phpstan.unknownExpectation

Code example

<?php declare(strict_types = 1);

use function PHPStan\Testing\assertType;

$type = rand(0, 1) ? 'int' : 'string';
assertType($type, $value);

Why is it reported?

PHPStan's test assertion functions (assertType, assertNativeType, assertSuperType, assertVariableCertainty) require the expected type to be a literal string so that the expectation is unambiguous. When the first argument is not a constant literal string, PHPStan cannot determine what type was expected.

This also applies to assertVariableCertainty, where the first argument must be a static call to TrinaryLogic::createYes(), TrinaryLogic::createMaybe(), or TrinaryLogic::createNo().

How to fix it

Pass a literal string as the first argument:

 use function PHPStan\Testing\assertType;

-$type = rand(0, 1) ? 'int' : 'string';
-assertType($type, $value);
+assertType('int', $value);

For assertVariableCertainty, use a direct TrinaryLogic static call:

 use function PHPStan\Testing\assertVariableCertainty;
 use PHPStan\TrinaryLogic;

-assertVariableCertainty($certainty, $variable);
+assertVariableCertainty(TrinaryLogic::createYes(), $variable);