The expression return array($this->instances, $this->proxies) returns the type array<integer,array> which is incompatible with the return type mandated by Yiisoft\Yii\Gii\GiiInterface::getGenerators() of Yiisoft\Yii\Gii\GeneratorInterface[].
In the issue above, the returned value is violating the contract defined by the
mentioned interface.
Let's take a look at an example:
interfaceHasName{/** @return string */publicfunctiongetName();}className{public$name;}classUserimplementsHasName{/** @return string|Name */publicfunctiongetName(){returnnewName('foo');// This is a violation of the ``HasName`` interface// which only allows a string value to be returned.}}
In the issue above, the returned value is violating the contract defined by the mentioned interface.
Let's take a look at an example: