[DeadCode] Skip with use of func_num_args() on RemoveNullArgOnNullDefaultParamRector

rules-tests/DeadCode/Rector/MethodCall/RemoveNullArgOnNullDefaultParamRector/Fixture/skip_with_useof_func_num_args.php.inc

@@ -0,0 +1,26 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\Tests\DeadCode\Rector\MethodCall\RemoveNullArgOnNullDefaultParamRector\Fixture;
+
+/**
+ * @see https://3v4l.org/RCVaU#v8.3.9 vs https://3v4l.org/6DSlE#v8.3.9
+ */
+final class SkipWithUseOfFuncNumArgs
+{
+    private $b = 1;
+
+    public function set($a, $b = null)
+    {
+        if (func_num_args() > 1) {
+            $this->b = $b;
+        }
+    }
+
+    public function get()
+    {
+        $this->set(1, null);
+        return $this->b;
+    }
+}

rules/DeadCode/NodeAnalyzer/CallLikeParamDefaultResolver.php

@@ -12,12 +12,14 @@
 use PHPStan\Reflection\MethodReflection;
 use PHPStan\Reflection\ParametersAcceptorSelector;
 use PHPStan\Type\NullType;
+use Rector\NodeAnalyzer\VariadicAnalyzer;
 use Rector\Reflection\ReflectionResolver;
 
 final readonly class CallLikeParamDefaultResolver
 {
     public function __construct(
         private ReflectionResolver $reflectionResolver,
+        private VariadicAnalyzer $variadicAnalyzer,
     ) {
     }
 
@@ -38,6 +40,10 @@ public function resolveNullPositions(MethodCall|StaticCall|New_|FuncCall $callLi
             }
         }
 
+        if ($this->variadicAnalyzer->hasVariadicParameters($callLike)) {
+            return [];
+        }
+
         $nullPositions = [];
 
         $extendedParametersAcceptor = ParametersAcceptorSelector::combineAcceptors($reflection->getVariants());

src/NodeAnalyzer/VariadicAnalyzer.php

@@ -6,6 +6,7 @@
 
 use PhpParser\Node\Expr\FuncCall;
 use PhpParser\Node\Expr\MethodCall;
+use PhpParser\Node\Expr\New_;
 use PhpParser\Node\Expr\StaticCall;
 use PHPStan\Reflection\FunctionReflection;
 use PHPStan\Reflection\MethodReflection;
@@ -18,7 +19,7 @@ public function __construct(
     ) {
     }
 
-    public function hasVariadicParameters(FuncCall | StaticCall | MethodCall $call): bool
+    public function hasVariadicParameters(FuncCall | StaticCall | MethodCall | New_ $call): bool
     {
         $functionLikeReflection = $this->reflectionResolver->resolveFunctionLikeReflectionFromCall($call);
         if ($functionLikeReflection === null) {