second order macros FTR

opaque_types.php

--TEST--
Opaque types with macros that generate other macros :>
--FILE--
<?php

macro {
    type T_STRING·newtype = T_STRING·basetype;
} >> {
    macro { T_STRING·newtype } >> { T_STRING·basetype }
}

type Username = string;
type Password = string;

function register_user(Username $nickname, Password $password) : User {
    //...
}

?>
--EXPECTF--
<?php

function register_user(string $nickname, string $password) : User {
    //...
}

?>