Error Identifier: trait.duplicate

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Every error reported by PHPStan has an error identifier. Here’s a list of all error identifiers. In PHPStan Pro you can see the error identifier next to each error and filter errors by their identifiers.

Code example #

This error is reported when the same trait name is declared in multiple files within the analysed codebase:

// file1.php
<?php declare(strict_types = 1);

namespace App\Helpers;

trait MyTrait
{
	public function doSomething(): void
	{
	}
}

// file2.php
<?php declare(strict_types = 1);

namespace App\Helpers;

trait MyTrait
{
	public function doSomethingElse(): void
	{
	}
}

Why is it reported? #

The same trait name is declared in multiple files within the registered stub files.

How to fix it #

Rename one of the duplicate traits to give it a unique fully qualified name:

 <?php declare(strict_types = 1);
 
 // file2.php
-namespace App\Helpers;
+namespace App\Legacy;

-trait MyTrait
+trait LegacyTrait
 {
 	public function doSomethingElse(): void
 	{
 	}
 }

Or remove the duplicate declaration if it was unintentional.

How to ignore this error #

You can use the identifier trait.duplicate to ignore this error using a comment:

// @phpstan-ignore trait.duplicate
codeThatProducesTheError();

You can also use only the identifier key to ignore all errors of the same type in your configuration file in the ignoreErrors parameter:

parameters:
	ignoreErrors:
		-
			identifier: trait.duplicate

Rules that report this error #

• PHPStan\Rules\Classes\DuplicateClassDeclarationRule [1]