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




``` Hack
protected function buildDeclaration(
  Facebook\HackCodegen\HackBuilder $builder,
): void;
```




## Parameters




- [` Facebook\HackCodegen\HackBuilder `](<class.Facebook.HackCodegen.HackBuilder.md>)`` $builder ``




## Returns




+ ` void `