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booleanOr.resultUnused

website/errors/booleanOr.resultUnused.md

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Code example

php
<?php declare(strict_types = 1);

function doFoo(bool $a, bool $b): void
{
	$a || $b;
}

Why is it reported?

The result of the || (boolean OR) operator is computed but never used. The expression is evaluated as a standalone statement, meaning its result is discarded. This is usually a mistake -- either the result should be assigned to a variable, returned, or used in a condition.

A common cause of this error is confusing || with or. The or operator has lower precedence, which can lead to unexpected behaviour when mixed with assignment.

How to fix it

Assign the result to a variable if it is needed:

diff-php
 <?php declare(strict_types = 1);

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

Or use the expression as a condition:

diff-php
 <?php declare(strict_types = 1);

 function doFoo(bool $a, bool $b): void
 {
-	$a || $b;
+	if ($a || $b) {
+		// do something
+	}
 }

If the intent was to call a function when $a is falsy, consider using an explicit if statement instead:

diff-php
 <?php declare(strict_types = 1);

-function doFoo(bool $a, bool $b): void
+function doFoo(bool $a): void
 {
-	$a || $b;
+	if (!$a) {
+		doSomething();
+	}
 }