diff --git a/rules-tests/TypeDeclarationDocblocks/Rector/Class_/ClassMethodArrayDocblockParamFromLocalCallsRector/Fixture/not_zero_position.php.inc b/rules-tests/TypeDeclarationDocblocks/Rector/Class_/ClassMethodArrayDocblockParamFromLocalCallsRector/Fixture/not_zero_position.php.inc
new file mode 100644
index 00000000000..b246c65ec18
--- /dev/null
+++ b/rules-tests/TypeDeclarationDocblocks/Rector/Class_/ClassMethodArrayDocblockParamFromLocalCallsRector/Fixture/not_zero_position.php.inc
@@ -0,0 +1,38 @@
+<?php
+
+namespace Rector\Tests\TypeDeclarationDocblocks\Rector\Class_\ClassMethodArrayDocblockParamFromLocalCallsRector\Fixture;
+
+class NotZeroPosition
+{
+    public function go()
+    {
+        $this->run([], ['item1', 'item2']);
+    }
+
+    private function run(array $data, array $items)
+    {
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\TypeDeclarationDocblocks\Rector\Class_\ClassMethodArrayDocblockParamFromLocalCallsRector\Fixture;
+
+class NotZeroPosition
+{
+    public function go()
+    {
+        $this->run([], ['item1', 'item2']);
+    }
+
+    /**
+     * @param string[] $items
+     */
+    private function run(array $data, array $items)
+    {
+    }
+}
+
+?>
diff --git a/rules/TypeDeclaration/NodeAnalyzer/CallTypesResolver.php b/rules/TypeDeclaration/NodeAnalyzer/CallTypesResolver.php
index a29dbc2fc20..0f5ad1c4cc3 100644
--- a/rules/TypeDeclaration/NodeAnalyzer/CallTypesResolver.php
+++ b/rules/TypeDeclaration/NodeAnalyzer/CallTypesResolver.php
@@ -124,17 +124,13 @@ private function unionToSingleType(array $staticTypesByArgumentPosition): array
             $staticTypeByArgumentPosition[$position] = $this->narrowParentObjectTreeToSingleObjectChildType(
                 $unionedType
             );
-        }
-
-        if (count($staticTypeByArgumentPosition) !== 1) {
-            return $staticTypeByArgumentPosition;
-        }
 
-        if (! $staticTypeByArgumentPosition[0]->isNull()->yes()) {
-            return $staticTypeByArgumentPosition;
+            if ($staticTypeByArgumentPosition[$position]->isNull()->yes()) {
+                $staticTypeByArgumentPosition[$position] = new MixedType();
+            }
         }
 
-        return [new MixedType()];
+        return $staticTypeByArgumentPosition;
     }
 
     private function narrowParentObjectTreeToSingleObjectChildType(Type $type): Type