Error Identifier: parameter.byRef
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 Base
{
public function doFoo(int $i, int &$j): void
{
}
}
class Child extends Base
{
public function doFoo(int &$i, int $j): void // error: Parameter #1 $i of method Child::doFoo() is passed
{ // by reference but parameter #1 $i of method
} // Base::doFoo() is not passed by reference.
}
Why is it reported? #
When a child class overrides a method from a parent class or implements an interface method, the pass-by-reference semantics of each parameter must match. If the parent declares a parameter as pass-by-value but the child declares it as pass-by-reference (or vice versa), the method signature is incompatible. This violates the Liskov substitution principle and will cause a fatal error at runtime.
How to fix it #
Make the parameter’s pass-by-reference declaration match the parent method.
class Child extends Base
{
- public function doFoo(int &$i, int $j): void
+ public function doFoo(int $i, int &$j): void
{
}
}
How to ignore this error #
You can use the identifier parameter.byRef to ignore this error using a comment:
// @phpstan-ignore parameter.byRef
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: parameter.byRef