notEqual.notAllowed

Code example

<?php declare(strict_types = 1);

$result = 123 != 456; // error: Loose comparison via "!=" is not allowed.

Why is it reported?

Loose comparison (!=) uses PHP's type juggling rules to compare values, which can produce surprising and hard-to-predict results. For example, "0" != "" evaluates to true, but 0 != "" evaluates to false. These implicit type conversions are a common source of bugs.

This error is reported by phpstan-strict-rules.

How to fix it

Use strict comparison (!==) instead, which compares both the value and the type without implicit conversion.

-$result = 123 != 456;
+$result = 123 !== 456;

If the values have different types and a comparison is still needed, cast one operand explicitly to make the intent clear.

-if ($userInput != 0) {
+if ((int) $userInput !== 0) {
 	// ...
 }