logicalXor.leftAlwaysTrue

Code example

<?php declare(strict_types = 1);

function doFoo(bool $b): void
{
	if (1 xor $b) {
		// ...
	}
}

Why is it reported?

The left side of the xor expression always evaluates to true. This means the result of the xor is equivalent to the negation of the right side, making the xor operator misleading.

The logical xor operator returns true when exactly one of its operands is true. If the left side is always true, the result is always the opposite of the right side.

How to fix it

Replace the xor with a negation of the right operand:

-if (1 xor $b) {
+if (!$b) {
 	// ...
 }

If the constant value is unintentional, fix the left operand so it can actually be true or false:

-if (1 xor $b) {
+if ($a xor $b) {
 	// ...
 }