logicalOr.leftNotBoolean

Code example

<?php declare(strict_types = 1);

$string = 'str';
$bool = true;

if ($string or $bool) {
	// ...
}

Why is it reported?

The left side of the or expression is not a boolean value. PHP will implicitly cast the non-boolean value to bool before evaluating the expression. This implicit type coercion can lead to unexpected behaviour depending on PHP's type juggling rules.

This rule is part of phpstan-strict-rules and enforces that only boolean values are used with the or operator, making the code's intent explicit.

The or keyword is the low-precedence version of ||. This identifier specifically covers the or keyword; for ||, see booleanOr.leftNotBoolean.

In the example above, $string is of type string, not bool, so using it on the left side of or relies on PHP's loose type coercion.

How to fix it

Use an explicit comparison to produce a boolean value:

 <?php declare(strict_types = 1);

 $string = 'str';
 $bool = true;

-if ($string or $bool) {
+if ($string !== '' or $bool) {
 	// ...
 }

Or convert the value to boolean with a meaningful comparison:

 <?php declare(strict_types = 1);

 $string = 'str';
 $bool = true;

-if ($string or $bool) {
+if (strlen($string) > 0 or $bool) {
 	// ...
 }