diff --git a/rules-tests/TypeDeclaration/Rector/ClassMethod/AddMethodCallBasedStrictParamTypeRector/Fixture/unique_types.php.inc b/rules-tests/TypeDeclaration/Rector/ClassMethod/AddMethodCallBasedStrictParamTypeRector/Fixture/unique_types.php.inc
new file mode 100644
index 00000000000..47ef84af009
--- /dev/null
+++ b/rules-tests/TypeDeclaration/Rector/ClassMethod/AddMethodCallBasedStrictParamTypeRector/Fixture/unique_types.php.inc
@@ -0,0 +1,39 @@
+<?php
+
+namespace Rector\Tests\TypeDeclaration\Rector\ClassMethod\AddMethodCallBasedStrictParamTypeRector\Fixture;
+
+final class UniqueTypes
+{
+    public function run()
+    {
+        $this->getById(5);
+        $this->getById(null);
+        $this->getById(5);
+    }
+
+    private function getById($id)
+    {
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\TypeDeclaration\Rector\ClassMethod\AddMethodCallBasedStrictParamTypeRector\Fixture;
+
+final class UniqueTypes
+{
+    public function run()
+    {
+        $this->getById(5);
+        $this->getById(null);
+        $this->getById(5);
+    }
+
+    private function getById(?int $id)
+    {
+    }
+}
+
+?>