equal.notAllowed

Code example

<?php declare(strict_types = 1);

function check(int $a, int $b): bool
{
	return $a == $b;
}

Why is it reported?

This error is reported by phpstan/phpstan-strict-rules.

Loose comparison via == is not allowed. The == operator performs type juggling before comparing values, which can lead to unexpected results. For example, 0 == 'foo' evaluates to true in PHP versions before 8.0, and '' == null is true in all versions.

Using strict comparison (===) avoids these pitfalls by comparing both value and type.

How to fix it

Replace the loose comparison operator with its strict equivalent:

 <?php declare(strict_types = 1);

 function check(int $a, int $b): bool
 {
-	return $a == $b;
+	return $a === $b;
 }