diff --git a/rules-tests/TypeDeclarationDocblocks/Rector/Class_/AddReturnDocblockDataProviderRector/Fixture/skip_already_set_type.php.inc b/rules-tests/TypeDeclarationDocblocks/Rector/Class_/AddReturnDocblockDataProviderRector/Fixture/skip_already_set_type.php.inc
new file mode 100644
index 00000000000..b20ce59e523
--- /dev/null
+++ b/rules-tests/TypeDeclarationDocblocks/Rector/Class_/AddReturnDocblockDataProviderRector/Fixture/skip_already_set_type.php.inc
@@ -0,0 +1,37 @@
+<?php
+
+namespace Rector\Tests\TypeDeclarationDocblocks\Rector\Class_\AddReturnDocblockDataProviderRector\Fixture;
+
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\TestCase;
+
+final class SkipAlreadySetType extends TestCase
+{
+    #[DataProvider('provideData')]
+    public function testSomething()
+    {
+    }
+
+    /**
+     * @return \Generator<array<int, array{0: string, 1: string}>>
+     */
+    public static function provideData(): \Generator
+    {
+        yield ['data1', 'data2'];
+        yield ['item4', 'item5'];
+    }
+
+    #[DataProvider('provideDataNext')]
+    public function testSomethingElse()
+    {
+    }
+
+    /**
+     * @return \Iterator<array<int, array{0: string, 1: string}>>
+     */
+    public static function provideDataNext(): \Iterator
+    {
+        yield ['data1', 'data2'];
+        yield ['item4', 'item5'];
+    }
+}
diff --git a/rules-tests/TypeDeclarationDocblocks/Rector/Class_/AddReturnDocblockDataProviderRector/Fixture/union_same_array_type.php.inc b/rules-tests/TypeDeclarationDocblocks/Rector/Class_/AddReturnDocblockDataProviderRector/Fixture/union_same_array_type.php.inc
new file mode 100644
index 00000000000..68a3c43e204
--- /dev/null
+++ b/rules-tests/TypeDeclarationDocblocks/Rector/Class_/AddReturnDocblockDataProviderRector/Fixture/union_same_array_type.php.inc
@@ -0,0 +1,60 @@
+<?php
+
+namespace Rector\Tests\TypeDeclarationDocblocks\Rector\Class_\AddReturnDocblockDataProviderRector\Fixture;
+
+use Nette\Utils\FileSystem;
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\TestCase;
+
+final class UnionSameArrayType extends TestCase
+{
+    #[DataProvider('provideData')]
+    public function testSomething()
+    {
+    }
+
+    public static function provideData(): \Iterator
+    {
+        yield ['...', __DIR__ . '/Source/expected/expected.txt'];
+        yield ["-old\n+new", __DIR__ . '/Source/expected/expected_old_new.txt'];
+
+        yield [
+            FileSystem::read('...'),
+            __DIR__ . '/Fixture/expected_with_full_diff_by_phpunit.diff',
+        ];
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\TypeDeclarationDocblocks\Rector\Class_\AddReturnDocblockDataProviderRector\Fixture;
+
+use Nette\Utils\FileSystem;
+use PHPUnit\Framework\Attributes\DataProvider;
+use PHPUnit\Framework\TestCase;
+
+final class UnionSameArrayType extends TestCase
+{
+    #[DataProvider('provideData')]
+    public function testSomething()
+    {
+    }
+
+    /**
+     * @return \Iterator<array<int, string>>
+     */
+    public static function provideData(): \Iterator
+    {
+        yield ['...', __DIR__ . '/Source/expected/expected.txt'];
+        yield ["-old\n+new", __DIR__ . '/Source/expected/expected_old_new.txt'];
+
+        yield [
+            FileSystem::read('...'),
+            __DIR__ . '/Fixture/expected_with_full_diff_by_phpunit.diff',
+        ];
+    }
+}
+
+?>
diff --git a/tests/BetterPhpDocParser/PhpDocInfo/PhpDocInfoPrinter/MultilineTest.php b/tests/BetterPhpDocParser/PhpDocInfo/PhpDocInfoPrinter/MultilineTest.php
index e4d284f900d..f66d28cd34e 100644
--- a/tests/BetterPhpDocParser/PhpDocInfo/PhpDocInfoPrinter/MultilineTest.php
+++ b/tests/BetterPhpDocParser/PhpDocInfo/PhpDocInfoPrinter/MultilineTest.php
@@ -23,6 +23,9 @@ public function test(string $docFilePath): void
         $this->assertSame($docComment, $printedPhpDocInfo);
     }
 
+    /**
+     * @return Iterator<array<int, string>>
+     */
     public static function provideData(): Iterator
     {
         yield [__DIR__ . '/Source/Multiline/multiline2.txt'];
diff --git a/tests/Console/Formatter/ColorConsoleDiffFormatterTest.php b/tests/Console/Formatter/ColorConsoleDiffFormatterTest.php
index b23764cf93e..e4fd7d4f7c1 100644
--- a/tests/Console/Formatter/ColorConsoleDiffFormatterTest.php
+++ b/tests/Console/Formatter/ColorConsoleDiffFormatterTest.php
@@ -28,6 +28,9 @@ public function test(string $content, string $expectedFormattedFileContent): voi
         $this->assertStringEqualsFile($expectedFormattedFileContent, $formattedContent);
     }
 
+    /**
+     * @return Iterator<array<int, string>>
+     */
     public static function provideData(): Iterator
     {
         yield ['...', __DIR__ . '/Source/expected/expected.txt'];
diff --git a/tests/DependencyInjection/ConfigurableRectorImportConfigCallsMergeTest.php b/tests/DependencyInjection/ConfigurableRectorImportConfigCallsMergeTest.php
index 7f4bbf3a42d..671b7f2ed04 100644
--- a/tests/DependencyInjection/ConfigurableRectorImportConfigCallsMergeTest.php
+++ b/tests/DependencyInjection/ConfigurableRectorImportConfigCallsMergeTest.php
@@ -30,6 +30,9 @@ public function testMainConfigValues(string $configFile, array $expectedConfigur
         $this->assertSame($expectedConfiguration, $renamedClassesDataCollector->getOldToNewClasses());
     }
 
+    /**
+     * @return Iterator<(array<int, array<string, string>>|array<int, string>)>
+     */
     public static function provideData(): Iterator
     {
         yield [
diff --git a/tests/NodeTypeResolver/PerNodeTypeResolver/ClassAndInterfaceTypeResolver/ClassTypeResolverTest.php b/tests/NodeTypeResolver/PerNodeTypeResolver/ClassAndInterfaceTypeResolver/ClassTypeResolverTest.php
index 91baf750762..fd6673a5f1b 100644
--- a/tests/NodeTypeResolver/PerNodeTypeResolver/ClassAndInterfaceTypeResolver/ClassTypeResolverTest.php
+++ b/tests/NodeTypeResolver/PerNodeTypeResolver/ClassAndInterfaceTypeResolver/ClassTypeResolverTest.php
@@ -32,6 +32,9 @@ public function test(string $file, int $nodePosition, ObjectType $expectedObject
         $this->assertSame($expectedObjectType->getClassName(), $resolvedType->getClassName());
     }
 
+    /**
+     * @return Iterator<array<int, (int|ObjectType|string)>>
+     */
     public static function dataProvider(): Iterator
     {
         yield [