diff --git a/rules-tests/TypeDeclarationDocblocks/Rector/ClassMethod/AddParamArrayDocblockFromAssignsParamToParamReferenceRector/Fixture/override_dummy_array_param.php.inc b/rules-tests/TypeDeclarationDocblocks/Rector/ClassMethod/AddParamArrayDocblockFromAssignsParamToParamReferenceRector/Fixture/override_dummy_array_param.php.inc
index 9c26cd1216f..0cf69c874b8 100644
--- a/rules-tests/TypeDeclarationDocblocks/Rector/ClassMethod/AddParamArrayDocblockFromAssignsParamToParamReferenceRector/Fixture/override_dummy_array_param.php.inc
+++ b/rules-tests/TypeDeclarationDocblocks/Rector/ClassMethod/AddParamArrayDocblockFromAssignsParamToParamReferenceRector/Fixture/override_dummy_array_param.php.inc
@@ -7,7 +7,7 @@ final class OverrideDummyArrayParam
     /**
      * @param array $items
      */
-    public function run(array &$items)
+    private function run(array &$items)
     {
         $items[] = 'John';
     }
@@ -24,7 +24,7 @@ final class OverrideDummyArrayParam
     /**
      * @param string[] $items
      */
-    public function run(array &$items)
+    private function run(array &$items)
     {
         $items[] = 'John';
     }
diff --git a/rules-tests/TypeDeclarationDocblocks/Rector/ClassMethod/AddParamArrayDocblockFromAssignsParamToParamReferenceRector/Fixture/skip_dim_fetch_assign_deep.php.inc b/rules-tests/TypeDeclarationDocblocks/Rector/ClassMethod/AddParamArrayDocblockFromAssignsParamToParamReferenceRector/Fixture/skip_dim_fetch_assign_deep.php.inc
index 11c8bba2802..4579d0a78fc 100644
--- a/rules-tests/TypeDeclarationDocblocks/Rector/ClassMethod/AddParamArrayDocblockFromAssignsParamToParamReferenceRector/Fixture/skip_dim_fetch_assign_deep.php.inc
+++ b/rules-tests/TypeDeclarationDocblocks/Rector/ClassMethod/AddParamArrayDocblockFromAssignsParamToParamReferenceRector/Fixture/skip_dim_fetch_assign_deep.php.inc
@@ -4,7 +4,7 @@ namespace Rector\Tests\TypeDeclarationDocblocks\Rector\ClassMethod\AddParamArray
 
 final class SkipDimFetchAssignDeep
 {
-    public function run(array &$items)
+    private function run(array &$items)
     {
         $items[][] = 'John';
     }
diff --git a/rules-tests/TypeDeclarationDocblocks/Rector/ClassMethod/AddParamArrayDocblockFromAssignsParamToParamReferenceRector/Fixture/skip_multiple_assigns.php.inc b/rules-tests/TypeDeclarationDocblocks/Rector/ClassMethod/AddParamArrayDocblockFromAssignsParamToParamReferenceRector/Fixture/skip_multiple_assigns.php.inc
index 864cbcdd14b..2a5c447c7a7 100644
--- a/rules-tests/TypeDeclarationDocblocks/Rector/ClassMethod/AddParamArrayDocblockFromAssignsParamToParamReferenceRector/Fixture/skip_multiple_assigns.php.inc
+++ b/rules-tests/TypeDeclarationDocblocks/Rector/ClassMethod/AddParamArrayDocblockFromAssignsParamToParamReferenceRector/Fixture/skip_multiple_assigns.php.inc
@@ -4,7 +4,7 @@ namespace Rector\Tests\TypeDeclarationDocblocks\Rector\ClassMethod\AddParamArray
 
 final class SkipMultipleAssigns
 {
-    public function run(array &$items)
+    private function run(array &$items)
     {
         $items[] = 'John';
         $items[] = 1000;
diff --git a/rules-tests/TypeDeclarationDocblocks/Rector/ClassMethod/AddParamArrayDocblockFromAssignsParamToParamReferenceRector/Fixture/skip_non_private_method.php.inc b/rules-tests/TypeDeclarationDocblocks/Rector/ClassMethod/AddParamArrayDocblockFromAssignsParamToParamReferenceRector/Fixture/skip_non_private_method.php.inc
new file mode 100644
index 00000000000..8ec801b5dc8
--- /dev/null
+++ b/rules-tests/TypeDeclarationDocblocks/Rector/ClassMethod/AddParamArrayDocblockFromAssignsParamToParamReferenceRector/Fixture/skip_non_private_method.php.inc
@@ -0,0 +1,11 @@
+<?php
+
+namespace Rector\Tests\TypeDeclarationDocblocks\Rector\ClassMethod\AddParamArrayDocblockFromAssignsParamToParamReferenceRector\Fixture;
+
+final class SkipNonPrivateMethod
+{
+    protected function addMobileData(array &$data): void
+    {
+        $data[] = 'value';
+    }
+}
diff --git a/rules-tests/TypeDeclarationDocblocks/Rector/ClassMethod/AddParamArrayDocblockFromAssignsParamToParamReferenceRector/Fixture/some_class.php.inc b/rules-tests/TypeDeclarationDocblocks/Rector/ClassMethod/AddParamArrayDocblockFromAssignsParamToParamReferenceRector/Fixture/some_class.php.inc
index d211184dc3b..c1101914d3a 100644
--- a/rules-tests/TypeDeclarationDocblocks/Rector/ClassMethod/AddParamArrayDocblockFromAssignsParamToParamReferenceRector/Fixture/some_class.php.inc
+++ b/rules-tests/TypeDeclarationDocblocks/Rector/ClassMethod/AddParamArrayDocblockFromAssignsParamToParamReferenceRector/Fixture/some_class.php.inc
@@ -4,7 +4,7 @@ namespace Rector\Tests\TypeDeclarationDocblocks\Rector\ClassMethod\AddParamArray
 
 final class SomeClass
 {
-    public function run(array &$items)
+    private function run(array &$items)
     {
         $items[] = 'John';
     }
@@ -21,7 +21,7 @@ final class SomeClass
     /**
      * @param string[] $items
      */
-    public function run(array &$items)
+    private function run(array &$items)
     {
         $items[] = 'John';
     }
diff --git a/rules/TypeDeclarationDocblocks/Rector/ClassMethod/AddParamArrayDocblockFromAssignsParamToParamReferenceRector.php b/rules/TypeDeclarationDocblocks/Rector/ClassMethod/AddParamArrayDocblockFromAssignsParamToParamReferenceRector.php
index 70de92dddc4..fd1bf67ba10 100644
--- a/rules/TypeDeclarationDocblocks/Rector/ClassMethod/AddParamArrayDocblockFromAssignsParamToParamReferenceRector.php
+++ b/rules/TypeDeclarationDocblocks/Rector/ClassMethod/AddParamArrayDocblockFromAssignsParamToParamReferenceRector.php
@@ -39,7 +39,7 @@ public function getRuleDefinition(): RuleDefinition
                     <<<'CODE_SAMPLE'
 final class SomeClass
 {
-    public function run(array &$names): void
+    private function run(array &$names): void
     {
         $names[] = 'John';
     }
@@ -52,7 +52,7 @@ final class SomeClass
     /**
      * @param string[] $names
      */
-    public function run(array &$names): void
+    private function run(array &$names): void
     {
         $names[] = 'John';
     }
@@ -83,6 +83,11 @@ public function refactor(Node $node): ?Node
             return null;
         }
 
+        // a by-ref param type is invariant in PHPStan; narrowing it below array breaks callers passing a plain array, which are invisible for a non-private method
+        if (! $node->isPrivate()) {
+            return null;
+        }
+
         $phpDocInfo = $this->phpDocInfoFactory->createFromNodeOrEmpty($node);
 
         foreach ($node->getParams() as $param) {