---
layout: docs
title: allowsSubtyping
id: class.Facebook.HackCodegen.CodegenShape.allowsSubtyping
docid: class.Facebook.HackCodegen.CodegenShape.allowsSubtyping
permalink: /docs/reference/class.Facebook.HackCodegen.CodegenShape.allowsSubtyping/
---
# Facebook\\HackCodegen\\CodegenShape::allowsSubtyping()




``` Hack
public function allowsSubtyping(): bool;
```




## Returns




* ` bool `