Error Identifier: logicalAnd.resultUnused

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(bool $a, bool $b): void
{
	$result = $a and $b;
}

Why is it reported? #

The result of the and operator is unused. This is almost always a bug caused by the unexpected precedence of the and operator. The and operator has lower precedence than =, so $result = $a and $b is parsed as ($result = $a) and $b. The variable $result receives the value of $a, and the and $b part is evaluated but its result is discarded.

How to fix it #

Use && instead of and, which has higher precedence than =:

 function doFoo(bool $a, bool $b): void
 {
-	$result = $a and $b;
+	$result = $a && $b;
 }

Or use parentheses to disambiguate:

 function doFoo(bool $a, bool $b): void
 {
-	$result = $a and $b;
+	$result = ($a and $b);
 }

How to ignore this error #

You can use the identifier logicalAnd.resultUnused to ignore this error using a comment:

// @phpstan-ignore logicalAnd.resultUnused
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: logicalAnd.resultUnused

Rules that report this error #

PHPStan\Rules\DeadCode\NoopRule [1]

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