Error Identifier: unaryPlus.nonNumeric

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);

function doFoo(?int $value): void
{
	$result = +$value;
}

Why is it reported? #

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

The unary + operator is applied to a non-numeric value. The unary plus operator is intended for numeric types (int, float). When applied to non-numeric types like null, string, or objects, PHP silently coerces the value, which can lead to unexpected results and hides type errors.

How to fix it #

Ensure the operand is a numeric type before applying unary +:

 function doFoo(?int $value): void
 {
-	$result = +$value;
+	if ($value !== null) {
+		$result = +$value;
+	}
 }

Or cast the value explicitly if the coercion is intentional:

 function doFoo(?int $value): void
 {
-	$result = +$value;
+	$result = (int) $value;
 }

How to ignore this error #

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

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

Rules that report this error #

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

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