[DowngradePhp81] Handle abstract method on DowngradeNewInInitializerR…

…ector

rules-tests/DowngradePhp81/Rector/FunctionLike/DowngradeNewInInitializerRector/Fixture/in_abstract_method.php.inc

@@ -0,0 +1,19 @@
+<?php
+
+namespace Rector\Tests\DowngradePhp81\Rector\FunctionLike\DowngradeNewInInitializerRector\Fixture;
+
+interface MyInterface {
+    public function myMethod(\stdClass $my_instance = new \stdClass());
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\DowngradePhp81\Rector\FunctionLike\DowngradeNewInInitializerRector\Fixture;
+
+interface MyInterface {
+    public function myMethod(\stdClass $my_instance = null);
+}
+
+?>

rules/DowngradePhp81/Rector/FunctionLike/DowngradeNewInInitializerRector.php

@@ -180,6 +180,10 @@ private function replaceNewInParams(ClassMethod|Closure|Function_ $functionLike)
             $param->default = $this->nodeFactory->createNull();
         }
 
+        if ($functionLike->stmts === null) {
+            return $functionLike;
+        }
+
         $functionLike->stmts ??= [];
         $functionLike->stmts = array_merge($stmts, $functionLike->stmts);