Error Identifier: pow.rightNonNumeric

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);

$base = 2;
$exponent = null;

$result = $base ** $exponent;

Why is it reported? #

This error is reported by the phpstan-strict-rules extension.

The right operand of the ** (exponentiation) operator is not a numeric type. PHP will attempt to coerce the value to a number, which can produce unexpected results or warnings. Strict type checking ensures that only int or float values are used in arithmetic operations.

How to fix it #

Ensure the right operand is a numeric type:

 $base = 2;
-$exponent = null;
+$exponent = 3;

 $result = $base ** $exponent;

If the value comes from an external source, validate or cast it before use:

-$result = $base ** $input;
+$result = $base ** (int) $input;

How to ignore this error #

You can use the identifier pow.rightNonNumeric to ignore this error using a comment:

// @phpstan-ignore pow.rightNonNumeric
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: pow.rightNonNumeric

Rules that report this error #

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

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