Error Identifier: new.trait

← Back to new.*

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 #

<?php declare(strict_types = 1);

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

$obj = new MyTrait(); // error: Cannot instantiate trait MyTrait.

Why is it reported? #

Traits in PHP are not standalone classes and cannot be instantiated with the new keyword. A trait is a mechanism for code reuse — it provides methods that can be included in one or more classes using the use keyword. Attempting to instantiate a trait will result in a fatal error at runtime.

How to fix it #

Use the trait inside a class and instantiate that class instead:

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

+class MyClass
+{
+	use MyTrait;
+}
+
-$obj = new MyTrait();
+$obj = new MyClass();

How to ignore this error #

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

// @phpstan-ignore new.trait
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: new.trait

Rules that report this error #

• PHPStan\Rules\Classes\InstantiationRule [1]