Error Identifier: preInc.nonNumeric

← Back to preInc.*

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.

This error is reported by phpstan/phpstan-strict-rules.

Code example #

<?php declare(strict_types = 1);

function increment(bool $flag): int
{
	return ++$flag;
}

Why is it reported? #

The ++ (pre-increment) operator is being used on a value that is not numeric. While PHP allows incrementing non-numeric types like bool, this behaviour can be surprising and error-prone. The strict rules require that only numeric types (int or float) are used with the increment operator to prevent unintended results.

How to fix it #

Ensure the variable is typed as int if you intend numeric increment:

 <?php declare(strict_types = 1);
 
-function increment(bool $flag): int
+function increment(int $counter): int
 {
-	return ++$flag;
+	return ++$counter;
 }

How to ignore this error #

You can use the identifier preInc.nonNumeric to ignore this error using a comment:

// @phpstan-ignore preInc.nonNumeric
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: preInc.nonNumeric

Rules that report this error #

• PHPStan\Rules\Operators\OperandInArithmeticIncrementOrDecrementRule [1] phpstan/phpstan-strict-rules