Error Identifier: classConstant.type

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);

class ParentClass
{
	/** @var positive-int */
	public const VALUE = 1;
}

class ChildClass extends ParentClass
{
	/** @var int */
	public const VALUE = -1;
}

Why is it reported? #

The type of an overriding class constant is not covariant with the type of the constant in the parent class. When a child class overrides a constant from a parent class, the child’s constant type must be a subtype of (or equal to) the parent’s constant type. This ensures that code relying on the parent’s type contract remains valid.

In the example above, ParentClass::VALUE is typed as positive-int, but ChildClass::VALUE widens the type to int and assigns -1, which violates the parent’s type contract.

How to fix it #

Ensure the overriding constant’s type is a subtype of the parent’s type:

 <?php declare(strict_types = 1);
 
 class ChildClass extends ParentClass
 {
-	/** @var int */
-	public const VALUE = -1;
+	/** @var positive-int */
+	public const VALUE = 2;
 }

How to ignore this error #

You can use the identifier classConstant.type to ignore this error using a comment:

// @phpstan-ignore classConstant.type
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: classConstant.type

Rules that report this error #

PHPStan\Rules\Constants\OverridingConstantRule [1]

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