Error Identifier: equal.alwaysTrue

Every error reported by PHPStan has an error identifier. Here’s a list of all error identifiers. In PHPStan Pro you can see the error identifier next to each error and filter errors by their identifiers.

Code example #

<?php declare(strict_types = 1);

function doFoo(): void
{
    if (0 == '0') { // error: Loose comparison using == between 0 and '0' will always evaluate to true.
        // ...
    }
}

Why is it reported? #

A loose comparison using == is always true based on the types of the compared values. This means the condition is redundant – it will never evaluate to false. This usually indicates a logic error, a misunderstanding of PHP’s type juggling rules, or code that has become dead after refactoring.

PHP’s loose comparison (==) performs type coercion before comparing, which can lead to surprising results. For example, 0 == '0' is always true because PHP converts the string to an integer for comparison.

How to fix it #

If the comparison is intentional, use strict comparison (===) which does not perform type coercion:

 <?php declare(strict_types = 1);
 
 function doFoo(): void
 {
-    if (0 == '0') {
+    if (0 === 0) {
         // ...
     }
 }

If the condition is always true, the conditional branch is unnecessary and can be simplified:

 <?php declare(strict_types = 1);
 
 function doFoo(): void
 {
-    if (0 == '0') {
-        // ...
-    }
+    // ...
 }

How to ignore this error #

You can use the identifier equal.alwaysTrue to ignore this error using a comment:

// @phpstan-ignore equal.alwaysTrue
codeThatProducesTheError();

You can also use only the identifier key to ignore all errors of the same type in your configuration file in the ignoreErrors parameter:

parameters:
	ignoreErrors:
		-
			identifier: equal.alwaysTrue

Rules that report this error #

PHPStan\Rules\Comparison\ConstantLooseComparisonRule [1]

Edit this page on GitHub

Theme