_Table
+assertType('WP_Themes_List_Table', _get_list_table(isset($_GET['foo']) ? 'WP_Themes_List_Table' : 'WP_Theme_Install_List_Table'));
+
+// Unknown string
+assertType('WP_Application_Passwords_List_Table|WP_Comments_List_Table|WP_Links_List_Table|WP_Media_List_Table|WP_MS_Sites_List_Table|WP_MS_Themes_List_Table|WP_MS_Users_List_Table|WP_Plugin_Install_List_Table|WP_Plugins_List_Table|WP_Posts_List_Table|WP_Privacy_Data_Export_Requests_List_Table|WP_Privacy_Data_Removal_Requests_List_Table|WP_Terms_List_Table|WP_Themes_List_Table|WP_Users_List_Table|false', _get_list_table(Faker::string()));
diff --git a/wordpress-stubs.php b/wordpress-stubs.php
index 88476e1..84d1752 100644
--- a/wordpress-stubs.php
+++ b/wordpress-stubs.php
@@ -82014,10 +82014,10 @@ function wp_get_popular_importers()
      * @param string $class_name The type of the list table, which is the class name.
      * @param array  $args       Optional. Arguments to pass to the class. Accepts 'screen'.
      * @return WP_List_Table|false List table object on success, false if the class does not exist.
-     * @phpstan-template T
-     * @phpstan-param class-string<T> $class_name
+     * @phpstan-template T of string
+     * @phpstan-param T $class_name
      * @phpstan-param array{screen?: string} $args
-     * @phpstan-return ($class_name is 'WP_Posts_List_Table'|'WP_Media_List_Table'|'WP_Terms_List_Table'|'WP_Users_List_Table'|'WP_Comments_List_Table'|'WP_Post_Comments_List_Table'|'WP_Links_List_Table'|'WP_Plugin_Install_List_Table'|'WP_Themes_List_Table'|'WP_Theme_Install_List_Table'|'WP_Plugins_List_Table'|'WP_Application_Passwords_List_Table'|'WP_MS_Sites_List_Table'|'WP_MS_Users_List_Table'|'WP_MS_Themes_List_Table'|'WP_Privacy_Data_Export_Requests_List_Table'|'WP_Privacy_Data_Removal_Requests_List_Table' ? T : false)
+     * @phpstan-return ($class_name is 'WP_Posts_List_Table'|'WP_Media_List_Table'|'WP_Terms_List_Table'|'WP_Users_List_Table'|'WP_Comments_List_Table'|'WP_Post_Comments_List_Table'|'WP_Links_List_Table'|'WP_Plugin_Install_List_Table'|'WP_Themes_List_Table'|'WP_Theme_Install_List_Table'|'WP_Plugins_List_Table'|'WP_Application_Passwords_List_Table'|'WP_MS_Sites_List_Table'|'WP_MS_Users_List_Table'|'WP_MS_Themes_List_Table'|'WP_Privacy_Data_Export_Requests_List_Table'|'WP_Privacy_Data_Removal_Requests_List_Table' ? new<T> : false)
      */
     function _get_list_table($class_name, $args = array())
     {