Error Identifier: constructor.unusedParameter
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);
class Foo
{
public function __construct(int $value, string $unused)
{
echo $value;
}
}
Why is it reported? #
The constructor has a parameter that is never used within the constructor body. In the example above, the parameter $unused is declared but never referenced.
This only applies to non-promoted parameters. Constructor-promoted parameters (those with visibility keywords like public, protected, or private) are excluded because they serve the purpose of initializing properties.
How to fix it #
Remove the unused parameter if it is not needed:
<?php declare(strict_types = 1);
class Foo
{
- public function __construct(int $value, string $unused)
+ public function __construct(int $value)
{
echo $value;
}
}
Or use the parameter in the constructor body. Alternatively, promote it to a property:
<?php declare(strict_types = 1);
class Foo
{
- public function __construct(int $value, string $unused)
+ public function __construct(int $value, private string $unused)
{
echo $value;
}
}
How to ignore this error #
You can use the identifier constructor.unusedParameter to ignore this error using a comment:
// @phpstan-ignore constructor.unusedParameter
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: constructor.unusedParameter