logicalXor.rightAlwaysFalse

Code example

<?php declare(strict_types = 1);

function doFoo(bool $flag): bool
{
	$f = false;
	return $flag xor $f;
}

Why is it reported?

The right side of the xor operator always evaluates to false. This makes the xor expression equivalent to just the left side, because $left xor false always equals $left. The right operand is redundant and likely indicates a logic error.

In the example above, $f is always false, so $flag xor $f is equivalent to $flag.

How to fix it

Simplify the expression by removing the redundant xor:

 <?php declare(strict_types = 1);

 function doFoo(bool $flag): bool
 {
-	$f = false;
-	return $flag xor $f;
+	return $flag;
 }

Or fix the right-side condition so that it can actually evaluate to true:

 <?php declare(strict_types = 1);

-function doFoo(bool $flag): bool
+function doFoo(bool $flag, bool $other): bool
 {
-	$f = false;
-	return $flag xor $f;
+	return $flag xor $other;
 }