Error Identifier: notIdentical.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(int $i, string $s): void
{
	if ($i !== $s) { // error: Strict comparison using !== between int and string will always evaluate to true.
		// ...
	}
}

Why is it reported? #

The strict not-identical operator (!==) compares both value and type. When the two operands can never be of the same type, the comparison will always evaluate to true, making the condition meaningless. This usually indicates a logic error – the code is checking something that can never be false.

This error can be turned off for the last condition in an if/elseif chain via the reportAlwaysTrueInLastCondition option.

How to fix it #

Compare values of compatible types, or remove the unnecessary condition.

-function doFoo(int $i, string $s): void
+function doFoo(int $i, int $j): void
 {
-	if ($i !== $s) {
+	if ($i !== $j) {
 		// ...
 	}
 }

If comparing different representations of the same logical value, convert one operand first.

 function doFoo(int $i, string $s): void
 {
-	if ($i !== $s) {
+	if ($i !== (int) $s) {
 		// ...
 	}
 }

How to ignore this error #

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

// @phpstan-ignore notIdentical.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: notIdentical.alwaysTrue

Rules that report this error #

PHPStan\Rules\Comparison\StrictComparisonOfDifferentTypesRule [1]

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