Error Identifier: phpstanApi.varTagAssumption
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);
use PHPStan\Type\Type;
use PHPStan\Type\StringType;
function doFoo(Type $type): void
{
/** @var StringType $type */
$type->describe(\PHPStan\Type\VerbosityLevel::value());
}
Why is it reported? #
A @var PHPDoc tag is used to narrow the type of an expression to a specific PHPStan type class. While the PHPStan class referenced in the @var tag may be covered by the backward compatibility promise, assuming that a value currently represented by one type class will always be that specific class is error-prone and dangerous.
PHPStan’s internal type representation can change between versions. A value that is currently a StringType instance might be represented differently in a future version, even if the StringType class itself still exists.
How to fix it #
Instead of using @var to assume a specific PHPStan type class, use the type’s API methods to query its properties:
<?php declare(strict_types = 1);
use PHPStan\Type\Type;
-use PHPStan\Type\StringType;
function doFoo(Type $type): void
{
- /** @var StringType $type */
- $type->describe(\PHPStan\Type\VerbosityLevel::value());
+ if ($type->isString()->yes()) {
+ $type->describe(\PHPStan\Type\VerbosityLevel::value());
+ }
}
See also: Backward Compatibility Promise
How to ignore this error #
You can use the identifier phpstanApi.varTagAssumption to ignore this error using a comment:
// @phpstan-ignore phpstanApi.varTagAssumption
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: phpstanApi.varTagAssumption