TypeString::normalizeCase(): normalize FQN true/false/null to unqualified

Includes tests.

Author: jrfnl

PHPCSUtils/Utils/TypeString.php

@@ -137,6 +137,8 @@ public static function isKeyword($type)
      * Normalize the case for a single type.
      *
      * - Types which are recognized PHP "keyword" types will be returned in lowercase.
+     * - Types which are recognized PHP "keyword" types and can be fully qualified (true/false/null)
+     *   will be returned as unqualified.
      * - Class/Interface/Enum names will be returned in their original case.
      *
      * @since 1.1.0
@@ -152,7 +154,7 @@ public static function normalizeCase($type)
         }
 
         if (self::isKeyword($type)) {
-            return \strtolower($type);
+            return \strtolower(\ltrim($type, '\\'));
         }
 
         return $type;

Tests/Utils/TypeString/NormalizeCaseTest.php

@@ -135,6 +135,31 @@ public static function dataNormalizeCase()
             ];
         }
 
+        $data['true: fully qualified']             = [
+            'type'     => '\true',
+            'expected' => 'true',
+        ];
+        $data['false: fully qualified']            = [
+            'type'     => '\false',
+            'expected' => 'false',
+        ];
+        $data['null: fully qualified']             = [
+            'type'     => '\null',
+            'expected' => 'null',
+        ];
+        $data['true: fully qualified, uppercase']  = [
+            'type'     => '\TRUE',
+            'expected' => 'true',
+        ];
+        $data['false: fully qualified, uppercase'] = [
+            'type'     => '\FALSE',
+            'expected' => 'false',
+        ];
+        $data['null: fully qualified, uppercase']  = [
+            'type'     => '\NULL',
+            'expected' => 'null',
+        ];
+
         $data['Classname: UnqualifiedName'] = [
             'type'     => 'UnqualifiedName',
             'expected' => 'UnqualifiedName',