Nested Attributes
Arguments of attributes may be literals, such as integer or strings: they can also be other objects.
This feature was introduced in version 8.1. The objects must be created with a new expression, with their respective argument position or name. The created object is not necessarily an attribute itself, and they may also be created with another new expression.
<?php
#[
MyAttribute(
new OptionA('a'),
new OptionB(new OptionC(), 3)
)
]
function headers() : never {
}
?>