Description:
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Reflection classes can be extended but the parent classes doesn't make the usage of other extended classes.

As an example we extend the ReflectionClass and the ReflectionMethod class.

CustomReflectionClass extends ReflectionClass {

}

CustomReflectionMethod extends ReflectionMethod {

}

When using the CustomReflectionClass::getMethods method it returns an array of ReflectionMethod objects. It should be a possibility to register the CustomReflectionMethod class so that these will be returned by the CustomReflectionClass::getMethods method.

For the DOM extensions it exists the DOMDocument::registerNodeClass method for this scenario.