[Instanceof] Fix combination of dead instance and compare (#5319)

rules/DeadCode/Rector/If_/RemoveDeadInstanceOfRector.php

@@ -4,6 +4,8 @@
 
 namespace Rector\DeadCode\Rector\If_;
 
+use PhpParser\Node\Expr\Assign;
+use PhpParser\Node\Stmt\Expression;
 use PhpParser\Node;
 use PhpParser\Node\Expr;
 use PhpParser\Node\Expr\BooleanNot;
@@ -113,6 +115,11 @@ private function refactorStmtAndInstanceof(If_ $if, Instanceof_ $instanceof): nu
             return null;
         }
 
+        if ($instanceof->expr instanceof Assign) {
+            $assignExpression = new Expression($instanceof->expr);
+            return array_merge([$assignExpression], $if->stmts);
+        }
+
         if ($if->cond !== $instanceof) {
             return NodeTraverser::REMOVE_NODE;
         }

tests/Issues/DeadInstanceFlip/DeadInstanceFlipTest.php

@@ -0,0 +1,28 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\Core\Tests\Issues\DeadInstanceFlip;
+
+use Iterator;
+use PHPUnit\Framework\Attributes\DataProvider;
+use Rector\Testing\PHPUnit\AbstractRectorTestCase;
+
+final class DeadInstanceFlipTest extends AbstractRectorTestCase
+{
+    #[DataProvider('provideData')]
+    public function test(string $filePath): void
+    {
+        $this->doTestFile($filePath);
+    }
+
+    public static function provideData(): Iterator
+    {
+        return self::yieldFilesFromDirectory(__DIR__ . '/Fixture');
+    }
+
+    public function provideConfigFilePath(): string
+    {
+        return __DIR__ . '/config/configured_rule.php';
+    }
+}

tests/Issues/DeadInstanceFlip/Fixture/fixture.php.inc

@@ -0,0 +1,34 @@
+<?php
+
+namespace Rector\Core\Tests\Issues\DeadInstanceFlip\Fixture;
+
+use Rector\Core\Tests\Issues\DeadInstanceFlip\Source\SomeEvent;
+
+final class Fixture
+{
+    public function process(SomeEvent $someEvent)
+    {
+        if (null !== $class = $someEvent->getSomeType()) {
+            $class->result;
+        }
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Core\Tests\Issues\DeadInstanceFlip\Fixture;
+
+use Rector\Core\Tests\Issues\DeadInstanceFlip\Source\SomeEvent;
+
+final class Fixture
+{
+    public function process(SomeEvent $someEvent)
+    {
+        $class = $someEvent->getSomeType();
+        $class->result;
+    }
+}
+
+?>

tests/Issues/DeadInstanceFlip/Source/SomeEvent.php

@@ -0,0 +1,11 @@
+<?php
+
+namespace Rector\Core\Tests\Issues\DeadInstanceFlip\Source;
+
+class SomeEvent
+{
+    public function getSomeType(): SomeEventType
+    {
+
+    }
+}

tests/Issues/DeadInstanceFlip/Source/SomeEventType.php

@@ -0,0 +1,8 @@
+<?php
+
+namespace Rector\Core\Tests\Issues\DeadInstanceFlip\Source;
+
+final class SomeEventType
+{
+    public $result;
+}

tests/Issues/DeadInstanceFlip/config/configured_rule.php

@@ -0,0 +1,11 @@
+<?php
+
+declare(strict_types=1);
+
+use Rector\CodeQuality\Rector\Identical\FlipTypeControlToUseExclusiveTypeRector;
+use Rector\Config\RectorConfig;
+use Rector\DeadCode\Rector\If_\RemoveDeadInstanceOfRector;
+
+return static function (RectorConfig $rectorConfig): void {
+    $rectorConfig->rules([RemoveDeadInstanceOfRector::class, FlipTypeControlToUseExclusiveTypeRector::class]);
+};