fix lowercase of union fqn types

packages/NodeTypeResolver/src/Php/AbstractTypeInfo.php

@@ -257,15 +257,14 @@ private function normalizeNullable(string $type): string
 
     private function normalizeCasing(string $type): string
     {
-        if ($this->typeAnalyzer->isPhpReservedType($type)) {
-            return strtolower($type);
-        }
-
-        if (strtolower($type) === '$this') {
-            return strtolower($type);
+        $types = explode('|', $type);
+        foreach ($types as $key => $singleType) {
+            if ($this->typeAnalyzer->isPhpReservedType($singleType) || strtolower($singleType) === '$this') {
+                $types[$key] = strtolower($singleType);
+            }
         }
 
-        return $type;
+        return implode($types, '|');
     }
 
     /**

packages/TypeDeclaration/tests/Rector/ClassMethod/AddArrayReturnDocTypeRector/AddArrayReturnDocTypeRectorTest.php

@@ -9,7 +9,11 @@ final class AddArrayReturnDocTypeRectorTest extends AbstractRectorTestCase
 {
     public function test(): void
     {
-        $this->doTestFiles([__DIR__ . '/Fixture/fixture.php.inc', __DIR__ . '/Fixture/setter_based.php.inc']);
+        $this->doTestFiles([
+            __DIR__ . '/Fixture/fixture.php.inc',
+            __DIR__ . '/Fixture/setter_based.php.inc',
+            __DIR__ . '/Fixture/fully_qualified_name.php.inc',
+        ]);
     }
 
     protected function getRectorClass(): string

packages/TypeDeclaration/tests/Rector/ClassMethod/AddArrayReturnDocTypeRector/Fixture/fully_qualified_name.php.inc

@@ -0,0 +1,55 @@
+<?php
+
+namespace Rector\TypeDeclaration\Tests\Rector\ClassMethod\AddArrayReturnDocTypeRector\Fixture;
+
+use Rector\TypeDeclaration\Tests\Rector\ClassMethod\AddArrayReturnDocTypeRector\Source\ValidationResult;
+
+final class FullyQualifiedName
+{
+    public function isValidDataProvider(): array
+    {
+        return [
+            new ValidationResult(), true,
+        ];
+    }
+
+    public function getValidationErrorMessagesAsStringDataProvider(): array
+    {
+        return [
+            'no_errors' => [new ValidationResult(), 'ha_ja'],
+        ];
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\TypeDeclaration\Tests\Rector\ClassMethod\AddArrayReturnDocTypeRector\Fixture;
+
+use Rector\TypeDeclaration\Tests\Rector\ClassMethod\AddArrayReturnDocTypeRector\Source\ValidationResult;
+
+final class FullyQualifiedName
+{
+    /**
+     * @return \Rector\TypeDeclaration\Tests\Rector\ClassMethod\AddArrayReturnDocTypeRector\Source\ValidationResult[]|bool[]
+     */
+    public function isValidDataProvider(): array
+    {
+        return [
+            new ValidationResult(), true,
+        ];
+    }
+
+    /**
+     * @return string[][]|\Rector\TypeDeclaration\Tests\Rector\ClassMethod\AddArrayReturnDocTypeRector\Source\ValidationResult[][]
+     */
+    public function getValidationErrorMessagesAsStringDataProvider(): array
+    {
+        return [
+            'no_errors' => [new ValidationResult(), 'ha_ja'],
+        ];
+    }
+}
+
+?>

packages/TypeDeclaration/tests/Rector/ClassMethod/AddArrayReturnDocTypeRector/Source/ValidationResult.php

@@ -0,0 +1,8 @@
+<?php declare(strict_types=1);
+
+namespace Rector\TypeDeclaration\Tests\Rector\ClassMethod\AddArrayReturnDocTypeRector\Source;
+
+final class ValidationResult
+{
+
+}