diff --git a/rules-tests/DeadCode/Rector/MethodCall/RemoveNullArgOnNullDefaultParamRector/Fixture/with_function_call.php.inc b/rules-tests/DeadCode/Rector/MethodCall/RemoveNullArgOnNullDefaultParamRector/Fixture/with_function_call.php.inc
new file mode 100644
index 00000000000..c8c068ea12f
--- /dev/null
+++ b/rules-tests/DeadCode/Rector/MethodCall/RemoveNullArgOnNullDefaultParamRector/Fixture/with_function_call.php.inc
@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\Tests\DeadCode\Rector\MethodCall\RemoveNullArgOnNullDefaultParamRector\Fixture;
+
+function SomeFunctionWithDefaultNullArg(?string $someClass = null)
+{
+}
+
+SomeFunctionWithDefaultNullArg(null);
+
+?>
+-----
+<?php
+
+declare(strict_types=1);
+
+namespace Rector\Tests\DeadCode\Rector\MethodCall\RemoveNullArgOnNullDefaultParamRector\Fixture;
+
+function SomeFunctionWithDefaultNullArg(?string $someClass = null)
+{
+}
+
+SomeFunctionWithDefaultNullArg();
+
+?>
diff --git a/rules/DeadCode/NodeAnalyzer/CallLikeParamDefaultResolver.php b/rules/DeadCode/NodeAnalyzer/CallLikeParamDefaultResolver.php
index 47f7a23a51b..c10095efc36 100644
--- a/rules/DeadCode/NodeAnalyzer/CallLikeParamDefaultResolver.php
+++ b/rules/DeadCode/NodeAnalyzer/CallLikeParamDefaultResolver.php
@@ -4,9 +4,11 @@
 
 namespace Rector\DeadCode\NodeAnalyzer;
 
+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;
 use PHPStan\Reflection\ParametersAcceptorSelector;
 use PHPStan\Type\NullType;
@@ -22,16 +24,16 @@ public function __construct(
     /**
      * @return int[]
      */
-    public function resolveNullPositions(MethodCall|StaticCall|New_ $callLike): array
+    public function resolveNullPositions(MethodCall|StaticCall|New_|FuncCall $callLike): array
     {
-        $methodReflection = $this->reflectionResolver->resolveFunctionLikeReflectionFromCall($callLike);
-        if (! $methodReflection instanceof MethodReflection) {
+        $reflection = $this->reflectionResolver->resolveFunctionLikeReflectionFromCall($callLike);
+        if (! $reflection instanceof MethodReflection && ! $reflection instanceof FunctionReflection) {
             return [];
         }
 
         $nullPositions = [];
 
-        $extendedParametersAcceptor = ParametersAcceptorSelector::combineAcceptors($methodReflection->getVariants());
+        $extendedParametersAcceptor = ParametersAcceptorSelector::combineAcceptors($reflection->getVariants());
         foreach ($extendedParametersAcceptor->getParameters() as $position => $extendedParameterReflection) {
             if (! $extendedParameterReflection->getDefaultValue() instanceof NullType) {
                 continue;
@@ -43,14 +45,16 @@ public function resolveNullPositions(MethodCall|StaticCall|New_ $callLike): arra
         return $nullPositions;
     }
 
-    public function resolvePositionParameterByName(MethodCall|StaticCall|New_ $callLike, string $parameterName): ?int
-    {
-        $methodReflection = $this->reflectionResolver->resolveFunctionLikeReflectionFromCall($callLike);
-        if (! $methodReflection instanceof MethodReflection) {
+    public function resolvePositionParameterByName(
+        MethodCall|StaticCall|New_|FuncCall $callLike,
+        string $parameterName
+    ): ?int {
+        $reflection = $this->reflectionResolver->resolveFunctionLikeReflectionFromCall($callLike);
+        if (! $reflection instanceof MethodReflection && ! $reflection instanceof FunctionReflection) {
             return null;
         }
 
-        $extendedParametersAcceptor = ParametersAcceptorSelector::combineAcceptors($methodReflection->getVariants());
+        $extendedParametersAcceptor = ParametersAcceptorSelector::combineAcceptors($reflection->getVariants());
         foreach ($extendedParametersAcceptor->getParameters() as $position => $extendedParameterReflection) {
             if ($extendedParameterReflection->getName() === $parameterName) {
                 return $position;
diff --git a/rules/DeadCode/Rector/MethodCall/RemoveNullArgOnNullDefaultParamRector.php b/rules/DeadCode/Rector/MethodCall/RemoveNullArgOnNullDefaultParamRector.php
index f8cc84bd9d3..568a1063eb1 100644
--- a/rules/DeadCode/Rector/MethodCall/RemoveNullArgOnNullDefaultParamRector.php
+++ b/rules/DeadCode/Rector/MethodCall/RemoveNullArgOnNullDefaultParamRector.php
@@ -5,6 +5,7 @@
 namespace Rector\DeadCode\Rector\MethodCall;
 
 use PhpParser\Node;
+use PhpParser\Node\Expr\FuncCall;
 use PhpParser\Node\Expr\MethodCall;
 use PhpParser\Node\Expr\New_;
 use PhpParser\Node\Expr\StaticCall;
@@ -71,13 +72,13 @@ public function execute(?SomeClass $someClass = null)
 
     public function getNodeTypes(): array
     {
-        return [MethodCall::class, StaticCall::class, New_::class];
+        return [MethodCall::class, StaticCall::class, New_::class, FuncCall::class];
     }
 
     /**
-     * @param MethodCall|StaticCall|New_ $node
+     * @param MethodCall|StaticCall|New_|FuncCall $node
      */
-    public function refactor(Node $node): StaticCall|MethodCall|New_|null
+    public function refactor(Node $node): StaticCall|MethodCall|New_|FuncCall|null
     {
         if ($node->isFirstClassCallable()) {
             return null;
@@ -87,8 +88,12 @@ public function refactor(Node $node): StaticCall|MethodCall|New_|null
             return null;
         }
 
-        $hasChanged = false;
+        $nullPositions = $this->callLikeParamDefaultResolver->resolveNullPositions($node);
+        if ($nullPositions === []) {
+            return null;
+        }
 
+        $hasChanged = false;
         $args = $node->getArgs();
         $lastArgPosition = count($args) - 1;
         for ($position = $lastArgPosition; $position >= 0; --$position) {
@@ -114,8 +119,7 @@ public function refactor(Node $node): StaticCall|MethodCall|New_|null
                 break;
             }
 
-            $nullPositions = $this->callLikeParamDefaultResolver->resolveNullPositions($node);
-            if (! in_array($position, $nullPositions)) {
+            if (! in_array($position, $nullPositions, true)) {
                 break;
             }